June 15, 2006, 11:59 PM CT

Three New Asteroids Sharing Neptune's Orbit

Three new objects locked into roughly the same orbit as Neptune--called "Trojan" asteroids--have been found by scientists from the Carnegie Institution's Department of Terrestrial Magnetism (DTM) and the Gemini Observatory in Hilo, Hawaii. The discovery offers evidence that Neptune, much like its big cousin Jupiter, hosts thick clouds of Trojans in its orbit, and that these asteroids probably share a common source. It also brings the total of known Neptune Trojans to four.

"It is exciting to have quadrupled the known population of Neptune Trojans," said Carnegie Hubble Fellow Scott Sheppard, lead author of the study, which appears in the June 15 online issue of Science Express. "In the process, we have learned a lot both about how these asteroids become locked into their stable orbits, as well as what they might be made of, which makes the discovery particularly rewarding."

The recently discovered Neptune Trojans are only the fourth stable group of asteroids observed around the Sun. The others are the Kuiper Belt just beyond Neptune, the Jupiter Trojans, and the main asteroid belt between Mars and Jupiter. Evidence suggests that the Neptune Trojans are more numerous than either the main asteroid belt or the Jupiter Trojans, but they are hard to observe because they are so far away from the Sun. Astronomers therefore require the largest telescopes in the world equipped with sensitive digital cameras to detect them.........

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June 11, 2006, 12:45 AM CT

FUSEing Carbon Planets

Scientists using NASA's Far Ultraviolet Spectroscopic Explorer, or FUSE, have discovered abundant amounts of carbon gas in a dusty disk surrounding a well-studied young star named Beta Pictoris.

Asteroids and comets orbiting Beta Pictoris might contain large amounts of carbon-rich material, such as graphite and methane. Planets forming from or impacted by such bodies would be very different from those in our solar system and might have methane-rich atmospheres, like Titan, a moon of Saturn.

"We have learned in the past ten years is that our galaxy is filled with other solar systems, and each one is different from the next," said Dr. Marc Kuchner of NASA Goddard, an expert on extra-solar planets. "If carbon-rich worlds are forming in Beta Pictoris, they might be covered with tar and smog, with mountains made of giant diamonds. Life on such a planet is not implausible, but it certainly would be exotic".

second possibility is that Beta Pictoris might be similar to our solar system long ago. While local asteroids and comets don't seem carbon-rich today, some research suggests that certain meteorites called enstatite chondrite meteorites formed in a carbon-rich environment, and some scientists speculate that Jupiter has a carbon core.

"We might be observing processes that occurred early in our solar system's development," said Nature co-author Dr. Alycia Weinberger of the Carnegie Institution of Washington.........

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June 8, 2006, 0:04 AM CT

Mysterious Carbon Excess Found In Infant Solar System

D.C. Astronomers detected uncommonly high quantities of carbon, the basis of all terrestrial life, in an infant solar system around nearby star Beta Pictoris, 63 light-years away. "For years we've looked to this early forming solar system as one that might be going through the same processes our own solar system did when the rocky planets, including Earth, were forming," commented lead author Aki Roberge,* who began the research while at Carnegie's Department of Terrestrial Magnetism. "But we got a big surprise--there is much more carbon gas than we expected. Something very different is going on." The research, reported in the June 8, 2006, Nature, suggests that either carbon-rich asteroids or comets, unlike any in our own solar system, have vaporized, or that bodies outgassing carbon-bearing species such as methane contribute the curious carbon excess.

Dusty, gaseous disks around stars are the birthplaces of planetary systems. Carnegie researcher Alycia Weinberger, co-author of the study, explains: "Since we can't observe our own solar system as it was 4.5 billion years ago, we look at young stars to learn about the evolution of planet-forming disks. Ultimately, we want to understand the environments and processes around other stars that lead to the rise of life."

The new research was made possible by FUSE--NASA's Far Ultraviolet Spectroscopic Explorer--and data from the Hubble Space Telescope's imaging spectrograph. Beta Pictoris is almost twice the mass of our Sun and between 8 and 20 million years old. Prior studies indicated that the gas around the star had a composition of elements very similar to that in our own solar system. The new measurements mark the "most complete inventory of gas in any debris disk," and may radically change the picture.........

