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COMING EVENTS Public Observing
Sunday October 28 Prairie Park Nature Center
8:30 PM Monthly Meeting
Friday Oct. 19 7:00 PM, 3139 WESCOE
Webelo Astronomy Night
President Rick Heschmeyer
[email protected] University Advisor Dr. Bruce Twarog [email protected]
Webmaster Howard Edin
[email protected] Observing Clubs
Doug Fay [email protected]
ALCOR William Winkler
Report from the Officers: The first meeting of the semester was held two weeks ago and those of you who attended know why the picture at right is shown. If you can move back away from the image or blur your vi-sion, you may find that the picture isn’t who you think it is. The effect is tied to the way our vision and our brain proc-ess high and low frequency structure and supplies a nice example of the value of Fourier analysis, a key element in making sense of the extraordinary flood of data from the Kepler space craft. For the month of October, as we do every year, we will forego our usual meeting and replace it with our public education event, Webelo Astronomy night. Rick has been the
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Volume 38 Number 10 October 2012
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INSIDE THIS ISSUE
Dark Sky (continued) 2
Kepler’s SN Remnant 3
NASA Space Place 4
Webelo Poster 5
The Odd Couple 6
Dark Sky (continued) 6
WISE Uncovers BHs 7
Kepler’s SN (continued) 8
WISE (continued) 8
Spitzer = Earth Size Planet 9
Spitzer (continued) 10
Dark Sky Nirvana: The Okie‐Tex Star Party By Howard Edin, Astronomy Associates of Lawrence
Located in the northwest corner of the Oklahoma panhandle is the Black Mesa area; where millions of years ago rivers of lava covered the ground and have since, slowly weathered into these mesas. Here you will find the tiny town of Kenton with a popu-lation of 16. Every year, around the end of summer, hundreds of people descend on this area for the Okie-Tex star party. For the thirteenth time I spent a week enjoying the night sky with fellow astronomy enthusiasts.
The Oklahoma City Astronomy club has organized the Okie-Tex star party for 29 years. For the past 14 years the star party has been held at a site called Camp Billy Joe, located just east of Kenton. This is a remote site; cell phones don’t work1 and its 30 miles to the nearest gas station. There’s virtually no light pollution, the skies are rated Bortle class 1.
The chance to experience an incredible night sky is the reason I drive the distance. I’m not alone, around me were those from New Jersey, Virginia, Ontario, Wisconsin, and Texas. All the preparation and travel are worth it the moment darkness arrives. The Milky Way blazes a path from overhead to the horizon; its dark lanes prominent and well defined. Experiencing a good clear night here is breathtaking. This is ex-actly how it started out this year. Despite all the planning every star party has one unpredictable and uncontrollable element: the weather. This party started off with two clear nights followed by two partly cloudy nights. For deep sky observers the partly cloudy nights are not a terri-ble inconvenience, perhaps not the best of conditions but workable. As an imager I had a several nights cut short by troublesome clouds. Yet even the clouds can fasci-nate me here, for they are black and blot out the Milky Way like a dark nebula.
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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: president, Rick Heschmeyer at [email protected]; webmaster, Howard Edin, at [email protected]; AlCor William Winkler, at
[email protected]; or 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://groups.ku.edu/~astronomy
Copies of the Celestial Mechanic can also be found on the web at http://groups.ku.edu/~astronomy/celestialmechanic
lead on this for the indoor education but, as always, we need people with telescopes set up outside of Wescoe to allow the few hundred scouts/people to get a glimpse of the night sky, weather permitting. So, if you can bring a telescope for viewing to set up, it would help a great deal. The more scopes we have, the more objects we can view faster. Please let Rick know if you can come by. The major local event of August was the launch of the RBSP satellite. KU Professor Emeritus Tom Armstrong, with a distinguished career in Space Physics, is running the Science Opera-tions Center for RBSPICE, one of the four key instruments on the satellite, from Lawrence through his tech company. Tom will be our speaker for the Nov. 9 meeting. The next Sunday public observing session at the Prairie Park Nature Center will begin at 8 :30 PM, Sunday, Oct. 28. The switch off Daylight Savings Time occurs the following weekend. Any suggestions for improving the club or the newsletter are always welcome.
