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Journal of the Amateur Astronomers Association of New York May 2010 Volume 58 Number 5, ISSN 0146-7662

EYEPIECE
fields. Her findings show acceleration sites of lowenergy cosmic rays from the Sun get carried along by the magnetic field, medium energy cosmic rays from the Milky Way tend to accelerate in supernovae but get confined by the galactic magnetic field and high-energy cosmic rays (ultra galactic) are gamma-ray bursts or active galactic nuclei, aka blazers and quasars. Most neutrino experiments must address the flux of cosmic rays that bombard Earths surface, resulting in a continuous background of noise. To eradicate--or minimize--this problem, researchers have placed detectors deep under water (the Antares neutrino telescope lies under about 7,500 feet of water) or ice (the IceCube collaboration for observing neutrinos at predominantly low energies at the South Pole). Farrar called the telescope at the South Pole "the worlds best detector" because its a multi-purpose telescope that could provide an in-depth look at temperature variations in the ozone layer. She explained what happens as neutrinos pass through a thick layer of ice at amazing high speeds. They tend to slam into atoms, generating another type of elementary particle, primarily Farrar continued on page 8

A Neutrino's Encounter with a Terrestrial Detector
By Gerceida Jones
Dr. Glennys Farrar, professor of physics at NYU, heads the Center for Cosmology and Particle Physics there, and wants to use water towers on top of city buildings as a way to track the most mysterious particle in the universe, the elusive neutrino. In the AAAs lecture at the AMNH April 9 on "High -Energy Astrophysics with a Neutrino Telescope in New York City," Farrar outlined her ingenious idea to create a starter array of 1,000 stations inside existing water tanks to form a neutrino telescope capable of detecting high energy astrophysical neutrinos. She explained that neutrinos belong to particles called leptons which come in pairs; each neutrino has a charged partner. Most were created in the few seconds when the universe was composed of elementary particles. Additional neutrinos are produced in stars, such as our Sun, some via beta decay and some from supernova explosions. The only confirmed extraterrestrial neutrino sources are the Sun and supernova SN1987A. Farrar explained that since neutrinos are only weakly interactive with other particles, neutrino detectors must be very large in order to get a significant number of them. "They are extremely non-interacting and difficult to detect," she noted. Farrar said a 3,000 km2 detector would capture approximately 100 neutrinos. In theory, neutrinos can interact via the neutral current (exchange of a Z boson) or charged current (exchange of a W boson), weak interactions. Depending on the acceleration sites, solar and reactor neutrinos have enough energy to create electrons and most acceleratorbased neutrino beams can create muons and even a few taus. Farrar and her team use existing UHECR data to deduce properties of the source and the cosmic magnetic

Lee Baltin is Dead at 90
At press time, word was received of the death of Elias (Lee) Baltin in Florida at 90. Until several years ago, Lee was a longtime member of the AAA board of directors and treasurer. Among other activities, he supervised the clubs investments. More broadly, he was an active observer and was a constant source of advice and wisdom to club colleagues over several decades. More material on Lee will be in next months Eyepiece.