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June 5, 2006, 9:35 PM CT

Images Contrast Evolution Of Stars

Two new images from the Gemini Observatory released recently (Monday June 5th 2006) at the American Astronomical Society meeting in Calgary, Canada, show a pair of beautiful nebulae that were created by two very different types of stars at what may be similar points in their evolutionary timelines.

One is a rare type of very massive spectral-type "O" star surrounded by material it ejected in an explosive event earlier in its life that continues to lose mass in a steady "stellar wind." The other is a star originally more similar to our Sun that has lost its outer envelope following a "red giant" phase. It continues to lose mass via a stellar wind as it dies, forming a planetary nebula. The images were made using the Gemini Multi-Object Spectrograph (GMOS) on Gemini South as part of the Gemini Legacy Imaging program.

GMOS was built as a joint UK / Canadian effort by the UK Astronomy Technology Centre (UKATC) in Edinburgh, the University of Durham and the Dominion Astrophysical Observatory in Canada. Its creators praise the performance of GMOS. Professor James Dunlop of the University of Edinburgh, current Chair of Gemini Science Committee, said "The Gemini telescope using GMOS is unrivalled in its ability to take stunning images of distant phenomena in our Galaxy and beyond".........

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June 5, 2006, 9:09 PM CT

Galaxy Evolution In Cyber Universe

Scientists at the University of Chicago have bolstered the case for a popular scenario of the big bang theory that neatly explains the arrangement of galaxies throughout the universe. Their supercomputer simulation shows how dark matter, an invisible material of unknown composition, herded luminous matter in the universe from its initial smooth state into the cosmic web of galaxies and galaxy clusters that populate the universe.

Previous studies by other researchers had already verified the main features of this scenario, called the cold dark matter model. The Chicago team further extended this work by comparing the results of their supercomputer simulations to the newest, most detailed astronomical observations available today. They found an excellent fit, and they did so without basing their simulations on a lot of complex assumptions.

"The model we use is really, really simple," said Andrey Kravtsov, Associate Professor in Astronomy & Astrophysics. "We want to see how well this framework can do with a minimum number of assumptions".

A paper co-authored by Kravtsov, Charlie Conroy and Risa Wechsler describing these findings would be published in the June 20 issue of the Astrophysical Journal. The research was funded by a grant from the National Science Foundation, with additional support from the National Aeronautics and Space Administration.........

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June 5, 2006, 8:58 PM CT

Planemos May Spawn Planets And Moons

Forget our traditional ideas of where a planetary system forms - new research led by a University of Toronto astronomer reveals that planetary nurseries can exist not only around stars but also around objects that are themselves not much heftier than Jupiter. It suggests that miniature versions of the solar system may circle objects that are some 100 times less massive than our sun.

That's the dramatic conclusion of two studies being presented today at the American Astronomical Society meeting in Calgary by Professor Ray Jayawardhana and colleagues. The new findings show that objects only a few times more massive than Jupiter are born with disks of dust and gas, the raw material for planet making. Research done by Jayawardhana's group and others in recent years had shown that disks are common around failed stars known as "brown dwarfs". Now, they report, the same appears to be true for their even punier cousins, sometimes called planetary mass objects or "planemos." These objects, discovered within the past five years, have masses similar to those of extra-solar planets, but they are not in orbit around stars - instead, they float freely through space.

"Now that we know of these planetary mass objects with their own little infant planetary systems, the definition of the word 'planet' has blurred even more," says Jayawardhana, an associate professor of astronomy and astrophysics. "In a way, the new discoveries are not too surprising - after all, Jupiter must have been born with its own disk, out of which its bigger moons formed".........

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June 4, 2006, 1:43 PM CT

The Lovell Telescope

I've just been looking though some of my photos from a few years ago so thought I would share one.

