Thursday, April 26, 2012

Astronomers identify three extrasolar planets

The team of astronomers used the Cornell-built Near-Infrared Triple Spectrograph (TripleSpec) at California’s Mount Palomar Observatory to measure the temperatures and metallicities of small stars called M dwarfs, first recorded by the NASA Kepler mission, which then led to observations of planets orbiting these stars. Kepler launched in 2009 to search for planets outside our solar system, which are called extrasolar planets or exoplanets. The team that built TripleSpec, completed in 2008, was led by Terry Herter, Cornell professor of astronomy.

The findings were published online April 23 in Astrophysical Journal Letters (Vol. 750, No. 2). The discovery could lead to better studies of these planets and pave the way toward discovering planets just like Earth.

The three planets orbit within their host stars’ “habitable zones” — the orbital distance in which liquid water could exist, and the sweet spot for determining whether life could be possible. The host stars — KOI (Kepler Object of Interest) 463.01, KOI 812.03 and KOI 854.01 — are located in areas of the sky between the constellations Cygnus and Lyra, in the range of a few hundred to a few thousand light years away.

“There is a fairly solid argument that the vast majority of planets in the universe, and quite possibly the Earthlike habitable zone planets, are planets orbiting M dwarfs,” said Jamie Lloyd, associate professor of astronomy and mechanical and aerospace engineering, and paper co-author.

The Kepler mission continuously monitors 150,000 stars for transit signals — a dip in the star’s brightness due to the passing of a planet. The Cornell team narrowed the list to 80 stars with these signals, focusing on stars called M dwarfs. These are smaller, dimmer stars than our sun, but the majority of the stars in the universe are M dwarfs, the researchers said.

Full article: … rasolar-planets.html

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