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On Wednesday evening it began raining and con-tinued throughout the night. With the drought this season I didn’t hear a single person com-plain. The moisture was welcome; conditions had so far been hot, dry and windy. The rain settled the dust and marked a change in the weather pattern. The warmer nights early in the week were replaced by cooler air behind the storm front. Thursday night the sky was partly cloudy as the storm moved east. Conditions were actually very usable if one was ready for the dew. That I was, my dew heaters were attached and run-ning at sunset. Others less prepared had to surrender to moisture problems later in the night.
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Let the 29th annual Okie-Tex star party begin! Looking south as darkness arrives, Saturday September 8th
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Kepler's Supernova Remnant: Was Kepler's Supernova Unusually Powerful? In 1604, a new star appeared in the night sky that was much brighter than Jupiter and dimmed over several weeks. This event was witnessed by sky watchers including the famous astronomer Johannes Kepler. Centuries later, the debris from this exploded star is known as the Kepler supernova remnant.
Astronomers have long studied the Kepler supernova remnant and tried to determine exactly what happened when the star exploded to create it. New analysis of a long observation from NASA's Chandra X-ray Observatory is providing more clues. This analysis suggests that the supernova explosion was not only more powerful, but might have also occurred at a greater distance, than previously thought.
This image shows the Chandra data derived from more than 8 days worth of observing time. The X-rays are shown in five colors from lower to higher energies: red, yellow, green, blue, and purple. These various X-ray slices were then combined with an optical image from the Digitized Sky Survey (light yellow and blue), showing stars in the field.
Previous analysis of this Chandra image has determined that the stellar explosion that created Kepler was what astronomers call a "Type Ia" supernova. This class of supernovas occurs when a white dwarf gains mass, either by pulling gas off a companion star or merging with another white dwarf, until it becomes unstable and is de-stroyed by a thermonuclear explosion. Unlike other well-known Type Ia supernovas and their remnants, Kepler's debris field is being strongly shaped by what it is running into. More specifically, most Type Ia supernova rem-nants are very symmetrical, but the Kepler remnant is asymmetrical with a bright arc of X-ray emission in its northern region. This indicates the expanding ball of debris from the supernova explosion is plowing into the gas and dust around the now-dead star.
The bright X-ray arc can be explained in two ways. In one model, the pre-supernova star and its companion were moving through the interstellar gas and losing mass at a significant rate via a wind, creating a bow shock wave similar to that of a boat moving through water. Another possibility is that the X-ray arc is caused by debris from the supernova expanding into an interstellar cloud of gradually increasing density. The wind and bow shock model described above requires that the Kepler supernova remnant is located at a distance of more than 23,000 light years. In the latter alternative, the gas into which the remnant is expanding has higher density than average, and the distance of the remnant from the earth is between about 16,000 and 20,000 light years. Both alternatives give greater distances than the commonly used value of 13,000 light years.
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Doing Science with a Spacecraft’s
Signal By David Doody
Mariner 2 to Venus, the first interplanetary flight, was launched August 27 fifty years ago. This was a time when scientists were first learning that Venus might not harbor jungles under its thick atmosphere after all. A Russian scientist had discov-ered that atmosphere during the rare Venus transit of 1761, because of the effects of sunlight from behind.
Mariner 2 proved interplanetary flight was possible, and our ability to take close-up images of other planets would be richly rewarding in scientific return. But it also meant we could use the spacecraft itself as a “light” source, planting it behind an object of our choosing and making direct measurements.
Mariner 4 did the first occultation experiment of this sort when it passed behind Mars as seen from Earth in July 1965. But, instead of visible light from the Sun, this occultation experiment used the spacecraft’s approximately 2-GHz radio signal.
The Mariner 4 experiment revealed Mars’ thin atmosphere. Since then, successful radio science occultation experiments have been conducted at every planet and many large moons. And another one is on schedule to investigate Pluto and its companion Charon, when the New Horizons spacecraft flies by in July 2015. Also, during that flyby, a different kind of radio science occultation experiment will investigate the gravitational field.
