The Hubble Space Telescope has helped astronomers uncover an object right at the dividing line between stars and planets. The object, known as CHXR 73 B, weighs in at about 12 times the mass of Jupiter, and orbits a larger red dwarf star. The two objects are separated by 200 times the distance of the Earth to the Sun, so astronomers don’t think they both formed out of the same disk of gas and dust.
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Astrophoto: Stellar Nursery NGC 7129 by Bob Allevo
Prior to 1957, virtually all photographs of the sky were produced as monochrome, black and white images. In that year, Ansco, once the world’s largest supplier of professional films, papers, and photo chemicals, introduced Super Anscochrome and over the next twenty-four months, full color images of the heavens were being released by the larger observatories. Over the years technology has improved and the colors captured in astronomical imagery have become more vivid and meaningful. For example, the hues seen in the accompanying picture represent not only this scene’s true-to-nature pallet, but it also reveals what you are looking at, too.
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Hubble Finds an Exoplanet’s Parent Star
When a star flared briefly, astronomers knew it was because a dimmer star had passed directly in front, acting as a lens with its gravity to focus light. Unfortunately, they couldn’t find the star. This was important, because the brief microlensing event also turned up the fact that this lensing star has a planet. Astronomers have used the power of the Hubble Space Telescope to find this dim star two years after the lensing event. Identifying the star is critical, because it allows astronomers to measure its unique characteristics, such as mass, temperature and composition.
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Twin Planemos Discovered
Astronomers have turned up plenty of extrasolar planets, but a newly discovered binary pair of planets is quite the find. The system consists of a 7-Jupiter mass planet and a 14-Jupiter mass planet… but no star. These planets – or “planemos” – just orbit each other. Their discovery challenges the current theory that planets are thought to form out of the disks of gas and dust that surround newborn stars.
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Earth-Sized Planets Could Be Nearby
Nearly all of the extrasolar planets discovered so far have been huge, Jupiter-sized and above. The question is: could smaller, Earth-sized planets last in the same star systems? Researchers created a simulation where tiny planets were put into the same system as larger planets to see if they could gather enough material to become as large as the Earth. They found that one nearby system – 55 Cancri – could have formed terrestrial planets, with substantial water in the habitable zone.
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Squadrons of Planet Hunters Could Find Life
The Hubble Space Telescope demonstrated that the best viewing is outside the Earth’s atmosphere. Over the years, a series of new telescopes have been lofted into space, and expanded this view into other wavelengths: Spitzer, Chandra, Compton, etc. Next up is the James Webb Space Telescope, with a mirror 6 times larger than Hubble, due for launch in 2013. But these observatories will pale in comparison when squadrons of space telescopes reach orbit. Both NASA and ESA are working on next generation space-based interferometers. They could answer one of the most fundamental questions of science: is there other life in the Universe?
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Protoplanetary Disk Warped by a Hidden Companion
New images of a relatively nearby protoplanetary disk, taken by the Subaru telescope on Mauna Kea, show strange banana-shaped arcs surrounding the central core. The most likely explanation for these arcs is that there’s another object orbiting the star; either a companion star or a large planet, and the gravitational interaction of this companion is distorting the disk of material. The protoplanetary disk, known as HT142527, is located 650 light-years away from Earth.
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Rotating Disk Could Contain Newly Forming Planets
Astronomers from the University of St. Andrews have found evidence that a ring of dust around nearby Epsilon Eridani is rotating. The observations were made using the Submillimetre Common User Bolometer Array (SCUBA), which images the sky in the near infrared spectrum. This gives evidence to the theory that the disks of gas we see around newborn stars will eventually go on to become planets. In fact, the clumps of material tracked by the astronomers could even be newly forming planets themselves, still embedded in a vast disk of gas and dust.
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How Super Earths Might Form
Although our Solar System only contains a “regular Earth”, astronomers predict that other systems could contain “super Earths”; rocky planets with several times the mass of our planet. A new theory predicts that these planets should be most commonly found orbiting red dwarf stars. As red dwarf stars have less mass, they’re unable to hang onto the lighter gas that go onto form gas giants. The remaining heavier elements have time to form very massive terrestrial planets.
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Large Amounts of Carbon Around a Distant Star
Astronomers have discovered a solar system with an unusually high amount of carbon; it could be at the stage where the rocky planets are forming. The system, called Beta Pictoris, is located 63 light-years from Earth and has a central star with twice the mass of our Sun. NASA’s FUSE (Far Ultraviolet Spectroscopic Explorer) and Hubble observed that gas around the star matches the composition of our own Solar System quite well. The stars intense radiation should be driving this gas away, but ionized carbon atoms are acting as a brake to keep it contained.
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