Water Covered Earth-Like Planet Discovered

(midnight. – promoted by ek hornbeck)

The science journal Nature reported in a study published Wednesday that a new Earth-like planet that is larger than Earth and appearing to be more than half covered with water, and possibly with conditions allowing the existence of life, has been discovered by graduate student Zachory Berta, a co-author on the paper submitted to Nature with David Charbonneau, head of the MEarth Project of the Harvard-Smithsonian Center for Astrophysics (CfA), a joint collaboration between the Smithsonian Astrophysical Observatory and the Harvard College Observatory.

The UK’s Guardian has the story:

A giant waterworld that is wet to its core has been spotted in orbit around a dim but not too distant star, improving the odds that habitable planets may exist in our cosmic neighbourhood.

The planet is nearly three times as large as Earth and made almost entirely of water, forming a global ocean more than 15,000km deep.

Astronomers detected the alien world as it passed in front of its sun, a red dwarf star 40 light years away in a constellation called Ophiuchus, after the Greek for “snake holder”.

The discovery, made with a network of amateur telescopes, is being hailed as a major step forward in the search for planets beyond our solar system that are hospitable to life as we know it.

[snip]

The latest planet is only a stone’s throw away in astronomical terms, meaning scientists will be able to turn the Hubble Space Telescope towards it and analyse its atmosphere, potentially revealing signs of life. Charbonneau’s team has already requested time on the space telescope.

“Using the Hubble, we can look at the atmosphere and say not only whether it’s habitable, but whether it’s inhabited,” Charbonneau told the Guardian. “If we find oxygen in the atmosphere things will get really interesting, because on Earth all the oxygen in the atmosphere comes from life.”

AFP also reporting on the the Nature paper says:

The so-called “super Earth” is about 42 light years away in another solar system and has a radius nearly 2.7 times larger than that of our planet, according to the study by the Harvard-Smithsonian Centre for Astrophysics.

The discovery of the planet, called GJ 1214b, represents a “major step forward” in the search for worlds similar to the Earth, added the University of California’s Geoffrey Marcy in a commentary also in Nature.

The “newfound world” is too hot to sustain life as we know it, said the Harvard-Smithsonian Centre for Astrophysics in a statement.

Its density suggests however it “is composed of about three-fourths water and other ices and one fourth-rock,” it said. “There are also tantalising hints that the planet has a gaseous atmosphere.”

Its temperature is estimated at between 280 and 120 degrees Celsius (536 and 248 degrees Fahrenheit) with its host star about one-fifth the size of the Sun, according to the scientists.

The Nature paper is only available to Nature subscribers, but the abstract is publicly accessible:

A super-Earth transiting a nearby low-mass star

David Charbonneau1, Zachory K. Berta1, Jonathan Irwin1, Christopher J. Burke1, Philip Nutzman1, Lars A. Buchhave1,2, Christophe Lovis3, Xavier Bonfils3,4, David W. Latham1, Stéphane Udry3, Ruth A. Murray-Clay1, Matthew J. Holman1, Emilio E. Falco1, Joshua N. Winn5, Didier Queloz3, Francesco Pepe3, Michel Mayor3, Xavier Delfosse4 & Thierry Forveille4

  1. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138 USA

  2. Niels Bohr Institute, Copenhagen University, Juliane Maries Vej 30, DK-2100 Copenhagen, Denmark

  3. Observatoire de Genève, Université de Genève, 51 chemin des Maillettes, 1290 Sauverny, Switzerland

  4. Université Joseph Fourier – Grenoble 1, Centre national de la recherche scientifique, Laboratoire d’Astrophysique de Grenoble (LAOG), UMR 5571, 38041 Grenoble Cedex 09, France

  5. Department of Physics, Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA

Correspondence to: David Charbonneau1 Correspondence and requests for materials should be addressed to D.C. (Email: [email protected]).

Abstract

A decade ago, the detection of the first transiting extrasolar planet provided a direct constraint on its composition and opened the door to spectroscopic investigations of extrasolar planetary atmospheres3. Because such characterization studies are feasible only for transiting systems that are both nearby and for which the planet-to-star radius ratio is relatively large, nearby small stars have been surveyed intensively. Doppler studies and microlensing have uncovered a population of planets with minimum masses of 1.9-10 times the Earth’s mass [], called super-Earths. The first constraint on the bulk composition of this novel class of planets was afforded by CoRoT-7b (refs 8, 9), but the distance and size of its star preclude atmospheric studies in the foreseeable future. Here we report observations of the transiting planet GJ 1214b, which has a mass of 6.55M and a radius 2.68 times Earth’s radius [], indicating that it is intermediate in stature between Earth and the ice giants of the Solar System. We find that the planetary mass and radius are consistent with a composition of primarily water enshrouded by a hydrogen-helium envelope that is only 0.05% of the mass of the planet. The atmosphere is probably escaping hydrodynamically, indicating that it has undergone significant evolution during its history. The star is small and only 13 parsecs away, so the planetary atmosphere is amenable to study with current observatories.