The most recent radio science occultation experiment took place September 2, 2012, when the Cassini spacecraft carried its three transmitters behind Saturn. These three different frequencies are all kept precisely “in tune” with one another, based on a reference frequency sent from Earth. Compared to observations of the free space for calibration just before ingress to occultation, the experiment makes it possible to tease out a wide variety of components in Saturn's ionosphere
and atmosphere.
Occultation experiments comprise only one of many categories of radio science experiments. Others include tests of General Relativity, study-ing the solar corona, mapping gravity fields, determining mass, and more. They all rely on NASA’s Deep Space Network to capture the signals, which are then archived and studied.
Find out more about spacecraft science ex-periments in “Basics of Space Flight,” a website and book by this author, http://jpl.nasa.gov/basics. Kids can learn all about NASA’s Deep Space Network by playing the “Uplink-Downlink” game at http://spaceplace.nasa.gov/dsn-game.
In this poster art of Mariner 4, you can see the parabolic reflector atop the spacecraft bus. Like the reflector inside a flashlight, it sends a beam of electromagnetic energy in a particular direc-tion. Credit: NASA/JPL/Corby Waste.
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Odd Galaxy Couple on Space Voyage Two very different galaxies drift through space together in this image taken by NASA's Hubble Space Telescope. The peculiar galaxy pair is called Arp 116. Arp 116 is composed of a giant elliptical galaxy known as Messier 60 (or M60) and a much smaller spiral galaxy, NGC 4647. The faint bluish spiral gal-axy NGC 4647 is about two-thirds of M60 in size and much lower in mass — roughly the size of our gal-axy, the Milky Way.
M60 lies roughly 54 million light-years away from Earth; NGC 4647 is about 63 million light-years away. This image combines exposures from Hubble's Advanced Camera for Surveys and Wide Field and Planetary Camera 2.
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All the years attending Okie-Tex have taught me you have to be ready for anything. No matter what the weather predictions are this area has a way of surprising. Friday night was a perfect example. As the sun set the night sky was mostly clear and the temperature dropped quickly, all the way down to 37 degrees. It was time to break out the cold weather gear. Although my imaging run was over by 3:00am Saturday morning, I visually observed for hours. This was my final night and I went the distance, from sunset to the end of darkness. I was waiting to see the morn-ing Zodiacal light as I’ve done for many years. To my surprise it was not very prominent this year; the star party being a few weeks earlier than years past had a significant impact.
The essence of any star party is the opportunity to spend time under dark skies alongside others who are passion-ate about astronomy. Not every year has the best conditions, and this time the night sky above the Okie-Tex star party was average, which is actually very good by any other measure. There have been spectacular nights here, I’ve seen my shadow cast from the Milky Way and one year the Gegenschein was so bright I couldn’t believe what I was seeing. While one never knows exactly what the night will bring, you do know you’ll be surrounded by other enthusiastic amateur astronomers. I can’t wait for next year’s party! 1Reportedly Sprint service was working in the area which I find unbelievable. I was told there are plans for LTE coverage in the near future by the club’s vice president.
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NASA's WISE Survey Uncovers Millions of Black Holes NASA's Wide-field Infrared Survey Explorer (WISE) mission has led to a bonanza of newfound supermassive black holes and extreme galaxies called hot DOGs, or dust-obscured galaxies. Images from the telescope have revealed millions of dusty black hole candidates across the universe and about 1,000 even dustier objects thought to be among the brightest galaxies ever found. These powerful galaxies, which burn brightly with infrared light, are nicknamed hot DOGs.
"WISE has exposed a menagerie of hidden objects," said Hashima Hasan, WISE program scientist at NASA Headquar-ters in Washington. "We've found an asteroid dancing ahead of Earth in its orbit, the coldest star-like orbs known and now, supermassive black holes and galaxies hiding behind cloaks of dust."
WISE scanned the whole sky twice in infrared light, completing its survey in early 2011. Like night-vision goggles probing the dark, the telescope captured millions of images of the sky. All the data from the mission have been released publicly, allowing astronomers to dig in and make new discoveries.
