December 2, 2011
Astronomers Find New Planet 352 Light-Years Away
A team of more than 65 astronomers, including those working at the National Optical Astronomy Observatory (NOAO) and NASA, discovered a new planet nearly the size of Earth, NOAO announced on Wednesday.
The planet, Kepler-21b, was found circling a star about 352 light years away. “By astronomical standards, that´s right next door,” Katy Garmany, the Deputy Press Officer at the NOAO, told Huffington Post.The research team, led by Steve Howell of NASA Ames Research Center, has shown that Kepler-21b is about 1.6 times that of Earth´s radius and has a mass about 10 times greater. The planet orbit´s an extremely bright star at about 3.75 million miles away. It circles its star about once every 2.8 days.
With such a short period, and such a bright star, the team needed multiple telescopes on the ground to support and confirm the planet´s existence. These included the 4 meter Mayall telescope and the WIYN telescope at Kitt Peak National Observatory.
When comparing Kepler-21b to our Sun´s closest planet, Mercury, a pretty grim picture is painted. Mercury is more than 35 million miles away from the Sun. So, based on that evidence, Kepler-21b would be far hotter than Mercury, and could never sustain life as we know it.
The team calculated that the temperature on the surface of Kepler-21b is about 2,960 degrees Fahrenheit, nowhere near the habitable zone in which liquid water might be found.
Astronomers frequently discover new planets -- more than 2,000, according to Time Magazine -- but Garmany said what is exciting about Kepler-21b is that it is relatively the same size as Earth.
“Until a few years ago, the smallest extra-solar planet that we had discovered was the size of Jupiter or Saturn, which are about ten times bigger than the Earth,” Garmany told the American news website. “Now we´re getting down to something almost the size of the Earth, showing that we have the technology to find the earth-size planets.”
Kepler´s host star, HD 179070, is just a bit bigger and hotter than our Sun, although it is much younger. Its mass is 1.3 solar masses, it has a radius of 1.9 solar radii, and based on stellar models, its age is 2.84 billion years old -- our Sun is 4.6 billion years old. While HD 179070 is relatively close to us in astronomical standards, it cannot be viewed by the naked eye. However, a small telescope could easily pick it out.
Phil Plait, the Bad Astronomer, wrote in Discover Magazine that researchers carried out their studies and examinations of Kepler-21b for 15 months before making their findings public.
The results of their study will be published in Astrophysical Journal, a peer-reviewed journal covering astronomy and astrophysics.
Image Caption: The Kepler field as seen in the sky over Kitt Peak National Observatory. The approximate position of HD 179070 is indicated by the circle (sky imaged using a diffraction grating to show spectra of brighter stars, credit J. Glaspey; telescopes imaged separately and combined, credit P. Marenfeld)
On the Net: