COMING EVENTS Public Observing
Saturday, July 2 Bloomington East Park
9:00 PM
Post-Band Concerts Wed. July 13
South Park - West 9:00 PM
President
Rick Heschmeyer [email protected]
University Advisor Dr. Bruce Twarog [email protected]
Webmaster Gary Webber
Observing Clubs Doug Fay
Report from the Officers: After a seemingly end-less string of bad weather, our luck finally came out on the plus side as our last two public observing events after the South Park Band concerts went through without a hitch. The observing drew some enthusiastic par-ticipants, as illustrated in the photo on the left from June 15. There is a holiday weekend
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Volume 37 Number 07 JULY 2011
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INSIDE THIS ISSUE
Outreach Download (cont.) 2
Most Distant Quasar 3
NASA Space Place 4
Flames of Betelgeuse 5
Green Ring Nebula 6
Pandora’s Cluster 7
SN1987 A(gain) 8
Green Ring (continued) 8
Pandora (continued) 9
Galaxies- Awake or Asleep 9
Galaxies (continued) 10
From the Astronomical League
What are Outreach Downloads? John Goss
“What telescope should I buy?” “How can I learn my way around the night sky?”
“What can I see with my telescope?”
Outreach is all about connecting with the public. The Astronomical League has devel-oped a series of downloadable outreach materials that do just that. They help answer questions commonly posed by the public and help spark curiosity about our fascinat-ing hobby. These materials can be displayed at club activities and astronomy events such as Astronomy Day, school sessions, star parties and amateur conventions, and club meetings.
Simply download the pdf files on a CD and take it to a local printing shop (e.g., Kin-kos). Many shops will print the materials in black and white on 20 lb paper for as low as $0.75 per square foot. Color printing will likely cost substantially more, which is why most layouts are designed in black and white. At some shops, the maximum paper width is 36 inches with no restriction on length. Indeed, banner posters many feet long can be printed. If your home printer allows banners, they can be printed on banner or “doodle” paper found in craft stores (e.g., Michael’s).
The aspect ratio (width to height) is given in the description of each poster. There-fore, the printed size can be any proportion of that ratio with no unintentional cropping
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A Galactic Greeting to New Members
CHUCK WEHNER & MEGAN WITHIAM
About the Astronomy Associates of Lawrence
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The club is open to all people interested in sharing their love for astronomy. Monthly meetings are typically on the second Fri-day of each month and often feature guest speakers, presentations by club members, and a chance to exchange amateur as-tronomy tips. Approximately the last Sunday of each month we have an open house at the Prairie Park Nature Center. Periodic
star parties are scheduled as well. For more information, please contact the club officers:our president, Rick Heschmeyer at [email protected], our webmaster, Gary Webber, at [email protected], or our faculty advisor, Prof. Bruce Twarog at
[email protected]. Because of the flexibility of the schedule due to holidays and alternate events, it is always best to check the Web site for the exact Fridays and Sundays when events are scheduled. The information about AAL can be found at
http://www.ku.edu/~aal. Copies of the Celestial Mechanic can also be found on the web at
http://www.ku.edu/~aal/celestialmechanic
presentation planned for Saturday evening, July 2, at Clinton Lake at the Bloomington East Campground. Rick, as usual, is getting this organized, so please contact him if you are interested in helping. As of Friday, the weather doesn’t look promis-ing, but that can change. Last month we highlighted some star parties in the mid-states region that might draw the attention of some of our more ad-venturous members. This month we should point out that the Stellafane Convention takes place in Springfield VT from July 28-31. The Stellafane Convention may well be the most famous gathering of amateurs with a love of tech-nology development, i.e. Stellafane is a gathering of amateur telescope makers. The Convention was started in 1926 to give amateur telescope makers an opportunity to gather to show off their creations and teach each other telescope making and mirror-grinding techniques. All telescopes, commercial and homemade are wel-come. If you have made your own telescope, you are strongly encouraged to display it in the telescope fields near the Pink Clubhouse. If you wish, you can enter your homemade telescope in the mechanical and/or optical competition. There are also mirror-grinding and telescope-making demonstrations, technical lectures on tele-scope making and the presentation of awards for telescope design and craftsmanship. Vendor displays and the retail sale of commercial products are not permitted. Those of you who read Percival’s Planet may recall that this Convention serves as a backdrop for the opening introduction of the retired Clyde Tombaugh to the novel’s audience, an appropriate initiation given Clyde’s well-known penchant for building his own telescopes. Any suggestions for improving the club or newsletter are always welcome. Have a great holiday.
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as long as the maximum width doesn’t exceed 36 inches. For instance, a poster with a 2:3 aspect ratio that is originally de-signed to be 20 inches by 30 inches can also be enlarged to 24 inches by 36 inches.
Some posters feature questions with multiple choice answers. The correct answers lie hidden under a liftable flap made from a stiff card taped to the poster. The Spring Sky (http://www.astroleague.org/files/outreach/SpringSky.pdf) In a guided tour consisting of nine easy steps, the late April or early May sky is described. The poster features a large all-sky map showing the ecliptic, the Milky Way, and stars down to 4th magnitude. The Need for Telescopes (http://www.astroleague.org/files/outreach/NeedForTelescopes.pdf) Banner: 8 1/2 x 44 inches. Can be printed in color on a home computer Directly compares the apparent sizes of the moon, the bright planets, and a typical field of view of a low-powered telescope. Our Unnatural Night (http://www.astroleague.org/files/outreach/OurUnnaturalNight.pdf) Aspect ratio: 3:4 Original design size: 36 inches x 48 inches Requires a liftable "Answer Flap" to conceal the answers to the nine questions posed. Simply tape (masking tape) the top edge of the flap to the top edge of the answer box. Mounts to a 36 inch x 48 inch inexpensive tri-fold display board. Describes how problem of light pollution affects us all. The Autumn Sky (http://www.astroleague.org/files/outreach/FallSky.pdf) Aspect ratio: 2:3 In a guided tour consisting of eight easy steps, the late September or early October sky is described. The poster features a large all-sky map showing the ecliptic, the Milky Way, and stars down to 4th magnitude.
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Universe's Most Distant Quasar Found, Powered by Massive Black Hole A team of European astronomers has used the European Southern Observatory's Very Large Telescope and a host of other telescopes to discover and study the most distant quasar found to date. This brilliant beacon, powered by a black hole with a mass two billion times that of the Sun, is by far the brightest object yet discovered in the early Universe. The results appear in the June 30, 2011, issue of the journal Nature.
"This quasar is a vital probe of the early Universe. It is a very rare object that will help us to understand how supermas-sive black holes grew a few hundred million years after the Big Bang," says Stephen Warren, the study's team leader.
Quasars are very bright, distant galaxies that are believed to be powered by supermassive black holes at their centres. Their brilliance makes them powerful beacons that may help to probe the era when the first stars and galaxies were forming. The newly discovered quasar is so far away that its light probes the last part of the reionization era [1].
The quasar that has just been found, named ULAS J1120+0641 [2], is seen as it was only 770 million years after the Big Bang (redshift 7.1, [3]). It took 12.9 billion years for its light to reach us.
Although more distant objects have been confirmed (such as a gamma-ray burst at redshift 8.2 and a galaxy at redshift 8.6), the newly discovered quasar is hundreds of times brighter than these. Amongst objects bright enough to be stud-ied in detail, this is the most distant by a large margin.
The next most-distant quasar is seen as it was 870 million years after the Big Bang (redshift 6.4). Similar objects fur-ther away cannot be found in visible-light surveys because their light, stretched by the expansion of the Universe, falls mostly in the infrared part of the spectrum by the time it gets to Earth. The European UKIRT Infrared Deep Sky Survey (UKIDSS) which uses the UK's dedicated infrared telescope [4] in Hawaii was designed to solve this problem. The team of astronomers hunted through millions of objects in the UKIDSS database to find those that could be the long-sought distant quasars, and eventually struck gold.
