Webfooted Astronomer The Seattle Astronomical Society

September 2006

Special points of interest: • Light Pollution • Hubble Captures A Rare Eclipse On • Strange Space Pinwheels Spotted Uranus

September Meeting: Meeting Information

Wednesday, September 20 The Southern Sky from New Zealand 7:30 p.m.

Denis Jansky Physics-Astronomy Building Room A102 SAS University of Washington Denis will give a Seattle presentation about his Come early at 7 p.m. for coffee recent trip to New Zealand and snacks and to visit with where he had six nights of your fellow members! observing with a telescope he brought for the occasion. Denis will discuss the equipment he brought and where he observed. He also will describe an interesting place where there is a full-scale functioning replica of Stonehenge. He will also share his impressions of the southern sky.

If you have questions or suggestions for future In this issue: meetings, don't hesitate to contact me, Bruce Kelley - From the President’s Desk 3 Seattle Astronomical Society - Programs August Meeting Minutes 5 [email protected]

September/October Calendars 8

NASA Space Place: 10 Deadly Planets

Space Bits: Current News 12

Seattle Astronomical Society Address Web Page: PO Box 31746 http://seattleastro.org Seattle, WA 98103-1746 WebfootWeb: [email protected] SAS Info Line: 206-523-ASTR E-mail: [email protected]

Board & Committees Special Interest Groups President: Thomas Vaughan, Dark Sky Northwest: Bruce Weertman, 206-772-1282, [email protected] [email protected] Telescope Makers: Peter Hirtle, Board Chairperson: Stephen Van Rompaey, 206-363-0897, 425-564-8619, [email protected] [email protected] Astrophotography: Keith Allred, First VP–Programs: Bruce Kelley, 425-821-5820, 425-869-8347, [email protected] [email protected] Vive La Lune (Moon): Pat Lewis, Second VP–Education: Burley Packwood, 206-524-2006, [email protected] [email protected]

Third VP–Membership: Janice Edwards, Sidewalk Astronomers: Paul Ham, [email protected] 206-522-7410, [email protected] Fourth VP–Publicity: Greg Scheiderer, 206-938-5362, Webfooted Astronomer [email protected] Editor: Vanessa Long Treasurer: Scott Cameron, [email protected] 425-745-5057, Circulation Managers: Pat Lewis & Joanne Green, [email protected] 206-524-2006, Secretary: Chris Karcher, [email protected] 206-789-7945 [email protected]

Astronomical League: Bob Suryan, 206-789-0599, [email protected]

Webmaster: Paul Rodman, 425-889-8273, [email protected]

Club Telescopes & Equipment: Thomas Vaughan, 206-772-1282, [email protected]

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From the President’s Desk… Light Pollution

By Thomas Vaughan

Light Pollution

As I mentioned during the August meeting, our Dark Sky effort was prominently mentioned in the front-page story of the August 13th (Sunday) Everett Herald! If you didn't get a chance to read the article, you can find it here: http://www.heraldnet.com/ stories/06/08/13/100loc_a1starlight001.cfm

The article also points out the general problem of light pollution in Washington State. I'm sure all of us are painfully aware of how hard it is to find dark skies in the greater Seattle area. But I wasn't prepared for how fast dark skies are disappearing from the rest of the state.

A few weekends ago, a few of us camped out at a prospective dark sky site in Eastern Washington, between Ephrata and Moses Lake. You can see the report here: http:// www.wavepacket.net/tomva/dark-sky.html

As we set up our telescopes during the twilight hours, the site looked very promising! We had a clear 360 degree horizon, and only a few clouds were in the sky. But by midnight it was obvious that the site had too much light pollution for serious observing. Most of the western and south-eastern skies were completely washed out with lights from Ephrata and Moses Lake, respectively. Even looking north, where the skyglow was minimal, we couldn't do better than perhaps 5th magnitude stars.

We chalked that up to bad luck, and will continue our search for a dark site east of the mountains.

Over the Labor Day Weekend, I visited friends at their cabin along Hood Canal. I brought along my telescope, hoping for clear skies. I was fortunate: Saturday night was very clear, I didn't see a single cloud in the sky. I set up my telescope along the shore, and waited for the skies to get dark. However, the skies were even more light polluted than the prospective site in Eastern

Washington. I couldn't see better than 4th magnitude stars. There was a fair amount of

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light pollution from nearby houses and towns, but most of the glow (I'm sure) was from the Puget Sound metropolis of Seattle and Tacoma.