What's Up
By Tony Hoffman The Sky for May 2010
Venus Blazes in the Evening Sky. As the sky darkens, look to the west. That searingly bright orb is Venus. The "second rock from the Sun" blazes at magnitude -3.9 and moves from Taurus to Gemini this month. The best conjunction involving our sister world occurs at midmonth. On May 15, Venus will lie between the horns of Taurus, with a crescent Moon just below. Nearly Ringless Saturn. Saturn is well-placed for evening observers, though its rings are nearly out of view. Late in the month, theyll be inclined less than 2 degrees to our line of sight. Several of Saturns moons should be visible in a 4-inch telescope, while its largest moon, 8th magnitude Titan, can easily be seen in a smaller scope. Saturn lies near Beta Virginis and is of similar brightness to Virgos brightest star, Spica. Mars Soldiers On. Faded to first magnitude, Mars shines with but a pale shadow of last winters brilliance, but its still worth tracking as it moves from Cancer to Leo this month. Mars is now far enough away, and its disk small enough (~7 arc-seconds), that even a larger telescope will show little detail beyond perhaps the north polar cap. At the end of the month, Mars will lie 3 degrees from Regulus, which it outshines by a smidgen. Jupiter Rules the Predawn. Our solar systems largest planet rises at about 3 a.m. Shining at magnitude 2.2, Jupiter lies below the circlet of Pisces. A small scope will reveal Jupiters four Galilean moons. This month, the 6th magnitude planet Uranus lies in the same binocular field as Jupiter. At months end, the two worlds will lie just a degree apart. May May May May May 4:45 7:43 May May
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One Last Good View of Mars
By Joseph A. Fedrick
Mars was rapidly fading into the distance as Earth left it behind during March. Mars was dimming noticeably in the evening sky and its disk, as observed telescopically, was rapidly shrinking. I used my 6-inch f/9 Newtonian reflector and an eyepiece yielding about 150x to observe Mars March 24 between 8:30 and 9 p. m. A dark-grayish highland area, Syrtis Major, was near the center of the Martian disk. Most of the rest of the disk was a coral pink-tan hue. Just south of Syrtis Major, a low region, Hellas, was bright, almost white and probably was filled by a frosty haze indicating the arrival of autumn in that part of Mars, while the North Polar Cap had become much smaller as spring had been underway there. The Martian disk appeared gibbous as Earth approached quadrature with Mars. I slewed my Newtonian reflector toward Saturn after looking at Mars. Saturns disk was a tan-yellow hue and displayed faint brownish cloud belts. The ring system was less than 5 degrees from edgewise so the various parts of the rings--A ring, Cassini Division and B ring-were barely discernable. Mercury and Venus were barely above the rooftops of buildings to my west as I observed the planets from a street corner near my Bronx house at dusk on April 1. They were both visible in the same field of view in a pair of 10x50 binoculars, with Mercury being less than 4 degrees to the northwest (lower right) of Venus. Just before they sank behind the houses, Mercury became visible to my unaided eye. The following morning, Jupiter appeared just above the rooftops of Co-op City to my southeast at dawn. I used my 60mm refractor at 50x and 100x on April 10 to find Jupiters South Equatorial Belt had faded. In fact, Id observed the belt had already begun fading in late January, just before I lost Jupiter in the southwest at dusk. Images of Jupiters fading South Equatorial Belt during January can be found on Christopher Gos site on the Internet (http://jupiter.cstoneind.com/). Jupiter will soon be in conjunction with Uranus, so observing Jupiter will be especially interesting this year.

6 Last-quarter Moon at 12:15 a.m. 9 Moon lies near Jupiter. 13 New Moon at 9:04 p.m. 15, 16 Moon lies near Venus in evening sky. 20 Moon is at perigee, 229,742 miles from Earth, a.m.; Moon lies near Mars; First-quarter Moon at p.m. 23 Moon lies near Saturn. 27 Full Moon at 7:07 p.m


A Message from AAA President Richard Rosenberg
Hello, members: The AAA's annual meeting will take place Wednesday, May 19 at headquarters. There will be a buffet dinner at 6:30 and the meeting itself will begin at 7:30. A highlight will be the appearance of Jacqueline Hakim, the niece of Donald Gerard, a member of the club until his untimely death in 1943. Ms. Hakim will bring some memorabilia from that period. I hope all of you will come and meet your fellow members. Were continuing our efforts to make us to be better known in this tech-savvy world. Jason Kendall has us on Facebook, Tony Hoffman on Twitter, and were appearing in several on - and off-line magazines. One of the latter is KidCity, which has posted our summer observing schedule on its website and on Examiner. KidCity is also looking for parents what is one of your favorite outdoor "101 Anytime Summer Adventures." youre interested, send me your reply living in New York City to answer the question "On a beautiful summer day, things to do with your family?" Your quote will appear in an upcoming book I think early summer evenings qualify as much as "beautiful summer days." If and Ill forward it to the magazine.

Observing last month went off with a bang as AAA members set up their scopes all over the city. One highlight was resumption of observing at the High Line. Well be there every clear Tuesday until October. In July and September, well be at a new location, Fort Greene Park in Brooklyn. Check our website --www.aaa.org--or contact me for info on other special observing sessions at locations such as Pier 1 in Brooklyn. Our spring class began early in April and is still going on. Once again we have a large class, almost 30 students. I spoke for two weeks on the history of our solar system. Because I didnt cover everything and didnt have much time to answer questions, the presentation is now on our website (www.aaa.org/classes; click the "view slides" link). It is in PDF format so the movies won't show. Ill also devote some time to the solar system in our observers group and seminar meetings for the next few months. The first such meeting will be Tuesday, April 27 at 6:30 p. m. at headquarters, 120 Warren Street. All are welcome to attend. Rich Rosenberg, AAA President, president @aaa.org, (718) 522-5014

