Tucson Star Party

Solar & Star Party-TAAA, in conjunction with Astronomy Magazine at Pima Community College (PCC) EAST Campus
SOUTHEAST TUCSON
Solar Observing:  10 am to Sunset (6 pm)
Evening Star Observing: 6 – 9 pm
Viewing Location:  PCC Astronomy Domes on south side of campus

TAAA will have several solar telescopes during the day to safely view the Sun to include sun spots, solar prominence, and other solar activity.  During the evening we will have telescopes to observe some amazing solar system and deep-sky objects, to include:  the Planets Venus, Mars, & Uranus; Orion’s Nebula (a star nursery) & other gas clouds; Andromeda Galaxy (2.5 million light years away); double star systems; star clusters; and other celestial highlights.  Observing will take place near the PCC Observatories on the south side of the campus.  The PCC observatories will also be open for viewing.  This is a free event open to the public.

UPDATE (February 15, 2017).  Weather may be an issue.  If overcast or raining, we will likely cancel event.  Follow Tucson Amateur Astronomy Association events on Facebook for real-time update.

A Cosmos Carol

 

An AFSIG Article by Paul Trittenbach

This time of year always seems to carry with it a certain atmosphere. The holidays bring a dramatic change in people — both good and bad — along with the change in the weather. As a child, I remember this time of the year for all the holiday festivities and the specials that ran on television. One of my first experiences with a holiday story was the black and white movie version of Charles Dickens’, A Christmas Carol, starring Alastair Sim. This reverse version of Dr. Jekyll and Mr. Hyde, where Mr. Hyde turns back into Dr. Jekyll, was a stirring demonstration of two of the greatest human emotions: love and compassion! In the story a bitter old miser named Ebenezer Scrooge is transformed into a kindly and gentle soul after the visitation of the ghost of his former business partner, Jacob Marley, and three spirits who represent the ghosts of Christmas past, present and future.

As I sit here writing and listening to the music of Bob Marley (I don’t have any works by Jacob) I am reminded that I have to complete an article for December. Bob Marley may not be appropriate Christmas music but he does remind me of Jacob and that moving story by Charles Dickens. So here I am to haunt you with the forecast that this Christmas you will be visited by three spirits: the ghost of Stellar Past, Stellar Present and Stellar Future—all in one night. In their presence and enlightened by the knowledge of their workings I hope that you will be transformed into a new man. May the spirits move you and forever transform the way you see the universe.

Now that you have made it through the Thanksgiving holiday and are hoping that Santa is going to bring you a workout video, let’s start with a workout warm-up by lifting and toting that telescope. 1 and 2 and lift and carry and set up the tripod; 3 and 4; and collimate and…
There’s really nothing like a good workout to get the heart pumping and keep the joints flexible. But we are also going to workout our eyes and brains as we ponder the celestial objects overhead.

Wintertime brings on a great deal more than an opportunity to test your mettle against the frigid cold of the season. Darkness falls early this time of the year, so it’s easy to get outside and see many of the spectacular objects of December. In a single night, my neighborhood becomes haunted by the ghosts of stellar past, stellar present and stellar future. I’m no Scrooge! Every December, around Christmas, I pull my telescope out of the closet and set it up in front of my house to present the entire neighborhood with a Cosmos Carol. What could be a better and bigger gift than offering everyone the entire universe?

But I have a real star Party! I purchase bulk cookies, hot chocolate and coffee and have a microwave handy to warm the milk for the chocolate and a coffee marker for fresh coffee.What could possibly complement a good workout better than hot chocolate and cookies? I have a portable radio handy and put on some music to create ambiance for the evening. You can start the evening with appropriate stargazing music, such as the Planets by Holst or you may choose to create a compilation of astronomy related music. For me, music and stargazing goes hand-in-hand.

Ebenezer’s transformation from Mr. Hyde into Dr. Jekyll centers on a couple of supporting characters that include his clerk, Bob Cratchit and his entire family, and Ebenezer’s nephew and his family. Scrooge is visited by the spirit of Marley who informs him that he will be visited by the ghost of Christmas past, present and future to be shown the error of his ways and given another chance to make things right. As a reformed man, he wakes up to a new day — Christmas Day — with a brand-new heart.

Ebenezer had to wait until the clock struck 1 AM before he was able to start his journey to becoming a transformed man. You will be able to start your journey as soon as the sun goes down and your telescope is set up. Ebenezer’s journey to New Manville begins with a visit by the ghost of Christmas past, who shows him the pain and tragedy of all the things that Ebenezer missed — including lost love — during his youth. The universe is far kinder to us because light travels at a fixed rate of speed and we are able to journey into the past by simply pointing our telescopes anywhere. In essence, we haven’t missed anything from the stellar past. Nature offers up her secrets if we look far enough across the cosmic ocean. But the ghost of stellar past does reveal to us that there is pain and tragedy in the death throes of stars!

 

The Ghosts Of Stellar Past

Located 1500 light years from Earth in the sword of Orion’s belt is M42, the Great Orion Nebula. This combination reflection and emission nebula is the product of an enormous explosion of an old red giant millennia ago. When the fuel of that star was exhausted, its outer layers succumbed to gravity and collapsed into its core within a few seconds, until the atoms could no longer crowd together. With the explosive force of thousands of hydrogen bombs they were shot away at supersonic speeds into interstellar space.

The result is an expanding cloud of dust and gas that today occupies an area of 24 light years across by 50 light years high. As the cloud continued to expand outward at supersonic velocities the gases and dust crashed into one another further compressing them to form more complex molecules, including the organic molecules of living things. The death of the red giant mother that led to the creation of M42 also gave birth to new stars and nascent solar systems. Within M42 there are 700 known stars, 150 of which possess protoplanetary disks. These stars are at various ages of formation with the youngest and brightest members believed to be only 10,000 years old and the oldest no older than 300,000 years. Within dense cocoons of gas new protostars are

M42 (Messier 42), the Great Orion Nebula is a prolific star producing region with 700 known stars, 150 of which have protoplanetary disks. M43 is on the upper right. Hubble Image
M42 (Messier 42), the Great Orion Nebula is a prolific star producing region with 700 known stars, 150 of which have protoplanetary disks. M43 is on the upper right.
Hubble Image

forming.

