Pegasus

Volume XXVII Number 2

March/April 2001

Letter from the Editor

Greetings from your new editor. I’m proud to say that (by the skin of our teeth) there will be no interruption in the publication of Pegasus. I won’t, how-ever, lie to you good people and say that it was an easy transition. (I should have known, judging by the looks on peoples’ faces when I volunteered.) I owe very much to the generosity of the previous editor, Bob Capone, for the software dona-tion, and to Dave Brown, for delivering said software to me.

Next on my thank-you list is our President, Barry Shupp, for taking time to help test software, brainstorm, and especially for that drawing of a pegasus (I still say it looked like a cat, but who am I to judge?)

Please direct feedback regarding layout and content to my e-mail address listed to the right, or just corner me at the next meeting and let me know what you think we should put in next time. With the support of club members, we can keep Pegasus flying high.

President's Message

Well, club members, the worst of Winter is behind us, and we can eagerly look for-ward to warmer temperatures, and still hopefully retain some of the crystal clear skies Winter brings. We have many good programs coming up , as well as our annual Starwatches for various groups. The first event is at Nolde Forest Environmental Center on Friday night March 2, at 7:30 PM. Help if you can. On March 8, come to the monthly meeting and hear a very interesting program about the newest and latest innovations in lightweight astronomical mirrors. See and touch actual samples (but don’t drop them!). Dr. Peter Chen of Goddard Spaceflight Center is our guest tonight. Let’s make him feel welcome with a big turnout! The BIG event this month is for ourselves- the Messier Marathon on March 24-25 to be held at the Flying Field (see web site for directions). It should be an interesting experience as we battle the elements and each other to SURVIVE- oops that’s another show. Bring yourselves, bring your friends (bring some food!) to share as we attempt to survive the night. Oh, and try not to make too much noise-- I want to get some shuteye.

Pres. Barry L. Shupp

Pegasus is a bimonthly publication of the Berks County Amateur Astronomical Society

Editor/Desktop publisher: Melody Gardner

E-Mail submissions may be made to: dblhlx@rcn.com

In this issue:

Treasurer’s Report

I thought you might like to have a report on our income and expense for the year 2000. Enclosed in this newsletter is a breakdown of how we made our money last year and how we spent it. We spent a lot of money, but fortunately we had more money coming in. So we came out on top.

Linda Sensenig, Treasurer

Treasurer’s Letter

BCAAS FINANCIAL STATEMENT FOR 2000

Many of you have re-newed your magazine subscription through the BCAAS. In the event you gave me money to renew and you still receive an overdue reminder a month or so later, please do not disregard the notice. Contact me. Usually it is just a case of my check crossing in the mail with their overdue reminder and everything is okay. However things can go wrong. Checks can get lost in the mail. The publisher might have misplaced the check. Okay - I might also have forgotten to send the check. So, if you receive an overdue reminder, let me know. I’d rather call the publisher and find out everything is okay than not call and find out there was a problem.

Linda Sensenig, Treasurer

So Long , Old Friend!

Sometime between March 12 th – 18 th , a spectacular event will occur. Space Station MIR will be brought down, crashing through the atmosphere in a fiery decent. So will end the life of the world’s longest-lived space habitat. And it wasn’t ours. It was Russian.

The MIR was launched on February 20, 1986 less than a month after the U.S. Challenger disaster. Were the Soviets trying to upstage us, or was this simply the timing of things? Perhaps they felt a need to show the world that, yes, despite tragedy man still could successfully venture into near space. The first module was up, and over the next 15 years MIR would expand to over 138 tons, 33 meters in length, and about the same wide with a myriad of appendages providing living, and work spaces for over 100 visitors and crew. The craft has orbited this globe over 83,000 times, and performed many thousands of experiments. It was originally designed for a seven year hitch (sounds like a movie), but that was extended partly to provide a home base for the new space station, the ISS, as it was being built. I was always a bit envious that the Russians were up there like that and not US. The MIR evolved out of the Soviet Salyut program which were single module stations.