"It took us five years to find this object," explains Bram Venemans, one of the authors of the study. "We were looking for a quasar with redshift higher than 6.5. Finding one that is this far away, at a redshift higher than 7, was an exciting surprise. By peering deep into the reionization era, this quasar provides a unique opportunity to explore a 100-million-year window in the history of the cosmos that was previously out of reach."
The distance to the quasar was determined from observations made with the FORS2 instrument on ESO's Very Large Telescope (VLT) and instruments on the Gemini North Telescope [5]. Because the object is comparatively bright it is possible to take a spectrum of it (which involves splitting the light from the object into its component colors). This tech-nique allowed the astronomers to find out quite a lot about the quasar.
These observations showed that the mass of the black hole at the centre of ULAS J1120+0641 is about two billion times that of the Sun. This very high mass is hard to explain so early on after the Big Bang. Current theories for the growth of supermassive black holes predict a slow build-up in mass as the compact object pulls in matter from its surroundings.
"We think there are only about 100 bright quasars with redshift higher than 7 over the whole sky," concludes Daniel Mort-lock, the leading author of the paper. "Finding this object re-quired a painstaking search, but it was worth the effort to be able to unravel some of the mysteries of the early Uni-verse."
This artist’s impression shows how ULAS J1120+0641, a very distant quasar pow-ered by a black hole with a mass two billion times that of the Sun, may have looked. This quasar is the most distant yet found and is seen as it was just 770 million years after the Big Bang. This object is by far the brightest object yet discovered in the early Universe. (Credit: ESO/M. Kornmesser)
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Finding Planets among the Stars by Dr. Tony Phillips
Strange but true: When it comes to finding new extra-solar planets, or exoplanets, stars can be an incredible nuisance.
It’s a matter of luminosity. Stars are bright, but their planets are not. Indeed, when an astronomer peers across light years to find a distant Earth-like world, what he often finds instead is an annoying glare. The light of the star itself makes the star's dim planetary system nearly impossible to see. Talk about frustration! How would you like to be an astronomer who's constantly vexed by stars?
Fortunately, there may be a solution. It comes from NASA's Galaxy Evolution Explorer, an ultraviolet space telescope or-biting Earth since 2003. In a new study, researchers say the Galaxy Evolution Explorer is able to pin-point dim stars that might not badly outshine their own planets.
“We've discovered a new technique of using ultraviolet light to search for young, low-mass stars near the Earth,” said David Rodriguez, a graduate student of astronomy at UCLA, and the study's lead author. “These M-class stars, also known as red dwarfs, make excellent tar-gets for future direct imaging of exoplanets.” Young red dwarfs produce a telltale glow in the ultraviolet part of the electromagnetic spectrum that Gal-axy Evolution Explorer can sense. Because dwarf stars are so numer-ous—as a class, they account for more than two-thirds of the stars in the galaxy—astronomers could reap a rich bounty of targets.
In many ways, these stars represent a best-case scenario for planet hunting. They are close and in clear lines-of-sight, which generally makes viewing easier. Their low mass means they are dimmer than heavier stars, so their light is less likely to mask the feeble light of a planet. And because they are young, their planets are freshly formed, and thus warmer and brighter than older planetary bodies.
Astronomers know of more than five hundred distant planets, but very few have actually been seen. Many exoplanets are detected indirectly by means of their “wobbles”—the gravitational tugs they exert on their central stars. Some are found when they transit the parent star, momentarily dimming the glare, but not dimming it enough to reveal the planet itself.
The new Galaxy Evolution Explorer technique might eventually lead to planets that can be seen directly. That would be good because, as Rodriguez points out, “seeing is believing.”
And it just might make astronomers feel a little better about the stars.
The Galaxy Evolution Explorer Web site at http://www.galex.caltech.edu describes many of the other discoveries and ac-complishments of this mission. And for kids, how do astronomers know how far away a star or galaxy is? Play “How Old do I Look” on The Space Place at http://spaceplace.nasa.gov/whats-older and find out!
