Warning: This document, and the Nature papers to which it refers, may contain information that is price sensitive (as legally defined, for example, in the UK Criminal Justice Act 1993 Part V) with respect to publicly quoted companies. Anyone dealing in securities using information contained in this document or in advanced copies of Nature’s content may be guilty of insider trading under the US Securities Exchange Act of 1934.
PICTURES: While we are happy for images from Nature to be reproduced for the purposes of contemporaneous news reporting, you must also seek permission from the copyright holder (if named) or author of the research paper in question (if not).
HYPE: We take great care not to hype the papers mentioned on our press releases, but are sometimes accused of doing so. If you ever consider that a story has been hyped, please do not hesitate to contact us at [email protected], citing the specific example.
--------------------------------------------------------------------------------
Planetary science: Detection of two Earth-sized exoplanets (AOP)
DOI: 10.1038/nature10780
The discovery of two Earth-size planets orbiting a Sun-like star called Kepler-20 is reported online this week by Nature. The paper describes observations made by the Kepler spacecraft and methods used to determine that the signals detected are planets. Moreover, the researchers go on to predict that these planets are rocky, with possible Earth-like compositions.
Since the discovery of the first extrasolar giant planets orbiting Sun-like stars around two decades ago, steady improvements in observational capabilities have brought us closer to detecting Earth-like planets. François Fressin and co-workers report the detection of the smallest exoplanets discovered so far, orbiting around Kepler-20 — a star already known to host three larger transiting planets. The authors rule out hypotheses that the signals might not be planets, and calculate the size of the planets as they pass in front of (transit) the parent star. One of these planets, Kepler-20 f, has a radius almost identical to Earth’s and the other, Kepler-20 e, is slightly smaller at 0.87 times the radius of Earth.
Fressin and colleagues infer that the planets may have bulk compositions similar to Earth, such as a 32% iron core and a 68% silicate mantle, based on their Earth-like radii. Furthermore, they suggest that the outer planet (Kepler-20 f) may have developed a thick water-vapour atmosphere.
CONTACT
François Fressin (Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, USA)
Tel: +1 617 496 7299; E-mail: [email protected]
-------------------------------------------------------------------------------
PRESS CONTACTS…
From North America and Canada
Neda Afsarmanesh, Nature New York
Tel: +1 212 726 9231; E-mail: [email protected]
From Japan, Korea, China, Singapore and Taiwan
Mika Nakano, Nature Tokyo
Tel: +81 3 3267 8751; E-mail: [email protected]
From the UK
Rebecca Walton, Nature, London
Tel: +44 20 7843 4502; E-mail: [email protected]
------------------------------------------------------------------------------
About Nature Publishing Group (NPG):
Nature Publishing Group (NPG) is a publisher of high impact scientific and medical information in print and online. NPG publishes journals, online databases and services across the life, physical, chemical and applied sciences and clinical medicine.
Focusing on the needs of scientists, Nature (founded in 1869) is the leading weekly, international scientific journal. In addition, for this audience, NPG publishes a range of Nature research journals and Nature Reviews journals, plus a range of prestigious academic journals including society-owned publications. Online, nature.com provides over 5 million visitors per month with access to NPG publications and online databases and services, including Nature News and NatureJobs plus access to Nature Network and Nature Education’s Scitable.com.
Scientific American is at the heart of NPG’s newly-formed consumer media division, meeting the needs of the general public. Founded in 1845, Scientific American is the oldest continuously published magazine in the US and the leading authoritative publication for science in the general media. Together with scientificamerican.com and 15 local language editions around the world it reaches over 3 million consumers and scientists. Other titles include Scientific American Mind and Spektrum der Wissenschaft in Germany.
Throughout all its businesses NPG is dedicated to serving the scientific and medical communities and the wider scientifically interested general public. Part of Macmillan Publishers Limited, NPG is a global company with principal offices in London, New York and Tokyo, and offices in cities worldwide including Boston, Buenos Aires, Delhi, Hong Kong, Madrid, Barcelona, Munich, Heidelberg, Basingstoke, Melbourne, Paris, San Francisco, Seoul and Washington DC. For more information, please go to www.nature.com.