AAA's May 7 Lecture to Train a Lens on Astrophotography
Dr. Ruben Kier, a radiologist with a special interest in astrophotography, will wrap up the AAAs 2009-10 lecture series on Friday, May 7 when he discusses "Best Targets for Amateur Astrophotography and What They Reveal about our Universe." The free public lecture begins at 6:15 in the Kaufmann Theater of the AMNH. Kiers talk lecture will focus on the choice of celestial objects for astrophotography. In choosing his list of the 100 best astrophotography targets, he has sought to identify compositions that inspire the viewer. "Furthermore," he says, "the object should be bright enough to image with a backyard amateur telescope, an average CCD camera and fewer than three hours of total exposures. The target needs to be large enough to show detail and high enough in the sky to be captured from northern latitudes. More than a third of the targets can be framed with a second object to create a more dynamic image." Unlike the famous Messier, Hershel and Caldwell visual catalogs, Kiers list focuses specifically on the best objects for the amateur astrophotographer. But photographing objects is only part of the enjoyment, Kier notes. "Study of the images enriches the experience of visual astronomy. For example, star clusters show patterns of color that help us understand stellar evolution. Reflection and emission nebulae show comLecture continued on page 14
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Recent-Advances Seminar: Diverse Topics, Diverse Attendees
By Jason Kendall
The monthly recent-advances seminar April 8 at NYU attracted a diverse crowd, with many NYU students in attendance. Board member Gerceida Jones brought her intro students for a perspective on astronomy from people who are passionate about it. I had invited Bernie Klingleman, Dr. Laird Whitehill and a student named Bernadette Davis to speak. Bernie talked about energy. He observed that many people are unaware of how the word energy is used in a scientific context. Bernie provided a number of examples, from kinetic to quantum mechanical. Laird demonstrated Partiview, the free 3-D astronomical visualization software from the Hayden Planetarium. He had a good outline on how to operate it and see nearby stars. The script walked a new user who downloads the application through a treasure trove of astronomical data. Laird showed how to see planets, nearby galaxies and the Milky Ways structure indicators--open and globular clusters, and pulsars. There were satisfying wow moments, such as when a first-time observer sees Saturn through a scope, and all of Lairds copies of his script were taken home by attendees. Partiview is available for download at http://www.haydenplanetarium.org, and Ill send Lairds script to anyone who contacts me via e-mail (jkendall@moonbeam.net). Bernadette gave a promised report on rogue planets. In March, Id challenged her to bring in a report, and Gerceida helped her with her subject. She impressed other students with her willingness to jump into the fray, learn something new and present it. She discussed not only what shed had learned about planets that may have been expelled from their nascent solar systems by formation processes, but ably speculated about life on such a world, and what it would be like to "ride an exoplanet into interstellar space." What I liked best was how she wrapped up with questions she had from her reading. This is the point of the seminar: What we talk about spurs learning at home. Furthermore, Gerceida encouraged Bernadette to start an astronomy club at NYU, and shes agreed. I hope club members will help support this club by presenting material at the seminar.
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Im looking for 10-minute extemporaneous talks using a 10-slide PowerPoint or image set. The goal is to cover a single topic in the news. After the presentation, well discuss its importance, going to the web to help answer questions. Topics should have appeared in popular news media, NASA/ESA websites or refereed journal articles. E-mail me if youd like to present a topic. In March, this format encouraged a budding astronomy buff to return in April to share what shed learned. Join us May 13!

Fort Tryon Lights Shielded for AAA
By Anne Kiefer
To mark the 75th anniversary of Fort Tryon Park April 14, the Inwood Astronomy Project under AAA board member Jason Kendall persuaded the city parks department to cover streetlamps on the site, similar to the earlier light shutoff in Inwood Hill Park. More than 100 people gathered at Fort Tryon Park to celebrate the post-winter return of stargazing and the unveiling of a new telescope. Kendall brought an Obsession 15, one of the largest amateur telescopes available for public use in the city. He explained that since the scope isnt fully enclosed, ambient light can severely constrict its success. Attendees often stood in front of a troublesome light to aid viewing. Kendall showed Saturn in the scope. The rings and Titan, Tethys, Dione and Rhea were visible. He also pointed out the binary Alcor and Mizar in Ursa Major. Kendall and Bruce Kamiat found Mars and the neighboring Beehive Cluster. They discussed the difference between Obsession and binocular views. Kendall also worked to find what he called dark fuzzies, not visible to the naked eye. He located Messier 3, or the M3 globular cluster of cluster of some 500,000 stars more than 30,000 light-years away. The cluster looks like a fuzzy star in another scope, but in the Obsession 15 its clearly defined.