At the center of the nebula is a collection of four stars that form a trapezoidal shape known as the Trapezium. These four stars emit light in the ultraviolet region, exciting the surrounding gas and causing them to glow in the brilliant colors we see in images of the nebula. At the same time, the energy of the stars is carving a cavity within the nebula and causing many of the young stars to erode away. The nebula is both mother and cannibal!

Dark, cavernous areas within the nebula contain BOK globules. This is protostellar matter that will collapse under the forces of gravity to ignite as stars. In addition to the young, hot stars, the Hubble space telescope has spotted numerous black dwarfs within the nebula. These objects are too small to become stars and remain cold because they cannot sustain their cores way stars like our sun do. The Great Orion Nebula emits light predominately in the ionized oxygen region. You will find that an OIII filter will help you to pull out details of this stellar ghost.

M43 is a smaller nebula associated with the Great Orion Nebula and part of the entire structure known as the Orion complex. In images and shorter focal length eyepieces of our telescopes M43 seems to be attached to the Great Orion Nebula. It is also located 1500 light years from Earth in her prolific stellar nursery. Recent Hubble Space Telescope images have shown a lobe attached to M43 that is pushing back against the erosion caused by the ultraviolet radiation of the stars of M42.

Like a ghostly eye 2200 light-years away in the constellation Cygnus NGC 6826, the Blinking Planetary Nebula stares back at you through the telescope. This is a remnant of the star similar to our sun that grew to the red giant phase and then shed off its outer layers leaving a star of carbon and oxygen — a white dwarf — as a corpse. The gas layers expand into interstellar space and form a large bubble that emits light because it is excited by the ultraviolet radiation of the white dwarf at its center. Planetary nebulae result when low mass stars like our sun swell into a red giant phase at the end of their life. Instead of erupting in violent explosions, they shed their outer layers to create ghostly and beautiful clouds. Unfortunately, the white dwarf star that is left behind generates enough energy to quickly erode the nebula, and these types of nebulae have short periods of only about 10,000 years, as opposed to the billions of years of their parent stars.

A ghostly eye NGC 6826, the blinking planetary nebula does not actually blink. It is an optical illusion created when the eye shifts from center to edge of object.
A ghostly eye NGC 6826, the blinking planetary nebula does not actually blink. It is an optical illusion created when the eye shifts from center to edge of object.

Located 6500 light years away in the constellation Taurus is M1, the Crab Nebula. Like the Great Orion nebula, M1 is a supernova remnant, that has expanded to currently occupy a radius of 10 light years and is still expanding at a velocity of 1500 kilometers per second. Through the telescope M1 appears as an oval shaped mass of filaments. These filaments are the remains of the layers of the parent star’s atmosphere.

The beating heart of the Crab Nebula is a pulsar — a neutron star rotating at approximately 30 times per second. The pulsar is approximately 30 km across and emits radiation in x-ray wavelengths. This ionizes and excites the cloud of gas which is predominantly hydrogen and helium. The nebula is visible to telescopes with apertures as small as 4 inches but it glows at a magnitude of 9.0 and details of it can only best be experienced through a large aperture telescope. The pulsar beating at its heart is only visible through apertures of 20 inches or larger.

The supernova explosion that created M1 was witnessed by Chinese astronomers in 1054 A.D. It glowed so bright that it could be seen in the daytime and people could read by it at night for two months after the initial explosion. According to Chinese records M1 was the brightest object in the sky, next to the moon, and reached the magnitude of -7.0. It remained visible in the night sky for 653 days after its initial discovery.

 

Powerful tendrils of gas are M1, excited by the pulsar at the nebulas' heart NASA Image
Powerful tendrils of gas of M1 are excited by the pulsar at the nebulas’ heart
NASA Image

The clock struck 2:00 and Ebenezer was awaken by the spirit of Christmas Present. Ebenezer was taken along the streets of the city and shown the tragedy of those who were less fortunate. He had walked among those streets every day and seen the suffering of the masses but he chose to remain blind to them and ignorant of the fact that if all men truly loved each other they could solve all human suffering. The second ghosts to visit us, the Ghosts of Stellar Present, will take us through the streets of our “star city,” the Milky Way, and show us some souls that burn brightly — in some cases upon other worlds. However, I caution you to not be complacent because even our star, the sun, could rear up an ugly head and deliver a storm that could one day leave us hoping for mercy. Humans may be cruel but nature has no concept of good and evil. Its cycle of destruction and creation are simply defined as “existence”.

 

Ghosts of Stellar Present

If you need to show a ghost of stellar present, you wouldn’t have to go any farther than your backyard. Our sun is an excellent example of a medium yellow star that burns brightly enough and long enough to sustain planets that harbor life. If you own a solar telescope or solar filter and you prefer to set up in the daytime, than the sun would be both an easy target and a well-known celestial object for presenting as a ghost of stellar present. But if you’re looking for a nighttime analog there are billions of type G stars in the Milky Way galaxy. First, we will start by talking about our sun. Regardless of any nighttime analog you may choose, the knowledge that you will glean about our sun will be applicable to understanding the stellar object.

Visible light image of sun, with Venus transiting. The sun is a type yellow type G star approximately 4.5 billions years old with a life cycle of 10 billion years. NASA Image
Visible light image of sun, with Venus transiting. The sun is a type yellow type G star approximately 4.5 billions years old with a life cycle of 10 billion years.
NASA Image

Located approximately 93 million miles away is our star, the sun. The sun is the beating heart of our solar system and is in essence a hot, glowing ball of plasma with an influence that extends well beyond the orbit of Pluto. Without our sun there would be no heat or life here on earth. The gravity of the sun holds the entire solar system together. The sun generates an electrically charged magnetic field that is conducted throughout the solar system creating a stream of electrically charged gas — the solar wind — which travels through the solar system in all directions.

The sun’s interaction with our planets drive the ocean currents, weather, climate, our seasons, the radiation belt and the auroras. Although it is the only one we have, our sun is one of billions of yellow stars throughout the Milky Way. The sun and our entire solar system formed within a giant rotating cloud of gas and dust — a solar nebula — approximately 4.5 billion years ago. As gravity caused the nebula to collapse, it began to spin faster creating a flattened disk. Our sun was created when the bulk of the material, 99.8% of the mass of the solar system, was drawn to the center, and under the influence of gravity ignited to create our star.

Our sun is 1.3 million times the size of the earth! With a radius of 695,508 km and as much as 332,946 times the mass of the earth, our sun may seem like a very large star, but it is in fact an average star and there are many more that are several times larger. Different parts of the sun rotate at different velocities but at the equator the sun spins around approximately once every 25 days. At its poles, the sun spins around once every 36 days.