In recent years a fire, computer problems, and a nasty crash from a supply ship being operated like a giant sized video game by a cosmonaut knocked some of the luster off the aging space abode. Along with the changes in the Soviet government, and the advent of the ISS, money to operate the MIR became harder to find and justify and the last manned mission was actually funded by private concerns (Mircorp). So after a false alarm last year, the decision was made to b ring it down in a controlled reentry into the Pacific Ocean. Longitude 140 deg. W, latitude 47 deg. S if you’re interested. There are some planning excursions to the site. Recently a Progress M -43 craft refueled the MIR, and then was sent on a test plunge through the atmosphere in preparation for the main event. Another craft is now linked to the MIR to guide it on it’s final journey.

Satellites may be seen almost any night passing overhead if you know where to look for them or randomly with a little luck. I was attending the Mason-Dixon Star Party a few years ago while there was an ongoing shuttle mission. We all wondered if we could see the shuttle? Suddenly we spied a very bright "satellite" which we all assumed was the Shuttle passing between the stars. Satisfied with our bagged game, we continued with our observing. After a while there was some commotion among the group, as word spread that what we had seen was not the Shuttle, but the MIR! " Are you sure?" we asked collectively. "Yes" word came down, the boys from Goddard had figured the time of pass over before they got there and the bright object appeared just where and when they calculated. It DEFINETELY was the MIR! This was the first of probably two sightings that I’ve ever had of the MIR, and it was both exciting and wonderful. So it is with a heavy heart that I say to this spectacular craft with all its flaws--- So long, old friend! – you will be missed.

– by Barry L. Shupp

Mythology of the Night Sky—Hydra

We have all had those bad days at the work place. So, pity poor Hercules who went to work one day and was told he had to slay a nine-headed water snake called Hydra! Okay, so Hercules is a hero and slaying nine-headed snakes should be a normal day at the office. But THIS particular snake had the nasty habit of growing TWO heads whenever ONE was chopped off! Thank goodness Hydra isn’t anywhere near Hercules in the night sky.

Hydra is one of those very elongated constellations that wind its way amongst the constellations like a snake. It covers 95 degrees of sky from Cancer to Scorpio and contains no really prominent stars. The constellation cannot be seen in its entirety until the constellation Crater is on the meridian. Crater is even harder to find than Hydra! It is a constellation that goes back even farther than the Greek legend of Hercules.

Hydra is supposed to be the snake shown on a stone from the Euphrates dated 1200 B.C. and it is identified with the source of the fountain of the great deep. The Egyptians considered it the sky representation of the Nile. For an unspecified period, it’s winding course symbolized that of the moon, hence the moon’s nodes are called the Dragon’s Head and Tail. When a comet was in them, poison was thought to be scattered by it over the world! But we know better now - now this scenario of doom is attributed to Draco, instead.

"The Egyptians considered [Hydra] to be the sky representation of the Nile."

Linda Sensenig

 

Trip to Hayden Planetarium

by Melody Gardner

At about 7:45am on Saturday, January 27 th , 45 people gathered at the Schuylkill Valley High School, all in the name of Astronomy. As a group, we ranged from groggy 15 year-olds still wearing pyjamas (hey, it was a Saturday morning) to the old pros who had been up since 4:30am that morning. A brief delay in the arrival of our transportation (caused by the unfortunate passing of our bus driver) allowed us to wake up, eat, and watch some Saturday morning cartoons.

Once our bus arrived, we were quickly en route to our intended destination - the Hayden Planetarium, located inside the American Museum of Natural History in New York City. On the way, we were entertained by the on-board TV/VCR combo. The movie of choice? Nutty Professor 2: The Klumps.

At the museum, we were encouraged to explore any exhibits that piqued our interest, and reminded several times to "be at the Hayden Planetarium by 12:45 for the 1 o’clock show." The museum had four floors and more displays than we could see in a whole day, so everyone dashed to their favorites and tried to take it all in. The choices of my traveling party were close-up photos of details on the moon, a spiral walkway called the Cosmic Pathway depicting the evolution of the universe since the Big Bang, and the immense Willamette Meteorite. The Willamette Meteorite is awesome, both for the fact that it weighs almost 16 tons, and that it is a sacred object.

