mardi 16 octobre 2012

Planet hunters found an exoplanet accompanied by four suns












Exoplanet - Exobiology.

October 16, 2012

 Artistic rendering system 4 star KIC 4862625

A voluntary group of astronomers, using a website devoted to scientific astronomy, discovered an extrasolar planet orbiting four stars. This finding was subsequently confirmed by a second team of researchers.

Barely a year ago, astronomers were not sure that planets could exist in a binary system of stars, where two stars orbit each other. But after the discovery of circumbinary exoplanet, which would be two suns in the sky (much like the famous Star Wars Tatooine) scientists have realized that these worlds are possible and found at least five other similar systems.

About half of the stars in the universe are being a couple and if they can host planets then the chances of a life outside of our own world could be significantly increased.

The new exoplanet orbiting within a 4 star, named KIC 4862625, approximately 3200 light years from Earth. Scientists "citizens" Jek Kian San Francisco and Robert Gagliano Cottonwood, Arizona, have used the site Planethunters.org to analyze the data of these stars captured by the Kepler space telescope NASA and have noticed a decrease in their periodic light (transit).

The artistic rendering of PH1, with four suns exoplanet discoveries by planet hunters (Giguere / Yale / PA)

The data showed that the planet passed in front of its parent star, a binary pair, every 138 days, eclipsing their light. The planet has been nicknamed PH1 (Planet Hunters 1) and should be a gas giant with a radius of 6.2 times that of the Earth, which makes it a little bigger than Neptune, with a mass of roughly half that of Jupiter. Binary stars are about 1.5 and 0.41 times the mass of the sun and they turn around with a period of 20 days.

The binary pairs of relatives PH1 in turn put into orbit by another binary pair of stars at a distance of 1000 times that between the Earth and the sun. If living beings could live on PH1, they do not just attend a double sunset, but they would also be able to identify two bright stars in their night sky, sailors among the stars.

The work has been confirmed by astronomers at Yale University. It was presented October 15 at the Division of the American Astronomical Society for Planetary Sciences in Reno, Nevada and the study was published in the Astrophysical Journal: Planet Hunters: A Transiting Planet in a Circumbinary Quadruple Star System: http://arxiv.org/abs/1210.3612

In addition, an independent analysis conducted by Veselin Kostov of Johns Hopkins University, also found evidence of an exoplanet is in quadruple star system. Independent confirmation of a result is an important part of the scientific process and this is one of the fastest to confirm the presence of this planet a bit exotic.

Kostov analysis corresponds very closely with the results of the Yale team, determining independently the mass and orbit of the exoplanet, despite having less data. The study will be published shortly on http://arxiv.org/.

Related links: 

American Astronomical Society for Planetary Sciences: http://dps.aas.org/

Astrophysical Journal : Planet Hunters: A Transiting Circumbinary Planet in a Quadruple Star System: http://arxiv.org/abs/1210.3612

Astrophysical Journal: http://arxiv.org/

Images, Text, Credits: Planethunters.org  / Giguere  / PA / Johns Hopkins University / Yale University / American Astronomical Society for Planetary Sciences / Orbiter.ch.

Cheers, Orbiter.ch