This ultraviolet images shows some of the sun's power that is invisible under visual wavelengths. NASA Image
This ultraviolet images shows some of the sun’s power that is invisible under visual wavelengths.
NASA Image

The sun’s mass, like all other celestial objects, is held together by gravity. The sun itself consists of six different regions: the core, the radiative zone, the convective zone, the photosphere (which is the visible region), the chromosphere and the corona. The temperature of the sun’s core is 27,000,000°F, a temperature that is hot enough to sustain thermonuclear fusion. At the core, atoms of hydrogen are fused (cemented together) to create helium and more complex elements.

The core creates energy to produce all the heat and light of the sun. The energy is radiated outward from the core into the radiative zone where it bounces around for 170,000 years until it can reach the top of the convective zone. In the convective zone the temperature drops to 3,500,000°F and large bubbles of hot plasma begin to migrate outward. Although the temperature of the surface of the sun is only 10,000°F it is still hot enough to create and boil carbon!

The photosphere is a 300 mile thick region from which most of the sun’s radiation escapes into space. In our eyes this radiation appears as sunlight and takes eight minutes to reach the earth. Above the photosphere is the chromosphere and the Corona, a tenuous, thin atmosphere. When we hear of or see solar flares and sunspots for ourselves, this is the area in which they occur. The light of this region is far dimmer than that of the photosphere and the only time that we are able to ever see it is during a solar eclipse. Ironically, the temperature in the sun’s atmosphere increases as the altitude increases — reaching as high as 3,500,000°F. The source of this heating is a scientific mystery.

The sun is a giant dynamo that generates a complex magnetic field that extends outward into interplanetary space. This region of influence is known as the heliosphere. A stream of electrically charged gas flowing from the sun carries the magnetic field into interstellar space. As the sun rotates, its magnetic field is churned outward in a giant rotating spiral.

Solar eruptions are common demonstrations of the sun's power. The sun can emit harmful burst of radiation, coronal mass ejects and flares that can threaten modern existence. NASA Image
Solar eruptions are common demonstrations of the sun’s power. The sun can emit harmful burst of radiation, coronal mass ejects and flares that can threaten modern existence.
NASA Image

The sun is not always a quiescent star friendly to life on earth. It goes through periods known as solar cycles, which occur approximately every 11 years. At that time the geographic poles of the sun change their polarity and the photosphere, chromosphere and corona transform from quiet and calm into violent. The height of this activity is known as the solar maximum. It is a time of sunspots, flares, solar storms and coronal mass ejections. They are the results of irregularities in the sun’s magnetic field and can release enormous amounts of energy and particles into space, some of which reach Earth. This space weather can damage satellites and affect the power grid, threatening the whole of civilization.

Forty light years away in the constellation Auriga is the giant double binary type G star, Capella (Alpha Aurigae). The two brightest stars of the system are type G, similar to our sun but about 10 times its diameter. The stars are orbited by smaller red binary companions. The two main stars are separated by only about 60 million miles, two-thirds the Sun-Earth distance and orbit each other every 100 days. Both the A and B stars are about 80 times as bright as our sun. Because of this, the system would be too hot to harbor complex life like that of Earth. Nevertheless, Capella is a good nighttime analog to our sun and a good choice for your nighttime viewing.

Capella A and B are both yellow-orange giant stars in a post-main-sequence phase. Both are older and many times larger than our sun. In this stage they have exhausted most of the hydrogen fuel at their cores and have expanded to five times their original size. Over the next few million years both stars will become red giants — a fate that will be shared by our sun in 5 billion years — and expand to hundreds of times their original size.

Capella A is the larger of the two stars with a radius 12 times that of our sun. Capella B as a radius of about nine times that of our sun. Both stars have masses and surface temperatures similar to Sol. Both stars are aged at around 500 million years old. Visually, Capella appears as a single star. A telescope resolves it into a type G binary, but the additional red dwarf binary companions will not resolve in amateur equipment.

Over the past few years red dwarf stars have come into light as astronomers have become more interested in them as possible targets for Earth-like planets. Red dwarf stars are much smaller than our sun and burn much cooler. But they also burn much longer and this combination opens the possibility to earth-like worlds occupying the Goldilocks zone in a proximity much closer to the star. Red dwarf stars also exist in a greater population than any other star type in the Milky Way galaxy.

Science fiction fans will remember that 40 Eridani A is the star of the fictional planet Vulcan, home to the first officer of the starship Enterprise, Mr. Spock. Unfortunately, no planet is known to exist around this star. Current technology is not up to the task of finding one. It has been calculated that a planet circling 40 Eridani A would be located at position of .68 AU away, 2/3 the sun-earth distance. The B and C stars would burn brightly in the Vulcan sky. Although both stars would be visible during the daytime their light would not be bright enough to completely negate the nighttime sky from the inhabitants of 40 Eridani A.

40 Eridanis C is a red dwarf star located 16.5 light years away in the constellation Eridanus. It is a member of a triple star system of Omicron Eridani composed of dwarf stars. The A star is a main sequence dwarf type G, similar to our sun but much smaller. 40 Eridani B is a white dwarf and 40 Eridani C is a red dwarf. The white dwarf B star would put out so much radiation that any planets circling it would be sterilized by its ultraviolet radiation. 40 Eridanis C flares with periodic increases in x-rays in addition to visible light. This, too, would prohibit the possibility of life developing on any planets orbiting this world. However, the star is an example of an M class dwarf and should be considered a good analog to Proxima Centauri B, our nearest neighbor which is now believed to harbor an Earth-like world.

Because of its close proximity to earth, 40 Eridani C is an easy telescopic target and another example of a Ghost of Stellar Present. Recently the news was buzzing with the announcement of the discovery of a small, possible earth-like planet circling our nearest neighbor, Proxima Centauri B. It appears that this planet resides in the Goldilocks zone of that red dwarf. When scientists talk about Earth-like worlds they are speaking of stars are in the right place – the right distance from their sun — to harbor liquid water. This doesn’t mean that the planet may contain complex life like our own. The search for life in the universe, at the present time, is a search for whatever life we may find. Most of this will probably be microbial similar to the single celled organisms we see on earth. Most of them will probably be extremophiles and thermophiles, organisms capable of existing in environments that would be hostile to us.

