Archive for August 6, 2013

Explosion Illuminates Invisible Galaxy In The Dark Ages

Artist's illustration. Credit: Gemini Observatory/AURA, artwork by Lynette Cook

Artist’s illustration. Credit: Gemini Observatory/AURA, artwork by Lynette Cook

More than 12 billion years ago a star exploded, ripping itself apart and blasting its remains outward in twin jets at nearly the speed of light. At its death it glowed so brightly that it outshone its entire galaxy by a million times. This brilliant flash traveled across space for 12.7 billion years to a planet that hadn’t even existed at the time of the explosion – our Earth. By analyzing this light, astronomers learned about a galaxy that was otherwise too small, faint and far away for even the Hubble Space Telescope to see.

“This star lived at a very interesting time, the so-called dark ages just a billion years after the Big Bang,” says lead author Ryan Chornock of the Harvard-Smithsonian Center for Astrophysics (CfA). “In a sense, we’re forensic scientists investigating the death of a star and the life of a galaxy in the earliest phases of cosmic time,” he adds.

The star announced its death with a flash of gamma rays, an event known as a gamma-ray burst (GRB). GRB 130606A was classified as a long GRB since the burst lasted for more than four minutes. It was detected by NASA’s Swift spacecraft on June 6th. Chornock and his team quickly organized follow-up observations by the MMT Telescope in Arizona and the Gemini North telescope in Hawaii.

“We were able to get right on target in a matter of hours,” Chornock says. “That speed was crucial in detecting and studying the afterglow.”

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Subaru Telescope’s Imaging Discovery Of A Second Jupiter Shows The Power And Significance Of The SEEDS Project

Astronomers in the Strategic Explorations of Exoplanets and Disks with Subaru (SEEDS) Project have recently discovered and captured an image of the least massive planet ever imaged so far–a so-called “second Jupiter”. This discovery marks an important step toward the direct imaging of much fainter Earth-like planets in the future and may lead to new models of planet formation. It also illustrates the important role that the SEEDS project plays in observational astronomy.

Exoplanets are planets orbiting stars other than our Sun, outside of our Solar System. As of July 2013, most of the 890 exoplanets reported thus far have been discovered by indirect observation techniques, e.g. monitoring the host star for radial velocity variation or planetary transits (Note 1). Such techniques require observations over at least one orbital period and are impractical for detecting planets that are widely separated from their host stars and have long orbital periods. In contrast, direct imaging may be the most important way to observe exoplanets, because it yields information about the planet’s luminosity, temperature, atmosphere, and orbit.

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Excellent Prospects For August’s Perseid Meteors

The Perseid meteor shower, an annual celestial event beloved by millions of skywatchers around the world, returns to the night sky this week. And because the Moon will be just past new, no moonlight will hinder the view.

Sky & Telescope magazine predicts that the Perseid shower will be at or near its peak late on Sunday night (late on August 11th and early morning on the 12th) and on Monday night (August 12-13). “The nearly moonless sky this year means the viewing will be excellent,” notes Alan MacRobert, a senior editor at Sky & Telescope.

Although an occasional Perseid meteor might catch your attention shortly after evening twilight ends, the prime viewing hours are from about 11 p.m. or midnight (local time) until the first light of dawn. This is when the shower’s “radiant,” its perspective point of origin, is high up in your sky. The higher the radiant, the more meteors appear all over the sky.

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