Even with the light pollution, I had a great hour or so of observing. Andromeda, the Ring Nebula, and M13 remain visible and spectacular. And I'm sure we'll be able to find a dark site for the club. But we also need to do our part to stop--and reverse!--the light pollution that is spreading across our state.

The best resource I know of is the International Dark Sky Association, at http:// www.darksky.org. They have a great list of approved light fixtures for practically any use. Do you have outdoor lights, or know someone who does? Visit the site and see if you can recommend a more sky-friendly fixture!

I myself am ordering a bunch of simple shields for my outside lights. Sure, it's just a drop in the pond as far as Seattle's light pollution goes, but it's a start.

Happy Observing-

-Thomas

Pictures from SAS Dark Sky Site...

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SAS August 2006 Club Meeting Minutes

Announcements: The date for the annual SAS banquet was announced as 1/13/07. A banquet chairperson is still needed.

Rattlesnake Lake access is no longer available due to security changes for the watershed. The turnaround is still available for observing however.

The Goldendale star party will be held 9/22 - 9/24 at Brooks Memorial State Park. Contact Karl Schroeder for information.

The SAS Dark Sky Site now has 32 members. An active search for property is underway and a weekend trip to a promising site near Ephrata is planned for a coming weekend.

The debate continues over the status of current and new planets.

Zach Drew provided a well done and lively “What’s Up” presentation which included information on the Ring Nebula, M13, M92, the binary pair with Alberio and epsilon Lyra.

Meeting Topic: This month’s topic was show and tell from club members. Maxine Nagel gave a report and showed pictures of the Table Mountain Star Party, Dave Irizarry showed the products of his efforts with his D50 camera, a expertly designed and constructed “barn door” camera mount was shown, Burley Packwood and Jim Peterson showed and talked about their homebuilt Dobsonians, Bruce Kelley demonstrated his new laser finder setup, Thomas Vaughan provided a fascinating galaxy simulation program.

Meeting was adjourned around 9:00PM. .

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Strange Space Pinwheels

Spotted [By Robin Lloyd]

The heart of one of the Milky Way galaxy's most massive star clusters harbors as many as five pin- wheels, a strange and relatively newly discovered type of stellar object, astronomers say.

Initially, scientists using the Hubble Space Telescope took a close look at the Quintu- plet Cluster, naming it after the five red massive and enigmatic stars found at its cen- ter. It was unclear if the stars, called "cocoon stars" for the dust surrounding them, were young or old.

Now, the Keck Observatory's 10-meter Keck I telescope on Mauna Kea in Hawaii, the world's biggest telescope, has shown that all five of the stars are approaching the ends of their lives and that at least two of the stars look like pinwheels, rotating around one another. The other stars also might be pinwheels, the scientists say, spewing out dust in a spiral arc in the same way a rotating lawn sprinkler creates a spiral of water.

"With five times greater resolution on the Keck Telescope, we could really focus in on the core of the star and drill deep down into the physics of these massive stars, finally answering the mystery of what these enigmatic cocoon stars are," said astrophysicist Peter Tuthill of the University of Sydney, Australia. Tuthill led the group that pub- lished the pinwheel images in the journal Science .

Pinwheels, or spirals, are quite rare and exotic in our galaxy, he said. "To find a whole little garden of them in this remote cluster was startling and beautiful," Tuthill told SPACE.com .

The dust plumes around the two pinwheel stars are typical of objects called colliding- wind binaries, he said. These stars, between 10 and 20 times the mass of our Sun and 10,000 to 100,000 times brighter than it, are exotic rarities found only among old mas- sive binaries.

The pinwheel discovery suggests that many of the very luminous stars in our galaxy, most of which are surrounded by dust, are actually massive binaries, not single stars,

Tuthill said.

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The five brightest Quintuplet stars lived fast and are dying young. They have burned off all their hydrogen and now are fueled by helium and fuse it into heavier elements, he said. In a binary system, such stars generate strong stellar winds that collide to cre- ate a lot of dust. The dust at the collision front between the stellar winds is carried around as the stars orbit, trailing dust that turns to create the pinwheel effect. For one of the pinwheels, the spiral measures 300 times the radius of Earth's orbit.

The binary in the pinwheels cannot be directly observed because it is shrouded in dust, but Tuthill and his colleagues William C. Danchi at NASA Goddard Spaceflight Center and John Monnier at the University of Michigan, recognized by the spiral tails that they were looking at a colliding wind binary because they had reported the first such spiral nebula in 1999 associated with the binary star system WR 104.