This article was provided by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.
Exoplanets are easier to see directly when their star is a dim, red dwarf.
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Flames of Betelgeuse: New Image Reveals Vast Nebula Around Famous Supergiant Star
Science Daily Using the VISIR instrument on the European Southern Observatory's Very Large Telescope (VLT), astronomers have imaged a complex and bright nebula around the supergiant star Betelgeuse in greater detail than ever before. This structure, which resembles flames emanating from the star, is formed as the behemoth sheds its material into space.
Betelgeuse, a red supergiant in the constellation of Orion, is one of the brightest stars in the night sky. It is also one of the biggest, being almost the size of the orbit of Jupiter -- about four and half times the diameter of Earth's orbit. The VLT image shows the surrounding nebula, which is much bigger than the supergiant itself, stretching 60 billion kilometers away from the star's surface -- about 400 times the distance of Earth from the Sun.
Red supergiants like Betelgeuse represent one of the last stages in the life of a massive star. In this short-lived phase, the star increases in size, and expels material into space at a tremendous rate -- it sheds immense quantities of material (about the mass of the Sun) in just 10,000 years.
The process by which material is shed from a star like Betelgeuse involves two phenomena. The first is the forma-tion of huge plumes of gas (although much smaller than the nebula now imaged) extending into space from the star's surface, previously detected using the NACO instrument on the VLT [1]. The other, which is behind the ejec-
tion of the plumes, is the vigorous up and down movement of giant bubbles in Betelgeuse's at-mosphere -- like boiling water circulating in a pot.
The new results show that the plumes seen close to the star are probably connected to structures in the outer nebula now imaged in the infrared with VISIR. The nebula cannot be seen in visible light, as the very bright Betelgeuse completely outshines it. The irregular, asymmetric shape of the material indicates that the star did not eject its material in a symmetric way. The bubbles of stel-lar material and the giant plumes they originate may be responsible for the clumpy look of the nebula.
The material visible in the new image is most likely made of silicate and alumina dust. This is the same material that forms most of the crust of Earth and other rocky planets. At some time in the distant past, the silicates of Earth were formed by a massive (and now extinct) star simi-lar to Betelgeuse.
In this composite image, the earlier NACO obser-vations of the plumes are reproduced in the cen-tral disc. The small red circle in the middle has a diameter about four and half times that of Earth's orbit and represents the location of Betelgeuse's visible surface. The black disc corresponds to a very bright part of the image that was masked to allow the fainter nebula to be seen. The VISIR images were taken through infrared filters sensi-tive to radiation of different wavelengths, with blue corresponding to shorter wavelengths and red to longer. The field of view is 5.63 x 5.63 arcseconds.
This picture of the dramatic nebula around the bright red super-giant star Betelgeuse was created from images taken with the VISIR infrared camera on ESO's Very Large Telescope (VLT). This structure, resembling flames emanating from the star, forms because the behemoth is shedding its material into space. The earlier NACO observations of the plumes are repro-duced in the central disc. The small red circle in the middle has a diameter about four and half times that of the Earth's orbit and represents the location of Betelgeuse's visible surface. The black disc corresponds to a very bright part of the image that was masked to allow the fainter nebula to be seen. (Credit: ESO/P. Kervella)
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In the Blackest Night, a Green Ring Nebula This glowing emerald nebula seen by NASA's Spitzer Space Telescope is reminiscent of the glowing ring wielded by the superhero Green Lantern. In the comic books, the diminutive Guardians of the Planet "Oa" forged his power ring, but astronomers believe rings like this are actually sculpted by the powerful light of giant "O" stars. O stars are the most massive type of star known to exist.
Named RCW 120, this region of hot gas and glowing dust can be found in the murky clouds encircled by the tail of the constellation Scorpius. The ring of dust is actually glowing in infrared colors that our eyes cannot see, but show up brightly when viewed by Spitzer's infrared detectors. At the center of this ring are a couple of giant stars whose intense ultraviolet light has carved out the bubble, though they blend in with other stars when viewed in infrared.
