about the astronomy associates of...
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COMING EVENTS Public Observing Sunday Dec. 02
Prairie Park Nature Center 8:00 PM
Monthly Meeting
Friday DEC. 07 7:30 PM, 2001 Malott
A Public Observatory at Baker Wetlands Dr. Roger L. Boyd
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: Our speaker for the Novem-ber meeting was KU Profes-sor Emeritus Tom Armstrong. Tom gave an entertaining talk on the continued operation of the Voyager 1 spacecraft, an exceptionally successful NASA mission that continues to pro-vide data and new results into the structure of the outer solar system and its interaction with interstellar space. In addition to the science, Tom supplied some personal insight into the behind-the-scenes stories that always surround a large scientific en-deavor, the small things that surprisingly can make or break a complicated project.
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Volume 38 Number 12 December 2012
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INSIDE THIS ISSUE
Makemake (continued) 2
Solar Systems with Extra Comets
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NASA Space Place 4
DEC. Meeting Poster 5
Record X-Ray Jet 6
A Star-Forming Region 7
Most Distant Galaxy 8
Another Stellar Nursery 9
Distant Galaxy (continued) 10
Dwarf Planet Makemake Lacks Atmosphere: Distant Frigid World Reveals Its Secrets for First Time Science News Dwarf planet Makemake is about two thirds of the size of Pluto, and travels around the Sun in a distant path that lies beyond that of Pluto but closer to the Sun than Eris, the most massive known dwarf planet in the Solar Sys-tem. Previous observations of chilly Makemake have shown it to be similar to its fellow dwarf planets, leading some astronomers to expect its atmosphere, if present, to be similar to that of Pluto. However, the new study now shows that, like Eris, Makemake is not surrounded by a significant atmosphere.The team, led by Jose Luis Ortiz (Instituto de Astrofisica de Andalucia, CSIC, Spain), combined multiple observations using three telescopes at ESO's La Silla and Paranal observing sites in Chile -- the Very Large Telescope (VLT), New Technology Telescope (NTT), and TRAPPIST (TRAnsiting Planets and PlanetesImals Small Telescope) -- with data from other small telescopes in South America, to look at Makemake as it passed in front of a distant star . "As Makemake passed in front of the star and blocked it out, the star disap-peared and reappeared very abruptly, rather than fading and brightening gradually. This means that the little dwarf planet has no significant atmos-phere," says Jose Luis Ortiz. "It was thought that Makemake had a good chance of having developed an atmosphere -- that it has no sign of one at all shows just how much we have yet to learn about these mysterious bodies. Finding out about Makemake's properties for the first time is a big step for-ward in our study of the select club of icy dwarf planets." Makemake's lack of moons and its great distance from us make it difficult to study, and what little
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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
For December, we have our annual holiday celebration with a presentation by Dr. Roger Boyd. Dr. Boyd, Professor Emeritus at Baker University, is the Director of the Baker Wetlands Science Center. Dr. Boyd has proposed construction of a public observatory at the Wetlands Science Center and will be pursuing the interest and feedback of the AAL in promoting and supporting this project. If you think a permanent site for observing in the Law-rence area would be a plus, please come by and check out the project. As members of the Astronomical League, you might be interested to know that Troy and Michelle Stratton have put together a new Observing Program for the Astronomical League, looking at famous stellar asterisms. For details of this wonderful program, see the web page at http://astroleague.org/content/asterisms-observing-program. The great tradition of dark sky observing continues with the 35th Annual TEXAS STAR PARTY, May 5-12, 2013! Staying on the Ranch in housing, RV, or camping? Staying off-site in other accommodations? If you are thinking about attending, you need to enter the TSP drawing, held in late January. You should submit a Registration/Reservation Re-quest Form to ENTER THE TSP DRAWING before January 15, 2013. This will provide you the highest possible chance of being selected as one of the 500 people who will be able to attend TSP this year. Follow this link to get started! http://texasstarparty.org/get-started/ Any suggestions for improving the club or the newsletter are always welcome.