The latest findings are helping astronomers better understand how galaxies and the behemoth black holes at their centers grow and evolve together. For example, the giant black hole at the center of our Milky Way galaxy, called Sagittarius A*, has 4 million times the mass of our sun and has gone through periodic feeding frenzies where material falls towards the black hole, heats up and irradiates its surroundings. Bigger central black holes, up to a billion times the mass of our sun,
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With its all-sky infrared survey, NASA's Wide-field Infrared Survey Explorer, or WISE, has identified millions of quasar can-didates. Quasars are supermassive black holes with masses millions to billions times greater than our sun. The black holes "feed" off surrounding gas and dust, pulling the material onto them. As the material falls in on the black hole, it be-comes extremely hot and extremely bright. This image zooms in on one small region of the WISE sky, covering an area about three times larger than the moon. The WISE quasar candidates are highlighted with yellow circles.
may even shut down star formation in galaxies. In one study, astronomers used WISE to identify about 2.5 million actively feeding supermassive black holes across the full sky, stretching back to distances more than 10 billion light-years away. About two-thirds of these objects never had been detected before because dust blocks their visible light. WISE easily sees these monsters because their powerful, accreting black holes warm the dust, causing it to glow in infrared light.
"We've got the black holes cornered," said Daniel Stern of NASA's Jet Propulsion Laboratory, Pasadena, Calif., lead author of the WISE black hole study and project scientist for another NASA black-hole mission, the Nuclear Spectro-scopic Telescope Array (NuSTAR). "WISE is finding them across the full sky, while NuSTAR is giving us an entirely new look at their high-energy X-ray light and learning what makes them tick."
In two other WISE papers, researchers report finding what are among the brightest galaxies known, one of the main goals of the mission. So far, they have identified about 1,000 candidates. These extreme objects can pour out more than 100 trillion times as much light as our sun. They are so dusty, however, that they appear only in the longest wavelengths of infrared light captured by WISE. NASA's Spitzer Space Telescope followed up on the discoveries in more detail and helped show that, in addition to hosting supermassive black holes feverishly snacking on gas and dust, these DOGs are busy churning out new stars.
"These dusty, cataclysmically forming galaxies are so rare WISE had to scan the entire sky to find them," said Peter Eisenhardt, lead author of the paper on the first of these bright, dusty galaxies, and project scientist for WISE at JPL. "We are also seeing evidence that these record setters may have formed their black holes before the bulk of their stars. The 'eggs' may have come before the 'chickens.'"
More than 100 of these objects, located about 10 billion light-years away, have been confirmed using the W.M. Keck Observatory on Mauna Kea, Hawaii, as well as the Gemini Observatory in Chile, Palomar's 200-inch Hale telescope near San Diego, and the Multiple Mirror Telescope Observatory near Tucson, Ariz. The WISE observations, com-bined with data at even longer infrared wavelengths from Caltech's Submillimeter Observatory atop Mauna Kea, re-vealed that these extreme galaxies are more than twice as hot as other infrared-bright galaxies. One theory is their dust is being heated by an extremely powerful burst of activity from the supermassive black hole.
"We may be seeing a new, rare phase in the evolution of galaxies," said Jingwen Wu of JPL, lead author of the study on the submillimeter observations. All three papers are being published in the Astrophysical Journal.
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In either model, the X-ray spectrum - that is, the amount of X-rays pro-duced at different energies reveals the presence of a large amount of iron, and indicates an explosion more energetic than the average Type Ia supernova. Additionally, to explain the observed X-ray spec-trum in this model, a small cavity must have been cleared out around the star before it exploded. Such a cavity, which would have a diameter less than a tenth that of the rem-nant's current size, might have been produced by a fast, dense outflow
from the surface of the white dwarf before it exploded, as predicted by some models of Type Ia supernovas.
Additionally, to explain the observed X-ray spectrum in this model, a small cavity must have been cleared out around the star before it exploded. Such a cavity, which would have a diameter less than a tenth that of the remnant, might have been produced by a fast, dense outflow from the surface of the white dwarf before it exploded, as predicted by some models of Type Ia supernovas.