The existence of life on other worlds will certainly be a transformative experience for the human race. Given the abundance of organic molecules in the interstellar medium it seems highly unlikely that life doesn’t occur in many places throughout the universe. Scientists are even turning to the moons of Jupiter and Saturn to find primordial life. Even extinct life, contained in fossils on Mars and possibly our moon, could teach us a great deal about the chemistry of life and may help to solve the debate over whether life originated here or was transported to earth via comets.

In A Christmas Carol, Ebenezer’s transformation is completed by a visitation from the ghost of Christmas future. After Ebenezer witnesses the loneliness and sadness that he could have prevented during his lifetime he repents as he kneels at his own grave. In the story, Christmas Day is tomorrow and we are led to believe a Christmas future, the day upon which Ebenezer is resting in a lonely grave, may be tomorrow. In fact, for all he knows Ebenezer may already be dead and the ghost of Christmas future may be simply showing him events that he cannot prevent. After all, he does ask a non-responsive ghost of Christmas future if the events he has witnessed are things that will be or things that must be.

As soon as Ebenezer awakens to realize that he is still alive and the ghosts have delivered upon their promise to reveal all to him in one night, he is an elated man (on Messier cloud nine) who immediately sets about to his business — mankind! Now I don’t know about you, but if I were kept up all night I would not be as cheerful as Ebenezer — at least not before I’ve had a few hours sleep and an IV bag full of coffee. That even includes awakening on Christmas Day with the knowledge that under the tree was that workout DVD I so coveted!

The Ghosts of Stellar Future

We do not have to fear the ghosts of stellar future because that takes place billions of years from now. Eventually our own star will bloat into a super red giant, then shed off its outer layers and become a planetary nebula similar to the Ring nebula in the constellation Lyra. The universe itself may have already seen its greatest star forming phase. As dark energy propels all the atoms of the universe apart into an eternally inflating universe, the stars we see today will eventually fade from view until they themselves are flung apart by the forces of that energy. While A Christmas Carol may have a happy ending, a Cosmic Carol will have a cold and tragic one.

The ghosts of stellar future that will visit upon us will be the ghosts of the astronomical near future — billions of years from now. We can see many of the spirits roaming our own Milky Way galaxy today, old stars that have grown into the monsters of the present. They are examples of stars of the future — stars like our sun and many of the others currently inhabiting our galaxy and the rest of the universe.

If there is an outstanding of the ghost of stellar future in December’s sky it would have to be Betelgeuse in the constellation Orion. Designated as Alpha Orionis, Betelgeuse is one of the brightest stars in the winter sky and part of the winter triangle. Betelgeuse is a super red giant near the end of its life cycle. If Betelgeuse was located at the center of our solar system its surface would extend beyond our asteroid belt, consuming all the inner planets out to Mars. It is located 640 light years away in the shoulder of the constellation Orion. When Betelgeuse dies it will produce an enormous supernova explosion, sometime within the next million years.

This is the first direct image of a star other than the Sun, made with the Hubble Space Telescope. Called Alpha Orionis, or Betelgeuse, it is a red supergiant star marking the shoulder of the winter constellation Orion the Hunter. The Hubble image reveals a huge ultraviolet atmosphere with a mysterious hot spot on the stellar behemoth's surface. The enormous bright spot, more than ten times the diameter of Earth, is at least 2, 000 Kelvin degrees hotter than the surface of the star.
This is the first direct image of a star other than the Sun, made with the Hubble Space Telescope. Called Alpha Orionis, or Betelgeuse, it is a red supergiant star marking the shoulder of the winter constellation Orion the Hunter. The Hubble image reveals a huge ultraviolet atmosphere with a mysterious hot spot on the stellar behemoth’s surface. The enormous bright spot, more than ten times the diameter of Earth, is at least 2, 000 Kelvin degrees hotter than the surface of the star.

Like the star Mira in the Constellation Cetus, Betelgeuse is a runaway star plowing through interstellar space at 30 kilometers per second and leaving a bow shock in its wake. It is also classified as a semi-irregular variable star with periods of variability from 400 to 2100 days. Betelgeuse possesses at least 20-30 times the mass of our sun and 2 million times its volume. It shines 100,000 as brightly as our sun. High mass stars such as Betelgeuse exhaust their fuel very quickly, existing for only a few million years, as opposed to our sun which will live for billions of years. Betelgeuse is aged at 10 million years and is already nearing the end of its lifespan!

Stars at least five times the mass of our sun can grow into super red giants at the end of their life cycle and go out in a grand supernova explosion that results in either a nebula, similar to the Great Orion nebula, a neutron star or a black hole. The fate of Betelgeuse is likely to be another nebula similar to that of the Great Orion Nebula (M 42).

Stars 1.5 to 3 times the mass of our sun grow into red supergiants, die in a supernova explosion and leave a neutron star, while other, more massive stars can go on to produce a nebula or black hole. All of that depends upon their mass and how their atoms recombine in the final moments of their lives. Stars 15 times the mass of the sun may continue to contract to form a singularity—a black hole.Because of its mass Betelgeuse likely to become a neutron star. Neutron stars occur when the core of the star is compressed tightly and the electrons are stripped off from the atoms. The result is a large ball of nuclear material — matter of the atomic nucleus — the size of a city, such as New York or Paris. Consider an object twice the size of our sun compressed down into a city-sized object. The core is so dense and the gravity is so enormous that a single teaspoon of neutron star would weigh billions of tons!

Because of its density the gravity of a neutron star is so immense that to escape it you have to have a velocity of half the speed of light. A mountain on the surface of a the star would only be millimeters high. Light traveling around such a star would be gravitationally lensed, so astronomers would be able to see things behind a neutron star. A neutron star would compact 500,000 times the mass of the earth into a sphere of only 12.4 miles.

An ultra luminous pulsar in the galaxy M82. It is one of two known pulsars of this type in that galaxy. NASA Image
An ultra luminous pulsar in the galaxy M82. It is one of two known pulsars of this type in that galaxy.
NASA Image

As the core of the star continues to collapse inward, its rotation increases in it can spin up to thousands of times per minute. These rapidly rotating stars are known as pulsars. They can emit beacons of light that can be picked up in the x-ray and radio spectrum. When viewed from Earth these pulsars resemble the beacon of a lighthouse. As material from the pulsar accelerates within its magnetosphere it produces gamma rays, which can slow the pulsar down. If the beam from a pulsar does not flash in the direction of earth, cannot be seen. All pulsars are neutron stars but not all neutron stars are pulsars.