The green ring is where dust is being hit by winds and intense light from the massive stars. The green color represents infrared light coming from tiny dust grains called polycyclic aromatic hydrocarbons. These small grains have been de-
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Abell 2744: Pandora's Cluster Revealed
One of the most complicated and dramatic collisions between galaxy clusters ever seen is captured in this new composite image. This collision site, known officially as Abell 2744, has been dubbed "Pandora's Cluster" because of the wide variety of different structures seen. Data from NASA's Chandra X-ray Observatory are colored red, showing gas with temperatures of millions of degrees. In blue is a map showing the total mass concentration (mostly dark matter) based on data from the Hubble Space Telescope (HST), the European Southern Observatory's Very Large Telescope (VLT), and the Japanese Su-baru telescope. Optical data from HST and VLT also show the constituent galaxies of the clusters.
The "core" region shows a bullet-shaped structure in the X-ray emitting hot gas and a separation between the hot gas and the dark matter. (As a guide, local peaks in the distribution of hot gas and overall matter in the different regions are shown with red and blue circles respectively). This separation occurs because electric forces between colliding particles in the clouds of hot gas create a friction that slows them down, while dark matter is unaffected by such forces.
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stroyed inside the bubble. The red color inside the ring shows slightly larger, hotter dust grains, heated by the mas-sive stars.
This bubble is far from unique. Just as the Guardians of "Oa" have selected many beings to serve as Green Lanterns and patrol different sectors of space, Spitzer has found that such bubbles are common and can be found around O stars throughout our Milky Way galaxy. The small objects at the lower right area of the image may themselves be similar regions seen at much greater distances across the galaxy.
Rings like this are so common in Spitzer's observations that astronomers have even enlisted the help of the public to help them find and catalog them all. Anyone interested in joining the search as a citizen scientist can visit "The Milky Way Project," part of the "Zooniverse" of public astronomy projects, at http://www.milkywayproject.org/.
RCW 120 can be found slightly above the flat plane of our galaxy, located toward the bottom of the picture. The green haze seen here is the diffuse glow of dust from the galactic plane.
This is a three-color composite that shows infrared observations from two Spitzer instruments. Blue represents 3.6-micron light and green shows light of 8 microns, both captured by Spitzer's infrared array camera. Red is 24-micron light detected by Spitzer's multiband imaging photometer.
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New Supernova Remnant Lights Up Astronomers using NASA's Hubble Space Telescope are witnessing the unprecedented transition of a supernova to a supernova remnant, where light from an exploding star in a neighboring galaxy, the Large Magellanic Cloud,
reached Earth in February 1987. Named Supernova 1987A, it was the closest supernova explosion witnessed in almost 400 years. The supernova's close prox-imity to Earth has allowed astronomers to study it in detail as it evolves. Now, the super-nova debris, which has faded over the years, is brightening. This means that a differ-ent power source has begun to light the debris. The debris of
SN 1987A is beginning to impact the surrounding ring, creating powerful shock waves that generate X-rays observed with NASA's Chandra X-ray Observatory. Those X-rays are illuminating the supernova debris and shock heating is making it glow in visible light. The results are being reported in an issue of the journal Nature by a team including Robert Kirshner of the Harvard-Smithsonian Center for Astrophysics (CfA), who leads a long-term study of SN 1987A with Hubble. Since its launch in 1990, the Hubble telescope has provided a continuous record of the changes in SN 1987A.
In the Northwest ("NW") region, a much larger separation is seen between the hot gas and the dark matter. Surprisingly, the hot gas leads the "dark" clump (mostly dark matter) by about 500,000 light years. This unusual configuration may require a slingshot scenario, as suggested previously by scientists, to fling the hot gas ahead of the dark matter during an earlier inter-action. In the North ("N") and the West ("W") two additional examples of hot gas separated from dark matter may be visible. The latter appears to exhibit the largest separation seen to date between hot gas and dark matter.