Evidence for an unusually powerful Type Ia supernova has previously been observed in another remnant with Chandra and an optical telescope. These results were independently verified by subsequent observations of light from the original supernova explosion that bounced off gas clouds, a phenomenon called light echoes. This other remnant is located in the Large Magellanic Cloud, a small galaxy about 160,000 light years from Earth, making it much farther away than Kepler and therefore more difficult to study.
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Spitzer Finds Possible Exoplanet Smaller than Earth Astronomers using NASA's Spitzer Space Telescope have detected what they believe is a planet two-thirds the size of Earth. The exoplanet candidate, called UCF-1.01, is located a mere 33 light-years away, making it possi-bly the nearest world to our solar system that is smaller than our home planet.
Exoplanets circle stars beyond our sun. Only a handful smaller than Earth have been found so far. Spitzer has performed transit studies on known exoplanets, but UCF-1.01 is the first ever identified with the space telescope, pointing to a possible role for Spitzer in helping discover potentially habitable, terrestrial-sized worlds.
"We have found strong evidence for a very small, very hot and very near planet with the help of the Spitzer Space Telescope," said Kevin Stevenson from the University of Central Florida in Orlando. Stevenson is lead author of the paper, which has been accepted for publication in The Astrophysical Journal. "Identifying nearby small plan-ets such as UCF-1.01 may one day lead to their characterization using future instruments."
The hot, new-planet candidate was found unexpectedly in Spitzer observations. Stevenson and his colleagues were studying the Neptune-sized exoplanet GJ 436b, already known to exist around the red-dwarf star GJ 436. In
the Spitzer data, the astronomers noticed slight dips in the amount of infrared light streaming from the star, sepa-rate from the dips caused by GJ 436b. A review of Spitzer archival data showed the dips were periodic, suggest-ing a second planet might be orbiting the star and blocking out a small fraction of the star's light.
This technique, used by a number of observatories including NASA's Kepler space telescope, relies on transits to detect exoplanets. The duration of a transit and the small decrease in the amount of light registered reveals basic properties of an exoplanet, such as its size and distance from its star. In UCF-1.01's case, its diameter would be approximately 5,200 miles (8,400 kilometers), or two-thirds that of Earth. UCF-1.01 would revolve quite tightly around GJ 436, at about seven times the distance of Earth from the moon, with its "year" lasting only 1.4 Earth days. Given this proximity to its star, far closer than the planet Mercury is to our sun, the exoplanet's surface tem-perature would be more than 1,000 degrees Fahrenheit (almost 600 degrees Celsius).
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Artist’s conception of Earth-size planet with a magma dominated surface newly discovered by the Spitzer Infra-red Space Observatory.
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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 October 2012
If the roasted, diminutive planet candidate ever had an atmosphere, it almost surely has evaporated. UCF-1.01 might therefore resemble a cratered, mostly geologically dead world like Mercury. Paper co-author Joseph Harring-ton, also of the University of Central Florida and principal investigator of the research, suggested another possibil-ity; that the extreme heat of orbiting so close to GJ 436 has melted the exoplanet's surface.
"The planet could even be covered in magma," Harrington said.
In addition to UCF-1.01, Stevenson and his colleagues noticed hints of a third planet, dubbed UCF-1.02, orbiting GJ 436. Spitzer has observed evidence of the two new planets several times each. However, even the most sensi-tive instruments are unable to measure exoplanet masses as small as UCF-1.01 and UCF-1.02, which are perhaps only one-third the mass of Earth. Knowing the mass is required for confirming a discovery, so the paper authors are cautiously calling both bodies exoplanet candidates for now.
Of the approximately 1,800 stars identified by NASA' Kepler space telescope as candidates for having planetary systems, just three are verified to contain sub-Earth-sized exoplanets. Of these, only one exoplanet is thought to be smaller than the Spitzer candidates, with a radius similar to Mars, or 57 percent that of Earth.
"I hope future observations will confirm these exciting results, which show Spitzer may be able to discover exoplan-ets as small as Mars," said Michael Werner, Spitzer project scientist at NASA's Jet Propulsion Laboratory in Pasa-dena, Calif. "Even after almost nine years in space, Spitzer's observations continue to take us in new and important scientific directions..”
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