The Quintuplet Cluster is located near the center of our galaxy, 25,000 light years from Earth in the constellation Sagittarius, and is one of the most massive young star clus- ters known.

Massive binary star systems like those in the Quintuplet Cluster explode three times in their lives. There are two explosions when each of the pair separately undergoes a core-collapse supernova. Then a third explosion occurs as the two stars spiral into each other and merge. The Quintuplet stars imaged by the Keck are at the end of their nor- mal, stable lives, just before the final supernova explosion, Tuthill said. A gamma-ray burst will likely follow.

Supernovae are a phenomenon of high-mass stars, and the study of pinwheels and other massive stars will help astrophysicists better understand the subsequent super- novae explosions, he said. "To understand the supernovae we see, often at immense distances in the universe, it is very important to understand the precursor stars—these are what make supernovae and gamma-ray bursts happen," Tuthill said.

The finding also has implications for the number of stars and supernovae in the Milky Way. "The finding of these 'buried' binary stars, which are immediate supernova pre- cursors, tells us that sometimes there are two stars where we thought there to be only one," Tuthill said. "This has some influence on our census of the statistics of future su- pernovae in the galaxy."

Source: http://www.space.com/scienceastronomy/060904_mystery_monday.html

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September 2006 Sun Mon Tue Wed Thu Fri Sat 1 2

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UW Campus Amateur Observatory Telescope public viewing night Makers SIG Meeting

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Astrophot- ography/ Im- aging SIG Meeting

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SAS Meeting AstroFest AstroFest AstroFest

UW Campus Tiger Moun- Observatory tain/Poo Poo public Point Star Party viewing night

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SAS Board Green Lake Meeting Star Party

Paramount Park Star Party

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UW Campus Amateur Tele- Observatory scope Makers public viewing night SIG Meeting

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SAS Meeting Tiger Mountain Star UW Campus Party Observatory public viewing night

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SAS Board New Member Meeting Orientation

Green Lake Star Party Paramount Park Star Party

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Deadly Planets [ By Patrick L. Barry and Dr. Tony Phillips ]

About 900 light years from here, there's a rocky planet not much bigger than Earth. It goes around its star once every hundred days, a trifle fast, but not too different from a standard Earth-year. At least two and possibly three other planets circle the same star, forming a complete solar system.

Interested? Don't be. Going there would be the last thing you ever do.

The star is a pulsar, PSR 1257+12, the seething-hot core of a supernova that exploded millions of years ago. Its planets are bathed not in gentle, life-giving sunshine but instead a blistering torrent of X-rays and high-energy particles.

"It would be like trying to live next to Chernobyl," says Charles Beichman, a scientist at JPL and director of the Michelson Science Center at Caltech.

Our own sun emits small amounts of pulsar-like X-rays and high energy particles, but the amount of such radiation coming from a pulsar is "orders of magnitude more," he says. Even for a planet orbiting as far out as the Earth, this radiation could blow away the planet's atmosphere, and even vaporize sand right off the planet's surface.

Astronomer Alex Wolszczan discovered planets around PSR 1257+12 in the 1990s using Puerto Rico’s giant Arecibo radio telescope. At first, no one believed worlds could form around pulsars-it was too bizarre. Supernovas were supposed to destroy planets, not create them. Where did these worlds come from?

NASA’s Spitzer Space Telescope may have found the solution. Last year, a group of astronomers led by Deepto Chakrabarty of MIT pointed the infrared telescope toward pulsar 4U 0142+61. Data revealed a disk of gas and dust surrounding the central star, probably wreckage from the supernova. It was just the sort of disk that could coalesce to form planets!

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As deadly as pulsar planets are, they might also be hauntingly beautiful. The vapor- ized matter rising from the planets' surfaces could be ionized by the incoming radia- tion, creating colorful auroras across the sky. And though the pulsar would only ap- pear as a tiny dot in the sky (the pulsar itself is only 20-40 km across), it would be en- shrouded in a hazy glow of light emitted by radiation particles as they curve in the pulsar's strong magnetic field.

Wasted beauty? Maybe. Beichman points out the positive: "It's an awful place to try and form planets, but if you can do it there, you can do it anywhere."

More news and images from Spitzer can be found at http://www.spitzer.caltech.edu/ . In addition, The Space Place Web site features a cartoon talk show episode starring Mi- chelle Thaller, a scientist on Spitzer. Go to http://spaceplace.nasa.gov/en/kids/live/ for a great place to introduce kids to infrared and the joys of astronomy.