Magnetars are neutron stars that have magnetic fields thousands of times stronger than the average neutron star. The drag of the magnetic field slows the star down so it takes much longer to rotate than a pulsar. Magnetic fields can be so strong that they will distort the shapes of atoms! A fracturing of the surface of a magnetar can release a large pulse of radiation that can be detected up to tens of thousands of light-years away. This release of radiation is known as a starquake. Magnetars can remain active for 10,000 years, after which the magnetic field is fully dissipated and the star cools down.

Sometimes neutron stars will collide and create a black hole. This process takes milliseconds to

occur. The rapidly rotating black hole created from the two neutron stars spins so fast that it emits jets of material that travel light years back into space. Images of these “quasars” have been seen at the centers of galaxies where supermassive black holes are rapidly spinning and digesting orbiting stars! In their gluttonous feeding, however, enormous amounts of material are ejected from the poles of the black hole into interstellar space. These are the jets that we see in images of quasars. Colliding neutron stars produce gravitational waves that can be detected with devices such as the LIGO detectors here in the United States.

What a piece of work is a man! How noble in reason, how infinite in faculty! In form and moving how express and admirable! In action how like an Angel! In apprehension how like a god!
Hamlet, Act 2, scene 2

Oh, if William Shakespeare had only been an astronomer! He might have written about what a piece of work the universe is. How elegant in its construction and workings, how infinite in breadth! How moving in mystery and intrigue! How secretive and yet willing to share her secrets! To look into her eyes is to look into a mirror and see yourself!

General Meeting – January 2017

6:30 PM:  State of the Club

Speaker: TAAA President Ben Bailey

7:30 PM:  “A Night Watchman’s Journey:  My Life As A Searcher of Comets”

Speaker:  David Levy

 

The Great Whale

Call me Ishmael (my name is actually Paul). Whenever a balmy November wind blows across my bow and chills me to the bone, when the brisk November air suggests that autumn is turning to winter, when the skies of night become calm and tranquil and abound with good astronomical seeing, and whenever I find my heart longing for a dark observing site, I account it is high time to set sail into the infinite seas of the cosmos.

Pseudo Melville, The Great Whale

Plowing through interstellar space at 291,000 miles per hour the binary orange giant Mira leaves a 13 light year tail in its wake. NASA Image
Plowing through interstellar space at 291,000 miles per hour the binary orange giant Mira leaves a 13 light year tail in its wake.
NASA Image

 

An AFSIG Article by: Paul Trittenbach

Moby Dick is probably the most infamous manuscript of Herman Melville. Scholars may disagree that it was his best work, but the novel does touch the soul of any reader. Moby Dick is fraught with emotional and philosophical undercurrents that leaves an indelible mark upon those who voyage through it pages. Melville inspired me when I found my thoughts turning to create a web article for November. Both Moby Dick and my composition have something in common—a great whale!

The Constellation Cetus, the whale, swims in the 13.8 billion light year ocean of our universe among other constellations associated with water: Eridanus, Aquarius and Pisces. In Greek mythology Cetus was known as “the sea monster” from the myth of the princess Andromeda. According to the myth, Andromeda’s boastful mother, Cassiopeia, angered Poseidon (the god of the sea) and the Nereids (nymphs of the sea), by claiming that she was more beautiful than they. Poseidon sent Cetus to punish King  Cepheus and his wife Cassiopeia for the boast, requiring that they sacrifice their daughter to the sea monster or have it ravage their land.

King Cepheus and his wife chained their daughter to a rock so the sea monster could devour her. But just as the sea monster was about the partake of this delicacy, our hero Perseus entered the picture and killed Cetus, rescuing Andromeda from her fate. Later the two were married.

Cetus sits high in the southern sky and is prime for hunting by mid month. It possesses two red giants, one a pulsating variable—which is also a binary system— an orange giant and one G-type star smaller than our sun. It has 14 stars with planets and covers 1231 square degrees of space.  There are three meteor showers associated with Cetus: the Omicron Cetids, October Cetids and Eta Cetids. The constellation is also home to nine galaxies available to amateur astronomers.

Unlike Capt. Ahab, I am unwilling to chase this whale around any maelstroms or round Perdition’s flames. I just sit patiently and wait until the earth transits around the sun and the overhead sky turns to the stars of autumn. Then Cetus presents itself overhead. There are plenty of other celestial objects to keep me occupied in the meantime. But when  Cetus appears overhead it offers cosmic gems worth harpooning. In pursuit of our  quarry, let’s first turn toward the stars of Cetus.

“…the great floodgates of the wonder-world swung open…” 

Herman Melville, Moby Dick, or The Whale

Regardless of what aperture you choose you will never see Alpha Ceti V, the planet to which the genetically superior Kahn and his band of rebels was exiled by Capt. Kirk in Star Trek, the Original Series, after attempting to commandeer his ship. Made famous by the episode “Space Seed” and revisited in the motion picture Star Trek II, “The Wrath of Kahn”, Alpha Ceti (Menkar) has been deceptively hiding her planets. Of all the extrasolar planets discovered thus far none have ever been found around this star.

Designated as the alpha star, Alpha Ceti is actually the second  brightest star in the constellation. Located 249 light years away, at magnitude 2.5 Menkar is a red giant with more than twice the mass and 89 times the radius of the sun. When it dies it will shed its outer layers and evolve into a planetary nebula, a fate that our sun will share in 5 billion years. Some people believe that Menkar is designated the Alpha Star because it sits close to the plane of the ecliptic and marks the path of the sun across the sky. In Arabic Menkar means nostril.  The star sits at the head of Cetus.

Deneb Kaitos—Beta Ceti— is the brightest star in Cetus. It is located 96.3 light years away and shines at a magnitude of 2.04.  Deneb Kaitos is an orange giant possessing 2.8 times the mass and 16.8 times radius of the sun. Deneb Kaitos has evolved from a main sequence star and is on its way toward becoming a red giant.

Plowing its way through interstellar space at 291,000 miles/sec the variable star Mira (Omicron Ceti) creates a bow shock and leaves a 13 light-year long tail of dust and gas in its wake. That light is visible only in the ultraviolet frequencies, and was detected only recently by NASA’s Galaxy Evolution Explorer telescope. Mira is a red giant star close to the end of its life. Mira has already ejected enough mass into surrounding space to  create 3,000 planets the size of our home.