This is a photo of the University of Manchester's Lovell Telescope. It's a radio telescope and is 76m across (equivalent to about three public swimming pool lengths). It was the largest radio telescope in the world when it was built in 1957. It had cost rather a lot of public money and was in financial difficulties before it was even finished. Eventhough it was a University built science project, it turned out to be the only facility in the world that could track the carrier rockets that launched the Soviet Union's Sputnik satellite. Involving Britain with the start of the space race helped to save both it and the observatory and it's still going strong today. Look out for lots of 50th anniversary events happening next year.........

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June 4, 2006, 1:10 PM CT

New Views Of Near-Earth Object

A Japanese spacecraft has delivered an unprecedented look at one of the near-Earth asteroids that frequently fly by our planet.

Hayabusa, Japanese for "falcon," achieved a close encounter with asteroid 25143 Itokawa last November.

At 1,640 feet (500 meters) long, the asteroid is a small, rocky, "S-type" usually found in the inner regions of the main asteroid belt (virtual solar system).

To some observers Itokawa resembles a lumpy potato. Others see a celestial sea otter with a small "head" and larger "body" (sea otter photo and profile).

Hayabusa hovered over the oddly shaped asteroid taking images and readings before achieving a daring touchdown in an attempt to capture the first ever asteroid-surface samples.

Technical problems intervened, and it's unclear whether Hayabusa was able to secure a sample or whether engineers will be able to guide the spacecraft back to Earth some 180 million miles (290 million kilometers) away.

Despite these setbacks, the scientists say the spacecraft's rendezvous and landing were striking successes.

The mission sent back detailed images of Itokawa's surface, some from such a close vantage point that they include the spacecraft's shadow.

Hayabusa also made important measurements of the asteroid's mass and composition.........

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June 1, 2006, 7:36 PM CT

Close-up On Zucchius Crater

This image, taken by the advanced Moon Imaging Experiment (AMIE) on board ESA's SMART-1 spacecraft, shows the central peaks of crater Zucchius.

AMIE obtained this image on 14 January 2006 from a distance of about 753 kilometres from the surface, with a ground resolution of 68 metres per pixel.

The imaged area is centred at a latitude of 61.3º South and longitude 50.8º West. Zucchius is a prominent lunar impact crater located near the southwest limb. It has 66 kilometres diameter, but only its inside is visible in this image, as the AMIE field of view is 35 kilometres from this close-up distance.

Because of its location, the crater appears oblong-shaped due to foreshortening. It lies just to the south-southwest of Segner crater, and northeast of the much larger Bailly walled-plain. To the southeast is the Bettinus crater, a formation only slightly larger than Zucchius.

Zucchius formed in the Copernican era, a period in the lunar planetary history that goes from 1.2 thousand million years ago to present times. Another example of craters from this period are Copernicus (about 800 milion years old) and Tycho (100 million years old). Craters from the Copernican era show characteristic ejecta ray patterns - as craters age, ejecta rays darken due to weathering by the flowing solar wind.........

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June 1, 2006, 7:23 PM CT

The Case of the Neutron Star

A long observation with NASA's Chandra X-ray Observatory revealed important new details of a neutron star that is spewing out a wake of high-energy particles as it races through space. The deduced location of the neutron star on the edge of a supernova remnant, and the peculiar orientation of the neutron star wake, pose mysteries that remain unresolved.

"Like a kite flying in the wind, the behavior of this neutron star and its wake tell us what sort of gas it must be plowing through," said Bryan Gaensler of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., and lead author of a paper submitted to The Astrophysical Journal. "Yet we're not yet sure how the neutron star got to its present location."

The neutron star, known as CXOU J061705.3+222127, or J0617 for short, appears to lie near the outer edge of an expanding bubble of hot gas associated with the supernova remnant IC 443. Presumably, J0617 was created at the time of the supernova -- approximately 30,000 years ago -- and propelled away from the site of the explosion at about 500,000 miles per hour.

However, the neutron star's wake is oriented almost perpendicularly to the direction expected if the neutron star were moving away from the center of the supernova remnant. This apparent misalignment had previously raised doubts about the association of the speeding neutron star with the supernova remnant.........

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