What to Know in Buying Scope Batteries and Accessories
By George Hripcsak
I was recently researching batteries to power telescope mounts and dew removers, and I thought I would share what I found. Most amateur astronomers use leadacid batteries to power their accessories. Although theyre heavy, theyre relatively inexpensive, they work at low temperatures and they last a long time. In choosing a battery, you need to select a voltage and a capacity. Most telescope accessories run at 12 volts, although a few mounts run at 18. A batterys capacity is expressed in amp-hours (Ah). If you add up the current in amps for all your accessories (usually stated in the manuals) and multiply by the number of hours youd like to run them in between charges, you get the Ah capacity you require. Youll generally want to double that number for your battery. Common sizes for astronomy are 7, 12, 17, 22 and 33 Ah. Do not use a car battery to power your telescope. That battery is built for the very high but brief current needed to start a car, but it becomes damaged if discharged too deeply. For example, I had to replace my car battery after someone left the car lights on for the third time. Nowadays, sealed lead-acid batteries based on an absorbed glass mat (AGM) are the best and most common option. They have replaced older gel cells, although they look similar externally. These batteries are built for deeper discharging, but they, too, will last longer if theyre only discharged to half their capacity. Most amateur astronomers buy a power supply that contains a lead-acid battery in a plastic enclosure with a charger, flashlight and often such accessories as a radio or air pump. Two examples are the Orion Dynamo and Celestron Power Tank for around $100. I dislike the chargers they come with. They take 10-35 hours to recharge the battery, and they must be disconnected before too long to avoid overcharging the battery. They also seem a little expensive for the junky accessories they come with. The Kendrick Power Pack is a high-quality power supply, but the price hits $200. I prefer to buy a separate battery and a high-quality charger. Modern lead-acid battery chargers are small, light, sophisticated and relatively inexpensive at $20. They recharge the battery in three stages. Add a $40 battery and you have nice system. B&B, CSB and Interstate are good battery brands. I've purchased batteries and accessories from PowerStream, ZBattery and BatterySpace on the Internet with good results. BatterySpace has a 12V Portable Power Kit, which includes a 12V 12Ah sealed lead-acid battery, a 3-amp charger and a shoulder bag for $70. It takes only a few hours to recharge the battery, and you can leave the charger connected indefinitely without hurting the battery. PowerStream has a similar 12V 22Ah package with a 2-amp charger for $100. That charger has a rejuvenation function that detects and removes sulphate deposits from worn batteries; it actually worked on two old batteries I have. Whatever you buy, make sure it has the right connector for your accessories, usually a car "cigarette lighter" adaptor. Youll want to recharge all your lead-acid batteries every two months even if you dont use them. Lead-acid batteries like to be topped off, and they slowly lose their charge. Letting the battery run down will shorten its life, and it wont be ready when you need it. For specialized applications, like highly portable telescopes, other battery types may work better. For example, Li-Ion batteries are much lighter than lead acid, but theyre much more expensive.

Obama Outlines New Space Goals
Speaking at the Kennedy Space Center April 15, President Obama unveiled plans to send astronauts to a nearby asteroid and ultimately to Mars in the mid-2030s. Obamas plan includes sion of the capsule-based to be scrapped under the Constellation Moon progr resurrecting a pared-down verOrion spacecraft initially slated Presidents cancellation of the am in February.