When it dies it will shed off its outer layers and become a planetary nebula. Mira is also a binary system. The B star (Mira B) is a white dwarf that is accreting mass from the primary.  Images taken by the Chandra X-ray Observatory show that matter from the primary star is being consumed by the white dwarf. Both stars are separated by a  distance of 70 astronomical units.

The binary orange giant Mira and companion. Hubble image
The binary orange giant Mira and companion.
Hubble image

Mira is a pulsating variable star—the first of its kind to be observed—and is now part of a class of pulsating variables known as Mira variables (M Variables).  All of the stars in this class, 6 – 7000 of them, are red giants that pulsate with varying periods of brightness of between 80 to 1000 days. Mira has a period of 332 days and can vary in  brightness from magnitude 2.0-10.  Mira is located 420 light years from Earth.

Of all the likely candidates, you would think the Star Trek writers would have chosen for a place to maroon Kahn and his band of genetic supermen, you would think it would have been Tau Ceti. Tau Ceti is a yellow dwarf star 11.9 light years distant that shines at magnitude 3.5. Is one of a few G-type stars that possesses less mass and brightness than our sun.  In 1960 it was chosen by Frank Drake as one of the original Project SETI (Project Ozma ) candidates to search for intelligent life in the universe.

At millions of light years distant, galaxies are like great white whales swimming in our ocean universe.  In binocular’s and small telescopes they shine as nothing more than milky clouds on the dark backdrop of space. It is difficult for us to wrap our minds around the great distances of the cosmos. Even members of our celestial neighborhood are trillions of miles away — far beyond our reach by any means of the rules of the Einsteinian universe.

Compared to the distances in our cosmic neighborhood, these great white whales are  immense! But even the distances between them and the expanse of the universe itself makes them seem like amoebas in a drop of water! So here we are, Jonahs in the belly of a great white whale, staring out into the ocean with intense curiosity.

45 million light years away is Messier 77 (M 77, NGC 1068) a barred spiral galaxy at magnitude 9.6. It is one of the largest galaxies listed in the Messier catalog and the only Messier object in Cetus. It spans 170,000 light years in diameter and is the closest and brightest of the Seifert galaxies. These are galaxies that possess hot, highly ionized gases which emit intense radiation and glow very brightly. This radiation is caused by a very Active Galactic Nucleus (AGN) — a black hole — about 15 million times the mass of our sun! M77 also has very bright arms, the result of prolific star formation.

Spiral galaxies, M77 (face-on) and NGC 1055. Nasa image
Spiral galaxies, M77 (face-on) and NGC 1055. Note the red lanes in M77 and the large halo of NGC 1055. 
Nasa image

Located 250 million light years away is the spiral galaxy NGC 17. You will need a large aperture telescope to see this galaxy; it possesses a magnitude of 15.3. NGC 17 is believed to be a merger between two larger disk galaxies because it demonstrates prolific starburst activity and its core is still very rich in gases.

The barred spiral galaxy NGC 45 shines at approximately a magnitude of 10.4 and is  located 32.6 million light years away. You will want to use a large aperture telescope to   wrestle any details from this galaxy. Although it is very large, the surface details of NGC 45 are spread out and faint. This galaxy presents itself in a nearly face-on orientation to our plane of view.

At 236 million light years away the barred spiral galaxy NGC 47 shines at magnitude 13.5. Like NGC 17 and NGC 45 you will want to use a large aperture telescope to tease out any details from this galaxy. NGC 47 is a small galaxy with a very bright core.

Much closer to us, at 11.1 million light years is NGC 247, also known as Caldwell 62. NGC 247 is a small spiral galaxy— also classified as a dwarf spiral galaxy—  and one of the closest to the Milky Way. It is a member of the Sculptor group of galaxies. NGC 247 possesses a bright nucleus surrounded by stars, gas and dust. The gas forms bright knots in the HII regions that are scattered throughout the galaxy’s outer arm.

Images taken by the Hubble space telescope show that NGC 247 has a large void in the HII regions, which spans nearly 1/3 of the length of the galaxy. Stars in this void are old, red and faint, and indicate that star formation has been halted in this region. It is believed the star formation in this region has not taken place in at least 1 billion years!

At 60 million light years distance the face-on spiral galaxy NGC 1042 shines at magnitude  11.0. It is typically associated with a nearby galaxy NGC 1035 and believed to be gravitationally bound to it because both demonstrate a similar red shift. NGC 1042 possesses a very bright Active Galactic Nucleus (AGN).

Located 60 million light years away, NGC 1055 is the dominant member of a group of small galaxies which are part of the NGC 77 galaxy group. Viewed from our position, NGC 1055 is an edge-on galaxy approximately 100,000 light years across. This galaxy possesses a large box-shaped halo that extends far above and below the galactic plane. In appearance, it bears some resemblance to the Sombrero Galaxy, NGC 104.

NASA images show faint structures within the galactic halo that are believed to be   remnants of an interaction with a larger spiral that took place 10 billion years ago. Like NGC 77,  NGC 1055 is a prolific star producer.  NGC 1055 shines at magnitude 11.4 and will require a large aperture to be able to discern its structure.

NGC 1073 is a barred spiral galaxy similar to our own Milky Way that possesses a very active nucleus that glows in the HII region. It is 80,000 light years across and 55 million  light years away. Hubble space telescope images show visible dark dust lanes, glowing in the HII region, young clusters of blue stars and an active nucleus which likely contains a black hole. NGC 1073 shines at a magnitude of 11.5 so you will want a large aperture to view this galaxy.

NGC 1087 is 80 million light years distant and 86,800 light years in diameter. You will want a large aperture to capture this galaxy. It shines at magnitude 12.2. It is classified as an intermediate spiral galaxy, possessing a small central bar of irregular features  surrounding a disk. The overall surface brightness of the galaxy is very low.

Oh, Starbucks (Espresso, Frappuccino, iced coffee or dark roast)! Stand fast by my side. For I stand duty watch on the Forecastle and man the spyglass!

Pseudo Melville, The Great Whale

When the cold November wind blows across your bow and the nights become tranquil and accompanied by good astronomical seeing, I hope that your heart will yearn to shove off to a remote dark location and set sail into the infinite seas of the cosmos. There is a diamond mine out there, among the stars—filled with cosmic gems.