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we do know about the body is only approximate. The team's new observations add much more detail to our view of Makemake -- determining its size more accurately, putting constraints on a possible atmosphere and estimating the dwarf planet's density for the first time. They have also allowed the astronomers to measure how much of the Sun's light Makemake's surface reflects -- its albedo. Makemake's albedo, at about 0.77, is comparable to that of dirty snow, higher than that of Pluto, but lower than that of Eris. It was only possible to observe Makemake in such detail because it passed in front of a star -- an event known as a stellar occultation. These rare opportunities are allowing astronomers for the first time to find out a great deal about the sometimes tenuous and delicate atmospheres around these distant, but important, members of the Solar Sys-tem, and providing very accurate information about their other properties. Occultations are particularly uncommon in the case of Makemake, because it moves in an area of the sky with relatively few stars. Accurately predicting and detecting these rare events is extremely difficult and the successful observation by a coordinated observing team, scattered at many sites across South America, ranks as a major achievement. "Pluto, Eris and Makemake are among the larger examples of the numerous icy bodies orbiting far away from our Sun," says Jose Luis Ortiz. "Our new observations have greatly improved our knowledge of one of the biggest, Makemake -- we will be able to use this information as we explore the intriguing objects in this region of space fur-ther." Makemake is one of five dwarf planets so far recognized by the International Astronomical Union. The others are Ceres, Pluto, Haumea and Eris.
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Herschel Serves Up Solar Systems with Extra Comets
Astronomers have discovered vast comet belts surrounding two nearby planetary systems known to host only Earth-to-Neptune-mass worlds. These cometary belts could have delivered oceans to the innermost planets. The findings are based on observations from the Herschel space telescope, a European Space Agency mission with important participation from NASA.
Last year, Herschel found that the dusty belt surrounding the nearby star Fomalhaut must be maintained by colli-sions between comets. In the new Herschel study, two more nearby planetary systems -- GJ 581 and 61 Vir --have been found to host vast amounts of cometary debris. Herschel detected the signatures of cold dust at minus 200 degrees Celsius (minus 330 degrees Fahrenheit), in quantities that mean these systems must have at least 10 times more comets than in our own solar system's Kuiper Belt.
GJ 581 (or Gliese 581) is a low-mass M dwarf star, the most common type of star in the galaxy. Earlier studies have shown that it hosts at least four planets, including one that resides in the so-called habitable zone - the re-gion from the central sun where liquid surface water could exist.
Two planets are confirmed around the G-type star 61 Vir, which is just a little less massive than our sun.
The planets in both systems are known as ''super-Earths," a term that covers a range of masses between 2 and 18 times that of Earth. Interestingly, however, there is no evidence for giant Jupiter- or Saturn-mass planets in either system. The gravitational interplay between Jupiter and Saturn in our own solar system is thought to have been responsible for disrupting a once highly populated Kuiper Belt, sending a deluge of comets toward the inner planets in a cataclysmic event that lasted several million years.
"The new observations are giving us a clue: they're saying that in the solar system we have giant planets and a relatively sparse Kuiper Belt, but systems with only low-mass planets often have much denser Kuiper belts," says Mark Wyatt from the University of Cambridge, UK, lead author of the paper focusing on the debris disk around 61 Vir. "Herschel continues to reveal surprising information about the strange configuration of solar systems in the Milky Way," said Paul Goldsmith, NASA Herschel Project Scientist at NASA''s Jet Propulsion Laboratory, Pasa-dena, Calif.
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It Takes More Than Warm Porridge to Make a Goldi-
locks Zone By Diane K. Fisher
The “Goldilocks Zone” describes the region of a solar system that is just the right distance from the star to make a cozy, comfy home for a life-supporting planet. It is a region that keeps the planet warm enough to have a liquid ocean, but not so warm that the ocean boils off into space. Obviously, Earth orbits the Sun in our solar system’s “Goldilocks Zone.”
But there are other conditions besides temperature that make our part of the solar system comfortable for life. Using infra-red data from the Spitzer Space Telescope, along with theoretical models and archival observations, Rebecca Martin, a NASA Sagan Fellow from the University of Colorado in Boulder, and astronomer Mario Livio of the Space Telescope Science Institute in Baltimore, Maryland, have published a new study suggesting that our solar system and our place in it is special in at least one other way.
This fortunate “just right” condition involves Jupiter and its effect on the asteroid belt. Many other solar systems discovered in the past decade have giant gas planets in very tight orbits around their stars. Only 19 out of 520 solar systems studied have Jupi-ter-like planets in orbits beyond what is known as the “snow line”—the distance from the star at which it is cool enough for water (and ammonia and methane) to condense into ice. Scientists believe our Jupiter formed a bit farther away from the Sun than it is now. Although the giant planet has moved a little closer to the Sun, it is still beyond the snow line.