Its history begins in Oregon, where it was used for hundreds of years by the Clackamas Indian Tribe as a religious artifact. The tribe’s elders named the meteorite "Tomanowas," meaning Sky Person. Rainwater was gathered in its basins and used to anoint people and weapons, and represented all three elements in native religion – air, earth, and water. It was thought to bring strength to the tribe’s warriors, health to the ailing, and to aid in spiritual quests.

In 1902, a miner named Ellis G. Hughes "discovered" it, dragged it to his property, and let people see it for 25 cents apiece. By this time, the Clackamas tribe had been "relocated" to a mass reservation in California, and could not protest. At that time, the land was owned by t he Oregon Iron and Steel Company, who sued Hughes for the meteorite and won. In 1905, after displaying it in the Lewis and Clark Exposition in Portland, the meteorite was sold to an anonymous New York City woman for $20,600. Shortly thereafter, she donated it to the museum where it now resides.

In recent years, the Clackamas tribe has lobbied for the return of Tomanowas, citing it to be historically and spiritually significant to their tribe, and to the state of Oregon. What could have been an ugly court battle was resolved in June of 2000, when the museum and the Grande Ronde Tribal Council reached an agreement. The meteorite is to stay in the Rose Center of the museum without fear of lawsuits on the part of the tribe, on two conditions. First, the tribe must be allowed to perform its annual ritual uninterrupted. Second, the meteorite must stay on constant display, or the tribe will take it back.

As I was marveling at its sheer size, I noticed a tiny pool of water inside one of the more hidden pockets of the meteorite. I could not help wondering when the tribe had been there last, and anointed myself for good luck. We’ll see how it works, I suppose.

We made our way to the Hayden Planetarium for the 1 o’clock show, and were surprised by the number of people in line. There were over a hundred, obviously not all from our group. I guess it pays to have a big name in your planetarium show. The program, narrated by Tom Hanks, was a fresh perspective on our place in the universe. Starting with our own night sky, we moved outwards to our solar system, the Milky Way galaxy, the Virgo Supercluster, and then waaaaaaay out to the Observable Universe, with a friendly reminder that there may be even more out there that we can’t observe yet. The program stressed the fact that we’re just starting to see a tiny portion of what’s out there, and that it’s our responsibility to keep looking.

Following the show, we were on our own for another hour, and headed for some more exhibits in the main museum. First stop, Mexico and Central America, which had some very intricate jewelry and detailed stone carvings. Looking at small-scale replicas of Mayan temples reminded me very much of the Egyptian pyramids. Running short on time, we made a mad dash to the other side of the museum to view the Hall of Meteorites, Hall of Minerals, and (my favorite) the Hall of Gems.

Meeting the bus at 2:30pm, we were dropped downtown for an afternoon of sightseeing. Rockefeller Center was just a few blocks away, so we decided to watch the ice skaters for a while, and our timing was perfect. Just as we got to the railing overlooking the rink, a man pulled his girlfriend to the middle of the rink, got down on one knee and proposed! The entire place erupted in cheers as she said yes and put the ring on her finger. (Man, was it a rock; I could see it all the way from the balcony!)

After a little lunch, we headed to 34 th Street and the Empire State Building via subway MetroCards. The visibility on the observation deck (86 th floor) was only up to 5 miles, but we got a good view of the city from above. As dusk fell, the buildings started to glow, and the wind picked up dramatically.

Heading back uptown, we noticed a sign saying a movie was being filmed in the area, and were later found told that Robin Williams was in town. How cool! Searching Times Square for a place to have dinner, we settled on Planet Hollywood on 45 th and Times.

Next, it was time to hustle back to the bus for our 8pm departure. Most people fell asleep after all the activity, and those who stayed awake watched Wild, Wild West or talked about the events of the day. Ryan Hannahoe asked me if I thought an annual trip would be a good idea, and I had to say yes. It’s educational, fun for all ages, and I encourage everyone to give it a try.