The Trick Is The Treat

An AFSIG Article by: Paul Trittenbach

Under the darkness of a new moon sky on October 31 ghosts and demons will arise from the netherworld and walk upon the earth. This is the day of Samhain (pronounced “Sah-win”), summer’s end, a 2000-year-old Pre-Christian Celtic celebration held around November 1 for the ending of summer and the time of harvest. Some historical legends purport that the Celts lit bon fires and donned costumes to ward off the dead. In the eighth century Pope Gregory III declared November 1 All Saints Day and incorporated some of the Celtic celebration into the Christian.

Perhaps when humans invented religion we had a need to explain the good and evil we saw in each other, so we balanced the equation by creating the good gods above and the evil ones below. It is a theme that has permeated our literature and movies and has been handed down since the first spoken languages have appeared in our species. And throughout our history almost every culture has celebrated the dead in one way or another. All Hallows Eve was the evening before All Saints Day and later evolved into the modern day celebration of Halloween.

Modern-day Halloween is a playful way of dealing with death. It is a time when little goblins of the neighborhood come out to invade the night seeking treats and promising nasty little tricks to those who fail to deliver. To me, this night when the moon is dark is a great opportunity to dispel some of those demons with science. I propose that you offer them a treat they seldom if ever have experienced: a star party. It is an opportunity for fun suffused with education.

We begin our tour of celestial eye candy by introducing the pralines of the northern hemisphere: the double cluster of the constellation Perseus. NGC 869 and 884 lie 7,500 light years away. Star clusters are groups of stars that are gravitationally bound to each other and moving independently of the rest of the galaxy. The Perseus Double Cluster are the only two known clusters in the Milky Way that are gravitationally bound to each other and moving as a single component at 39 km/s (24mi/s) in our direction.

Each cluster consists of 300 known members of young blue-white stars 12.8 million years old. At the time when the light left these clusters to appear in the eyepiece of your telescope the first established human civilization was firmly planted between the Tigris and Euphrates rivers in the ancient land of Mesopotamia — it is today called Iraq. These were the Samarians, from which we have derived our modern-day word of summer. To them, as to us, the double cluster appears as a large, somewhat milky patch in the sky overhead and can easily be seen from a dark location.

This pair of open clusters is a stunning example of the treats available to amateur astronomers. I tell guests at public star parties that when they see these sparkling diamonds against the velvet black of space they will ask themselves why they never got involved in this hobby sooner. There are numerous other open clusters that you can compare against the Perseus Double Cluster; M38, 39, 34, 11 and the most infamous: M45, the Pleiades.

In contrast to the aforementioned open clusters are the globular clusters, such as M13. If the double cluster is the pralines of celestial eye candy then globular clusters must be the gumdrops.Turning to the globular’s immediately after showing the open clusters yields a stunning, “wow” moment for the audience. In addition to the visual impact of viewing the two types of clusters, both possess opposite historical and compositional backgrounds.

Globular clusters reside at the opposite end of the age spectrum. They are fossils of the cosmos nearly as old as the universe itself. M13 is 11.65 billion years old! Unlike open clusters which formed inside our Milky Way, globular clusters are nomads roaming the universe and temporarily taking up residence inside the halo of our galaxy. They are densely packed associations of stars — the proverbial Guinness book example of “how many people can you fit into a phone booth”.

On the evening of October 31 M13 will be in the western part of the sky, just above the horizon. This is the most densely packed globular cluster available to most of the northern hemisphere (Tucson, Arizona lies close enough to the southern hemisphere to catch a view of the Omega Centauri cluster). M13 consists of 300,000 known stars compacted into a spherical volume of 145 ly! In addition to explaining what a light year is in terms of distance, M13 is an exercise in warping the mind around celestial mechanics.

You can compare the distance between Earth and its nearest stellar neighbor, Proxima Centauri at 4.2 light years, away to the same spherical area at the center of M13. In the 4.2 light year distance between us and our nearest our neighbor M13 would have 100 stars! In the same spherical distance of 4.2 light years the core of M13 would be the residence of 1000 stars! You can point out that the known members of a star cluster are those that we are able to visually count and that the Milky Way is dominated by binary stars in addition to other star systems that consist of three or more members circling either one another or a common invisible axis.

At the time when the Kerbarian cave Culture of Haifa, modern day Israel, was being established the light from M13 was departing to arrive in your eyepiece. While those people were fabricating stone tools light from 300,000 stars shone brightly into the universe. M13 is located 22,200 miles away in the constellation of Hercules. It is a popular summertime object among amateur astronomers. From a dark site it appears as a small fuzzy patch and is easily viewed through a pair of binoculars or a small telescope. Telescopes, however, will resolve the patch into stars.

M2 and M15 both provide good examples of globular star clusters. M2 is probably easier to present from an urban area because of its magnitude of 6.4. At one time star clusters were grouped with the species of nebulae — murky patches of light scattered among the stars. The word nebula is ancient Greek for “cloud” and before the invention of telescope star clusters, galaxies and true nebulas were all cloud-like structures in appearance. Even into the early 20th century the Andromeda galaxy was known as the Andromeda nebula.

Now that you’ve demonstrated the magic of star clusters try pulling a binary star out of your hat. The constellation Cygnus, the Swan, hangs west of Zenith in October. Beta Cygni, otherwise known as Albireo appears as a single star to the unaided eye. However, it presents one of the most stunning binaries in the Milky Way galaxy. Albireo is also a test in color perception. One star is a cool orange while the other one is a hot blue. To my eyes, the primary appears as a golden yellow and the secondary is a hot blue. Together the two stars present a striking color contrast.

Alberio is located 380 ly (Light years) from Earth. Harvard University was being established when the light left Albireo to arrive In your eyepiece. The first and second component orbit each other with a period of 75,000 years. Two thirds of the stars in the Milky Way are binaries but few of them can boast the visual impact of Albireo. In addition to showing Albireo you may want to show the most common Milky Way binary, Polaris.

If you’re in the mood for telling ghost stories then nothing can be more appropriate than showing them a nebula. The best of the summer nebulae, the Trifid, Lagoon and Eagle lay low on the horizon. Those who have a good view of the southern sky may still be able to catch a fleeting glimpse of them. But there are other ghosts in the sky that we can turn our telescopes to.