So why do we care where Jupiter hangs out? Well, the gravity of Jupiter, with its mass of 318 Earths, has a profound effect on everything in its region, including the asteroid belt. The asteroid belt is a re-gion between Mars and Jupiter where millions of mostly rocky objects (some water-bearing) orbit. They range in size from dwarf planet Ceres at more than 600 miles in diameter to grains of dust. In the early solar system, asteroids (along with comets) could have been partly responsible for delivering water to fill the ocean of a young Earth. They could have also brought organic molecules to Earth, from which life eventually evolved. Jupiter’s gravity keeps the asteroids pretty much in their place in the asteroid
belt, and doesn’t let them accrete to form another planet. If Jupiter had moved inward through the asteroid belt toward the Sun, it would have scattered the asteroids in all directions before Earth had time to form. And no asteroid belt means no impacts on Earth, no water delivery, and maybe no life-starting molecules either. Asteroids may have also delivered such useful metals as gold, platinum, and iron to Earth’s crust.
But, if Jupiter had not migrated inward at all since it formed father away from the Sun, the asteroid belt would be totally undisturbed and would be a lot more dense with asteroids than it is now. In that case, Earth would have been blasted with a lot more asteroid impacts, and life may have never had a chance to take root.
The infrared data from the Spitzer Space Telescope contributes in unexpected ways in revealing and supporting new ideas and theories about our universe. Read more about this study and other Spitzer contributions at spitzer.caltech.edu. Kids can learn about infrared light and enjoy solving Spitzer image puzzles at spaceplace.nasa.gov/spitzer-slyder.
This article was provided by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.
Our solar system is represented by the middle scenario, where the gas giant planet has migrated inward, but still remains beyond the asteroid belt.
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GB 1428+4217: Record-Setting X-ray Jet Discovered
This composite image shows the most distant X-ray jet ever observed. X-ray data from NASA's Chandra X-ray Observatory are shown in blue, radio data from the NSF's Very Large Array are shown in purple and optical data from NASA's Hubble Space Telescope are shown in yellow. The jet was produced by a quasar named GB 1428+4217, or GB 1428 for short, and is located 12.4 billion light years from Earth. The shape of the jet is very similar in the X-ray and radio data.
Giant black holes at the centers of galaxies can pull in matter at a rapid rate producing the quasar phenome-non. The energy released as particles fall toward the black hole generates intense radiation and powerful beams of high-energy particles that blast away from the black hole at nearly the speed of light. These parti-cle beams can interact with magnetic fields or ambient photons to produce jets of radiation.
As the electrons in the jet fly away from the quasar, they move through a sea of background photons left behind after the Big Bang. When a fast-moving electron collides with one of these so-called cosmic micro-wave background photons, it can boost the photon's energy into the X-ray band. Because the quasar is seen when the universe is at an age of about 1.3 billion years, less than 10% of its current value, the cosmic background radiation is a thousand times more intense than it is now. This makes the jet much brighter, and compensates in part for the dimming due to distance.
While there is another possible source of X-rays for the jet - radiation from electrons spiraling around mag-netic field lines in the jet - the authors favor the idea that the cosmic background radiation is being boosted because the jet is so bright.
The researchers think the length of the jet in GB 1428 is at least 230,000 light years, or about twice the di-ameter of the entire Milky Way galaxy. This jet is only seen on one side of the quasar in the Chandra and VLA data. When combined with previously obtained evidence, this suggests the jet is pointed almost directly toward us. This configuration would boost the X-ray and radio signals for the observed jet and diminish those for a jet presumably pointed in the opposite direction.
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Life and Death in a Star-Forming Cloud The aftershock of a stellar explosion rippling through space is captured in this new view of the supernova remnant called W44. The image combines longer-wavelength infrared and X-ray light captured by the European Space Agency's Herschel and XMM-Newton space observatories.
W44 is located about 10,000 light-years away, within a forest of dense star-forming clouds in the constellation of Aquila, the Eagle. It is one of the best examples of a supernova remnant interacting with its parent cloud.
The supernova remnant is the result of a massive star that reached the end of its life and expelled its outer layers in a dramatic explosion. All that remains of the stellar behemoth is the spinning core of a neutron star, or pulsar.