The authors of this study retraced the de-tails of the collision, and deduce that at least four different galaxy clusters coming from a variety of directions were involved. To un-derstand this history, it was crucial to map the positions of all three types of matter in Abell 2744. Although the galaxies are bright, they make up less than 5% of the mass in Abell 2744. The rest is hot gas (around 20%) visible only in X-rays, and dark matter (around 75%), which is completely invisible.
Dark matter is particularly elusive as it does not emit, absorb or reflect light, but only makes itself apparent through its gravita-tional attraction. To pinpoint the location of this mysterious substance the team used a phenomenon known as gravitational lens-ing. This is the bending of light rays from distant galaxies as they pass through the gravitational field present in the cluster. The result is a series of telltale distortions in the images of galaxies in the background of optical observations. By carefully plotting the way that these images are distorted, a map is constructed of where the mass -- and hence the dark matter -- actually lies (shown in blue).
Galaxy clusters are the largest gravitation-ally bound objects in the Universe and have
become powerful tools in cosmology studies. Further studies of Abell 2744 may provide a deeper understanding of the way that these important objects grow and provide new insight into the properties of dark matter.
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Astronomers Discover That Galaxies Are Either Asleep or Awake (Note - Greg Rudnick of KU is a co-author of this research paper.) Astronomers have probed into the distant universe and discovered that galaxies display one of two distinct behaviors: they are either awake or asleep, actively forming stars or are not forming any new stars at all.
Scientists have known for several years that galaxies in the nearby universe seem to fall into one of these two states. But a new survey of the distant universe shows that even very young galaxies as far away as 12 billion light years are either awake or asleep as well, meaning galaxies have behaved this way for more than 85 percent of the history of the universe. (Looking at galaxies farther away is like looking back in time when they were much younger, because of how long it takes the light they emit to reach us here on Earth.)
"The fact that we see such young galaxies in the distant universe that have already shut off is remarkable," said Kate Whitaker, a Yale University graduate student and lead author of the paper, which is published in the June 20 online edition of the Astrophysical Journal.
In order to determine whether the galaxies were asleep or awake, Whitaker and her colleagues fabricated a new set of fil-ters, each one sensitive to different wavelengths of light, which they used on a 4-meter Kitt Peak telescope in Arizona. They
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AAL Astronomy Associates of Lawrence
University of Kansas Malott Hall 1251 Wescoe Hall Dr, Room 1082 Lawrence, KS 66045-7582
Celestial Mechanic JULY 2011
spent 75 nights peering into the distant universe and collecting light from 40,000 galaxies ranging in dis-tance from the nearby universe out to 12 billion light years away. The resulting survey is the deepest and most complete ever made at those distances and wavelengths of light.
The team deciphered the galaxies' dual behavior based on the color of the light they emit. Because of the physics of star formation, active, wakeful galax-ies appear bluer, while the light emitted by passive, sleepy galaxies tends toward the redder end of the spectrum.
The researchers found that there are many more active galaxies than passive ones, which agrees with the current thinking that galaxies start out ac-tively forming stars before eventually shutting down.
"We don't see many galaxies in the in-between state," said Pieter van Dokkum, a Yale astronomer and another author of the paper. "This discovery
shows how quickly galaxies go from one state to the other, from actively forming stars to shutting off."
Whether the sleeping galaxies have completely shut down remains an open question, Whitaker said. However, the new study suggests the active galaxies are forming stars at rates about 50 times greater than their sleepy counterparts.
"Next, we hope to determine whether galaxies go back and forth between waking and sleeping or whether they fall asleep and never wake up again," van Dokkum said. "We're also interested in how long it takes galaxies to fall asleep, and whether we can catch one in the act of dozing off."
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Bluer galaxies are actively "awake" and forming stars, while redder galaxies have shut down and are "asleep." (Credit: NASA, ESA, S. Beckwith (STScI) and the HUDF team)
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