By 2025, the U. S. should be ready to test manned spaceships for deep-space exploration, vehicles capable of exploring beyond the Moon on the first-ever manned trip to an asteroid, Obama said.
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A Grand Tour of the Solar System, from the Moon to Pluto
By Evan Schneider
Where might NASA want to send astronauts to explore and live as we extend our reach into space? On April 6, AAA board member Jason Kendall provided insight to a Hayden audience. His tour began with the Moon, where water ice exists in abundance. This is the cornerstone of potential life on planets and their moons. But the Moon is no longer on NASAs agenda. So we begin our real tour with Mercury, with an 800-degree surface temperature and water ice at the poles, where temps drop to 200 below. The terrain is spectacular, with the Caloris Basin running 800 miles across one quarter of the diameter of the planet and mile-high cliffs. During Mercurys evolution, the basin was created by an impact that flooded the area with lava. Ridges and fractures formed when volcanic rock contracted and stretched as it settled under its own weight. Next stop: Venus. Again, we find an inhospitable environment. With the surface facing the Sun, theres a thick and highly pressurized atmosphere of carbon dioxide and nitrogen, as well as sulfur dioxide and sulfuric acid, and extensive volcanic plains. We arrived on Mars. Extensive data suggests Mars once contained a significant amount of water, and 2008 data identified water ice under the soil at the North Pole. Mars is our current focus for a visit. Among the planets interesting features is the Mariner Valley, a 4,000-milewide area 10 times deeper than the Grand Canyon and 20 times wider, with a rim at 25,000 feet. We flew over Mars and saw contrasts in digital data depicting highlands and lowlands. Ridges and surface features abound, creating exploration opportunities. But our solar neighborhood needs further exploration, so Jason flew us to Jupiter. Instead of a candidate to visit, we found a planet that wanted to be a star. Filled with an atmosphere of hydrogen and helium but not big enough to create its own nuclear fusion, the gas giant provides a visual spectacle, with a giant red spot and 64 moons, but no opportunity for surface exploration. But it has an interesting moon, Europa. In 2015, a
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joint NASA-ESA probe will visit Europa to observe what appears to be a surface of ice, and possibly water ice and liquid water below the surface. Theres evidence of salt staining and sulfide chimneys, which may yield discovery of life, even if in bacteria form. Earth has similar chimneys under oceans that harbor life. We then approach Saturn, following the path of Cassini. As a gas giant with winds of hundreds of miles per hour, Saturn would prevent exploration. But weve explored Saturns moon Titan, where Cassini/Huygens landed and observed lakes of methane gas and liquid. Scientists say there was pre-biotic chemistry, indicating conditions that may have been Earth-like 4 billion years ago. If warmer, Titan could have sustained life. We spin further around Saturn and stop at Enceladus, a big ball of water ice 300 miles across. Photographs show jets of salty water shooting through cracks in the ice 30 miles above the surface. Again, theres the possibility of a life-sustaining environment but no proof. We arrive at ice giant Uranus, a pale blue planet with rings of dark dust and rocks. Tilted 90 degrees on its side, its the third largest and fourth most massive planet in our solar system, composed of hydrogen and helium. This isnt a planet for a visit given its 500 mph winds. We reach Neptune. Voyager approached Neptune in 1989 amid a huge anticyclonic storm. The surface displayed a blue spot the diameter of Earth. This area gradually resolved itself as the atmosphere stabilized and the storm subsided. With its atmosphere of frozen methane, Neptune is not a candidate for a surface visit. Jason completed his tour with a brief review of Pluto, recently added to the dictionary as a verb "to be plutoed," or demoted. Although now classified as a dwarf planet, it retains NASAs interest through the New Horizons spacecraft speeding its way at 36,250 mph, currently about midway between Earth and Pluto, and due to arrive in 2015. Not much is known about Pluto due to its distance--light takes seven light-hours to reach Earth-but New Horizons promises to unlock some secrets.