Identified as PSR B1853+01, the pulsar is the bright point to the top left in W44, colored light blue in this image. It is thought to be around 20,000 years old. Like all pulsars, as it rapidly rotates, it sweeps out a wind of highly energetic parti-cles and beams of light ranging from radio to X-ray energies. The center of the supernova remnant is also bright in X-rays, coming from the hot gas that fills the shell at temperatures of several million degrees.
Herschel's infrared eyes seek out regions of gently heated gas and dust farther from W44, where new stars are congre-gating. Examples include the arrowhead-shaped star-formation region to the right of W44, which appears to point to an-other trio of intricate clouds further to the right and above.
More broadly, a number of compact objects scattered across the scene map the cold seeds of future stars that will eventu-ally emerge from their dusty cocoons.
Finally, diffuse purple emission towards the bottom left of the image provides a glimpse of the plane of our Milky Way gal-axy.
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NASA Great Observatories Find Candidate for Most Distant Galaxy Yet Known
By combining the power of NASA's Hubble Space Telescope, Spitzer Space Telescope, and one of nature's own natural "zoom lenses" in space, astronomers have set a new distance record for finding the farthest galaxy yet seen in the uni-verse. The diminutive blob, which is only a tiny fraction of the size of our Milky Way galaxy, offers a peek back into a time when the universe was 3 percent of its present age of 13.7 billion years. The newly discovered galaxy, named MACS0647-JD, is observed 420 million years after the big bang. Its light has traveled 13.3 billion years to reach Earth. This is the latest discovery from a large program that uses natural zoom lenses to reveal distant galaxies in the early universe. The Cluster Lensing And Supernova survey with Hubble (CLASH) is using massive galaxy clusters as cosmic telescopes to magnify distant galaxies behind them, an effect called gravitational lensing.
Along the way, 8 billion years into its journey, this light took a detour along multiple paths around the massive galaxy cluster MACS J0647+7015. Due to the gravitational lensing, the CLASH research team, an international group led by Marc Postman of the Space Telescope Science Institute in Baltimore, Md., observed three magnified images of MACS0647-JD with the Hubble telescope. The cluster's gravity boosted the light from the faraway galaxy, making the images appear approximately eight, seven, and two times brighter than they otherwise would, enabling astronomers to detect them more efficiently and with greater confidence. Without the cluster's magnification powers, astronomers would not have seen this remote galaxy. "This cluster does what no manmade telescope can do," said Postman. "Without the magnification, it would require a Herculean effort to observe this galaxy."
The object is so small it may be in the first embryonic steps of forming an entire galaxy. An analysis shows that the gal-axy is less than 600 light-years wide. Based on observations of somewhat closer galaxies, astronomers estimate that a typical galaxy of that epoch should be about 2,000 light-years wide. For comparison, the Large Magellanic Cloud, a com-panion dwarf galaxy to the Milky Way, is 14,000 light-years wide. Our Milky Way is 150,000 light-years across.
"This object may be one of many building blocks of a galaxy," explained Dan Coe of the Space Telescope Science Insti-tute, lead author of the study. "Over the next 13 billion years, it may have dozens, hundreds, or even thousands of merg-ing events with other galaxies and galaxy fragments." The estimated total mass of the stars in this baby galaxy is roughly equal to 100 million or a billion suns, or about 0.1 percent to 1 percent the mass of our Milky Way's stars. The galaxy was observed with 17 filters — spanning near-ultraviolet to near-infrared wavelengths — using Hubble's Wide Field Camera 3 (WFC3) and Advanced Camera for Surveys (ACS). Coe, a CLASH team member, discovered the galaxy in February 2012 while pouring through a catalogue of thousands of "lensed" objects found in Hubble observations of 17 clusters in the CLASH survey. MACS0647-JD, unlike all the others, only appeared in the two reddest filters.
"This immediately told us that MACS0647-JD is either a very red object, only shining at red wavelengths, or it is extremely distant and its light has been 'redshifted' to these wavelengths, or some combination of the two," said Coe. "We considered this full range of possibilities. Coe and his collabora-tors spent months systematically ruling out these other alternative explanations for the object's identity, including red stars, brown dwarfs, and red (old and/or dusty) galaxies at intermediate distances from Earth, and concluded that a very distant galaxy was the right explanation.