Artist’s concept of a pulsar and surround- ing disk of rubble called a “fallback” disk, out of which new planets could form.

This article was provided by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

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Space Bits

Giant Planet or Failed Star?

The Hubble Space Telescope has helped astronomers uncover an object right at the dividing line between stars and planets. The object, known as CHXR 73 B, weighs in at about 12 times the mass of Jupiter, and orbits a larger red dwarf star. The two objects are separated by 200 times the distance of the Earth to the Sun, so astronomers don’t think they both formed out of the same disk of gas and dust.

Link: http://www.universetoday.com/2006/09/07/giant-planet-or-failed-star/

Earth-Sized Planets are Probably Common

Of the many extrasolar planetary systems discovered so far, more than a third could contain Earth-like planets. This is according to a new study by scientists associated with NASA’s Center for Astrobiology. It was originally thought that Jupiter- sized planets should clear out their star systems as they form, but some new calculations show that they actually promote the formation of rocky planets - and even help pull in icy objects that deliver water to the inner planets.

Link: http://www.universetoday.com/2006/09/08/earth-sized-planets-are-probably- common/

Big Bang's Afterglow Fails Intergalactic 'Shadow' Test

The apparent absence of shadows where shadows were expected to be is raising new questions about the faint glow of microwave radiation once hailed as proof that the universe was created by a "Big Bang."

Link: http://www.sciencedaily.com/releases/2006/09/060905104549.htm

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Network of Small Telescopes Find a Big Planet

A network of amateur astronomers has discovered an extrasolar planet located 500 light years away. This incredible discovery was made using a technique that measures the brightness of thousands of stars, watching for a periodic dimming. In this case, the Jupiter-sized planet, TrES-2, orbits its host star every 2.5 days, dimming it by 1.5%. Although the planet was discovered by a 10cm telescope, followup observations were made using the 10 metre W.M. Keck Observatory on Mauna Kea in Hawaii.

Link: http://www.universetoday.com/2006/09/08/network-of-small-telescopes-find-a- big-planet/

Spitzer Spies Eternal Life Of Stardust

A new image from NASA's Spitzer Space Telescope is helping astronomers understand how stardust is recycled in galaxies. The cosmic portrait shows the Large Magellanic Cloud, a nearby dwarf galaxy

Link: http://www.sciencedaily.com/releases/2006/09/06090710400 2.htm

Hubble Captures A Rare Eclipse On Uranus

A new Hubble Space Telescope image shows a never-before-seen astronomical alignment of a moon traversing the face of Uranus, and its accompanying shadow. The white dot near the center of Uranus’ blue-green disk is the icy moon Ariel. The 700-mile- diameter satellite is casting a shadow onto the cloud tops of Uranus. To an observer on Uranus, this would appear as a solar eclipse, where the moon briefly blocks out the Sun as its shadow races across Uranus’s cloud tops.

Link: http://www.sciencedaily.com/releases/2006/09/060901190042.htm

Seattle Astronomical Society ‧131313

We promise you the sun, moon and stars and we deliver...

The Seattle Astronomical Society is an organization created and sustained by

people who share a common interest in the observational, educational, and

social aspects of amateur astronomy. Established in 1948, the SAS is a

diverse collection of over 200 individuals. A variety of programs and

activities is presented by the SAS throughout the year. Monthly meet-

ings feature speakers on a wide range of topics, from the Hubble

Space Telescope to electronic imaging to personal observing experi-

ences. The club holds public observing "star parties" at Green Lake

every month, dark sky observing parties outside Seattle, plus such ac-

tivities as meteor watches, public telescope and astronomy displays,

National Astronomy Day, and an annual Awards Banquet.

The Seattle Astronomical Society

PO Box 31746 Seattle, WA 98103-1746

SAS hotline: (206)-523-ASTR E-mail: [email protected]

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The Webfooted Astronomer is the monthly publication of the Seattle Astronomical Society (SAS). All opinions expressed herein are those of the contributors and not necessarily those of SAS. Advertising display rates: full page (5” x 8”) $30; less than full page: $5 per page inch (1” x 5”). Personal ads are published free to current paid members of the SAS. For all others, 10 cents per word, 50 word minimum charge. Submit article ideas to Editor, The Webfooted Astronomer, PO Box 31746, Seattle, WA 98103, or e-mail to [email protected].

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