The Future May Not Be Bleak--Let's Regreen Earth
By Greg Matloff
In 2010, we're all too familiar with the predicted effects of expanding human population upon our planets fragile ecosystem. Daily reports of diminishing resources, disappearing species, melting glaciers and increasing pollution fill the media. For both amateur and professional astronomers, light pollution has served as a sad reminder of the approaching "crunch" time. As is true for many others, I became aware of these problems during the 1970s, with the rise of environmental movements. There was a short glimmer of hope a few years later, when various astronomers, physicists and engineers outlined far-reaching plans to enhance humanitys resource base and effluent sink-- where we put garbage and pollution--by moving certain industries into cis-lunar (near-lunar) space. Since the space shuttle never lived up to its promise as a low-cost, routine method of accessing orbital space, these early concepts languished. But as discussed in my latest book, "Paradise Regained", co-authored with Les Johnson of NASAs Marshall Space Flight Center and artist C Bangs (SpringerCopernicus, $27.50), the future isnt necessarily bleak. As the world enters this critical environmental period, many national space agencies are developing interplanetary capabilities. It isnt impossible that some of these new technologies can help ease the Earth through the period of peak human population. Sometime around the middle of this century, human population is expected to peak around 9 billion. Must we expect an endless cycle of misery, war, famine and plague as people compete over limited resources? Not necessarily, says Arizona-based architect Palo Soleri. If we redesign living and office space so many human activities occur in thousand-foot high, space-habitat-like "arcologies," he believes, the environmental footprint of a large human population may be reduced to manageable levels. Since space-inspired hydroponic agriculture could be situated near the vertical cities, fossil-fuel requirements for freight transportation may be greatly reduced. The first prototype arcology is under construction and partially occupied in the Arizona desert. During the next few years, the Japanese space agency plans to launch and deploy the first test versions of space solar-power plants to beam energy to Earth. Although this technology may not be essential in the relatively underpopulated U. S., it may be an ultimate necessity for China and India. There's been much interest recently in technologies necessary to divert Earth-threatening asteroids. But if we have to alter the orbits of these objects, why not mine them? Material obtained may be very useful in creating an Earth-circling array of orbital solar-power plants. Even if we limit fossil-fuel use, enough carbon dioxide has been released that climate shifts may be inevitable. One suggested use of space technology is to disassemble an Earth-threatening asteroid to create a "sunshade" at an Earth-Sun Lagrange point to reduce solar insolation (input solar flux) by a few percent to compensate for the rise in greenhouse gases. The biggest uncertainty is the willingness of people to work together for common benefit. If we can overcome such difficulties as the conflict between globalists and tribalists, our technology may ultimately allow a regreening of Earth where all people (and many other species) can enjoy a comfortable and fulfilling lifestyle. We approached this project from different points of view. Les, a NASA manager, looked at the spaceenvironment interface as someone who implements space projects. I, an astronomer, was concerned with theoretical aspects of space-environment interaction. C, an artist whos been supported by NASA, elected to create chapter frontispieces by merging park, desert and garden scenes with NASA space imagery and photos of AMNH dioramas. C and I have created a short movie including this art, aided by video artist Kenn Bass. Its at www.youtube.com/user/BangsMatloff#play/all. ____________________________________________ AAA member Greg Matloff's "Paradise Regained" was published in January. He's assistant professor of physics at New York City College of Technology.
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Why Nebulae around Massive Stars Don't Disappear
The birth of the most massive stars--those 10-100 times the mass of the Sun--has posed a riddle for decades. Massive stars are dense enough to fuse hydrogen while theyre still gathering material from the gas cloud, so it was a mystery why their brilliant radiation doesnt heat infalling gas and blow it away. New simulations by researchers affiliated with the American Museum of Natural History, University of Heidelberg, the National Autonomous University of Mexico and the Harvard-Smithsonian Center for Astrophysics show that as the gas cloud collapses, it forms dense filamentary structures that absorb the stars radiation when it passes through them. One result: The surrounding heated nebula flickers like a candle flame. "To form a massive star, you need massive amounts of gas," says Mordecai-Mark Mac Low, curator in the astrophysics department at the museum. "Gravity draws that gas into filaments that feed the hungry baby stars." Stars form when huge clouds of gas collapse. Once the central density and temperature are high enough, hydrogen begins to fuse into helium and the star begins to shine. The most massive stars, though, begin to shine while the clouds are still collapsing. Their ultraviolet light ionizes the surrounding gas, forming a nebula with a temperature of 10,000 Celsius. This suggests growth of a massive star should taper off or even cease because surrounding gas should be blown away by the heating. First author Thomas Peters, a researcher at the Center of Astronomy at the University of Heidelberg, a former Annette Kade Fellow at the museum, and colleagues ran gas dynamical simulations on supercomputers at the Texas Advanced Computing Center and at the Leibniz and JЭlich Computing Centers in Germany. The results showed interstellar gas around massive stars doesnt fall evenly onto the star but instead forms filamentary concentrations because the amount of gas is so great gravity causes it to collapse locally while falling to the star. The local areas of collapse form spiral filaments. When the massive star passes through them, they absorb their ultraviolet radiation, shielding the surrounding gas. This shielding explains not only how gas can continue
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falling in, but why the ionized nebulae observed with radio telescopes are so small: The nebulae shrink again as they are no longer ionized, so that over thousands of years, the nebula appears to flicker, almost like a candle. "These ionized nebulae were just thought to be expanding bubbles of hot gas, and the measured size of these bubbles was used by observers to infer the age of its central star," Peters says. "Our results are of particular importance because the simulations show there is, in fact, no direct relation between the size of the nebula and the age of the massive star, so long as the star is still growing. This is the case over a significant fraction of the total lifetime of a massive star." Farrar continued from page 1 muons. These particles, in turn, emit light as they pass through the ice. The photon detector making up IceCube detects them, and measures several properties before they completely decay. The problem with this particular scope is that the