A Layman's Guide to Stellar Evolution

This article is part of a series dealing with stellar evolution. The articles are written by a layman to convey that understanding to others. To that extent, errors and omissions should be excused. The series will cover the formation of stars, their energy production, assemblages, and their deaths. For comments, please contact the author.

Article 10, The Evolution of Stars in Multiple Star Systems

Somewhere between 50 and 80% of all observed stars are members of multiple star systems. These are systems in which one star actually orbits around one or more stars. Our sun is thus a bit unique, because it is not a member of a multiple star system, or even a binary system. Jupiter would have had to grow to 80X it’s mass before it would have become massive enough to ignite a fusion reaction in it’s core and thus become the second star in our stellar system.

The presence of one star in orbit around a second star can greatly perturb the evolution of the first star. The possible configurations of multiple star systems are many, due principally to the variety of individual types of stars and the possible different combinations that can be envisioned by their evolutionary stages. A few specific cases of multiple star systems are particularly noteworthy of discussion.

Scenario 1, Red Giant and a White Dwarf in co-orbit.

As the Red Giant’s outer layers swell in response to the onset of new sources of energy, e.g. Helium fusion, in it’s core, the outer layers of the star expand way beyond the gravity field of the Red Giant and actually into the realm of the gravity field of the White Dwarf. In this case, some of the mass of the Red Giant star actually transfers onto the surface of White Dwarf. As this mass impacts the surface, a characteristic spectrum of energy is emitted due to the fusion process which ignites in a shell around the White Dwarf star. Such stars (actually star systems) are called supersoft x-ray sources and these systems frequently exhibit outbursts of x-rays. But with each outburst, more mass is transferred to the surface of the White Dwarf and ultimately it’s mass will exceeds the 1.4 solar mass limit that a White Dwarf star can support, and it becomes violently unstable and ultimately collapses into a neutron star. The resultant explosion is also called a supernova, but is a special case of a supernova, called a Type Ia Supernova. Because of the unique origin of this event, the maximum brightness of Type Ia supernova is typically very consistent from one star to the next or at the least their maximum brightness is quite predictable based on their rate of decay. Type Ia supernova differ from the supernova resultant from the explosive destruction of aging massive Red Giant and Supergiant stars. Supernova in these single star systems are classified as Type Ib, Ic, and Type II supernovae.

The predictable absolute magnitudes of Type Ia supernova based on the decay curve when compared to their observed brightness enables them to be used to measure distances, vast intergalactic distances. Because they are so bright, they can be seen across vast intergalactic distances and in fact they are used to measure the distance to other galaxies.

Scenario 2, Red Giant and a Neutron Star or Black Hole in co-orbit.

In this case, the Red Giant star spills mass onto the surface of the Neutron star or Black Hole. The impacting mass produces a predictable and characteristic X-ray emission spectrum. Many examples of binary stellar systems exist where the companion is unseen except for it x-ray spectrum. These stellar system are called x-ray binaries.

Scenario 3, Two Neutron Stars or Black Holes in co-orbit.

Co-orbiting Neutron Stars or Black Holes are thought to possibly coalesce into a single object with the extremely violent release of energy. These events may be the source of another type of event called a Gamma Ray Bursts (GRB.) The evolution of these objects and the resultant observable events are not very well understood on theoretical basis and are the topic of much current research.

Scenario 4. Merger of stars in high stellar density environments.

In the cores of Globular clusters, frequently stellar densities are hundreds of times higher than observed in our stellar environment. And observed in globular clusters are a type of star called Blue stragglers. These are massive, not stars, which should have long since evolved beyond their observed Main Sequence stage. Apparently two smaller less massive and longer lived stars have merged into a larger star which will now since the merger evolve at the more rapid rate of the massive star.

This article is the concluding topic in the series describing stellar evolution. I hope the series has been of interest and understandable.

Submitted by Ron Kunkle

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