"All three of the lensed galaxy images match fairly well and are in positions you would expect for a galaxy at that remote distance when you look at the predictions from our best lens models for this cluster," Coe said. Redshift is a consequence of the expansion of space over cosmic time. Coe estimates that MACS0647-JD has a redshift of 11, the highest yet observed. The wavelengths of near-ultraviolet light from the galaxy have been stretched into the near-infrared part of the spectrum as the light traveled through an expanding universe. "At early times, gal-axies are ablaze with hot, young blue stars,
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Probing a Nearby Stellar Cradle Chandra Press Release
The Milky Way and other galaxies in the universe harbor many young star clusters and associations that each contain hundreds to thousands of hot, massive, young stars known as O and B stars. The star cluster Cygnus OB2 contains more than 60 O-type stars and about a thousand B-type stars. Deep observations with NASA’s Chandra X-ray Observatory have been used to detect the X-ray emission from the hot outer atmospheres, or coronas, of young stars in the cluster and to probe how these fascinating star factories form and evolve. About 1,700 X-ray sources were detected, including about 1,450 thought to be stars in the cluster. In this image, X-rays from Chandra (blue) have been combined with infrared data from NASA’s Spitzer Space Telescope (red) and optical data from the Isaac Newton Telescope (orange). Young stars ranging in age from one million to seven million years were found. The infrared data indicates that a very low fraction of the stars have circumstellar disks of dust and gas. Even fewer disks were found close to the massive OB stars, betraying the corrosive power of their intense radiation that leads to early destruction of their disks. There is also evidence that the older popula-tion of stars has lost its most massive members because of supernova explosions. Finally, a total mass of about 30,000 times the mass of the sun is derived for Cygnus OB2, similar to that of the most massive star forming re-gions in our Galaxy. This means that Cygnus OB2, located only about 5,000 light years from Earth, is the closest massive star cluster. This composite image of the star cluster Cygnus OB2 contains X-rays from Chandra (blue), infrared data from Spitzer (red), and optical emission from the Isaac Newton Telescope (orange).
AAL Astronomy Associates of Lawrence
University of Kansas Malott Hall 1251 Wescoe Hall Dr, Room 1082 Lawrence, KS 66045-7582
Celestial Mechanic December 2012
but they appear extremely red when we see their light with Hubble."
Images of the galaxy at longer wavelengths obtained with the Spitzer Space Telescope played a key role in the analy-sis. If the object were intrinsically red, it would appear bright in the Spitzer images. Instead, the galaxy was barely de-tected, if at all, indicating its great distance. The research team plans to use Spitzer to obtain deeper observations of the galaxy, which should yield confident detections as well as estimates of the object's age and dust content. The first galaxies probably formed somewhere between 100 million and 500 million years after the big bang, the astronomers said. Galaxies formed at earlier times are found to be more pristine, relatively free from heavy-element enrichment by later generations of supernovae.
The small-fry galaxy, however, may be too far away for any current telescope to confirm the distance based on spec-troscopy, which spreads out an object's light into thousands of colors. Nevertheless, Coe is confident the fledgling gal-axy is the new distance champion based on its unique colors and the research team's extensive analysis. By measur-ing how bright the object is at various wavelengths, the team determined a reasonably accurate estimate of the object's distance. Near-infrared wavelengths are the most critical to making distance estimates for such far-off objects. The galaxy will almost certainly be a prime target for the James Webb Space Telescope. "We are reaching the limit of Hub-ble's vision because the galaxy is barely resolved," Postman said. "To really see finer structure you need a bigger tele-scope." At near-infrared wavelengths, Webb's resolution will be three times sharper than Hubble's. The Webb tele-scope's larger mirror will also collect enough light to obtain a spectrum of MACS0647-JD. This will yield a more defini-tive and precise measurement of the galaxy's distance, as well as the galaxy's mass, age, and amount of heavy ele-ments it contains, which were forged by the first generation of stars.
The new distance champion is the second remote galaxy uncovered in the CLASH survey, a multi-wavelength census of 25 hefty galaxy clusters with Hubble's ACS and WFC3. Earlier this year, the CLASH team announced the discovery of a galaxy that existed when the universe was 490 million years old (redshift 9.6), 70 million years later than the new record-breaking galaxy. So far, the survey has completed observations for 20 of the 25 clusters.
The team hopes to use Hubble to search for more dwarf galaxies at these early epochs. If these infant galaxies are numerous, then they could have provided the energy to burn off the fog of hydrogen that blanketed the universe, a process called reionization. Reionization ultimately made the universe transparent to light.
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