Aside from most of the planetary’s, reflection and emission nebulae appear as ghostly apparitions of black and white clouds hanging in space. M27, the Dumbbell nebula, is one exception. From our viewing angle the dumbbell not only appears dumbbell-shaped, because of the way that its lobes have expanded from the white dwarf driving it, but it also appears black-and-white to our eyes. Located 1200 away these expanding clouds of gas have been blown from a star similar to our sun 4000 years ago. At the time of this star’s death the Babylonians were developing mathematics.

The outburst of expanding gas lobes witnessed on M27 are one light year across and expanding outward at a velocity of 20 mi./s. The Dumbbell nebula was the first Planetary Nebula (PN) ever discovered. An Ultra High Contrast filter (UHC) will help you to pull out the details of the Dumbbell. An additional nebula to look for would be the North America nebula. For additional details on the North American nebula see my Cosmic Gems article from August.

For a nebula of a different color try M57, the Ring nebula. At the time when the light left this nebula 2300 years ago King Ptolemy II of Egypt was only a few years away from building the very first lighthouse at the mouth of the Nile. It would be 400 feet high and seen from 40 miles away. But the Ring nebula is a more substantial lighthouse, with the light being pumped out by a remnant of a star of similar mass to our sun, which upon exhausting its hydrogen fuel shed its outer layers in the last, great gasp of death. The remnant of the star is a white dwarf no larger than our earth.

Viewed from our position the outward expanding shell of gas and dust are excited by the ultraviolet radiation emitted by the white dwarf and radiating a rainbow of colors. Although M57 is also a planetary nebula it is a colorful contrast to that of M27. The nebula’s expanding shell of gas is 1.3 light years in diameter. Nebulae provide an opportunity to discuss how chemicals are formed within stars and the explosions that occur after their death. It is also an opportunity to explain how new stars are formed along with any planets or life that may occur on them.

You gotta have monsters! No Halloween story would be complete without them. So now we turn to the Alpha Star of the Constellation Taurus: Aldebaran. Aldebaran, the eye of the bull, is an orange giant star located 65 ly away. When the light left the star Ethel and Julius Rosenberg were being convicted of selling A-bomb secrets to the Soviet Union by the United States.

Aldebaran is a variable star but his variability is virtually unnoticeable to the human eye. It is also a binary star, possessing a secondary that is only three light seconds away (as opposed to our sun which is eight light minutes away).At 43 times the radius of our sun ( the radius of our sun is 432,000 miles) Aldebaran is a monster, although far from being the largest star known. The largest star on record is VY Canis Majoris, a red hyper giant and a eighth magnitude star 1420 times the radius of our sun!

Of course if you really want to talk about monsters point to the area of Cygnus X1. You will not be able to show them this black hole through your telescope but you can tell them that it was the first confirmed radio source verified as a black hole. Black holes like Cygnus X1 are the Frankenstein’s of nature. Cygnus X1 is considered to be a stellar mass black hole possessing 14.8 times the mass of our sun. It is located 6,070 ly from Earth.

Periodically stars many times the mass of our sun exhaust their fuel and the remaining material loses his outward push against the attraction of gravity. The mass of the star is so great that the gravitational attraction overwhelms all existing matter which collapses inward to an point known as a singularity — a word that means “mystery”. So powerful is the attraction of gravity that nothing can escape it, even light itself. As a result, black holes are mysterious in nature, having yielded up clues only from stars around them — some of them they are cannibalizing.

The nearby star orbiting Cygnus X1 is HDE226868 a ninth magnitude O-type supergiant star. You should be able to locate this star through your telescope. Here is an opportunity to explain the invisible electromagnetic spectrum and the x-ray radio source that makes detecting a black hole possible. It’s also a chance to discuss the radio spectrum and how humans use it in our modern world.

Physicists and mathematicians have determined that the space and time near black holes is radically changed from the Newtonian laws of the universe. As a result, black holes have become a favorite subject of science fiction — including Star Trek where the Enterprise frequently utilizes them to travel back in time. Studies indicate that black holes are quite abundant throughout the universe. In fact, it is an irony that black holes seem to be destructors of stars and also the creators of galaxies.

The last object that I want to cover in my Halloween star party is M31, the Andromeda galaxy (Andromeda nebula). The Andromeda galaxy is a large spiral galaxy, like our Milky Way, except possessing twice the mass. Andromeda has 1 trillion stars and is the largest galaxy in our local group, a group of 45 galaxies, which constitutes part of a super cluster of 2000 galaxies known as the Virgo Super Cluster. It is approximately 220,000 ly across (the Milky Way is 190 ly across) and 2.5 million ly from Earth. At the time when the light first left the Andromeda galaxy to appear in your eyepiece humans were fashioning their very first tools.

M31 is our nearest galactic neighbor. It is on a collision course with our galaxy, which will take place in 3.75 billion years. It is visible to the naked eye as a large fuzzy patch in the constellation of Andromeda. It is visible through pair binoculars and easily viewed through low power in a telescope. The nucleus of Andromeda is so bright that overwhelms the eye of the observer Tell your guests that to get a good view they should use adverted vision — turn their eyes slightly off center of the galaxy to see the details.

I think a themed star party like one for Halloween would be a great way to have fun while providing education and sharing a fascinating hobby. I can envision some of you dressed up as Darth Vader and turning the little goblins of your neighborhood toward dark side of day. A star party like this would be a great team builder for your organization — with opportunities for a variety of topics, from mythology to science, history and science fiction, art and culture. It’s an chance to demonstrate how we’ve come a long way from how the ancients thought about the universe to science casting light upon the truth.

Of course a Halloween star party is about serving celestial eye candy. But it would be a nasty trick to forget the confectionery treats. Halloween is a costume party, and not just one for the youngsters, with sugary rewards. Perhaps in 4 million years when Andromeda merges with our galaxy we will have a new name for candy bar. For now, we still have the old standbys that we grew up with: Three Musketeers, Snickers, Baby Ruth, Kit Kat… — to share with the younger generations. But for now and into the foreseeable future, remember, you can’t star gaze without the Milky Way!

General Meeting – December 2016

Introductory Presentation – 6:30 PM

Title:  What’s New At The Astronomical League?

Speaker: Ron Kramer  (The Astronomical League)

Main Presentation – 7:30 PM

Title:  How DESI At Kitt Peak Will Search For Dark Energy’s Secrets

Speakers: Dr. Arjun Dey and Rob Probst  (NOAO)