Publication Date:
2013-11-01
Description:
Recent analyses of data from the NASA Kepler spacecraft have established that planets with radii within 25 per cent of the Earth's (R Earth symbol) are commonplace throughout the Galaxy, orbiting at least 16.5 per cent of Sun-like stars. Because these studies were sensitive to the sizes of the planets but not their masses, the question remains whether these Earth-sized planets are indeed similar to the Earth in bulk composition. The smallest planets for which masses have been accurately determined are Kepler-10b (1.42 R Earth symbol) and Kepler-36b (1.49 R Earth symbol), which are both significantly larger than the Earth. Recently, the planet Kepler-78b was discovered and found to have a radius of only 1.16 R Earth symbol. Here we report that the mass of this planet is 1.86 Earth masses. The resulting mean density of the planet is 5.57 g cm(-3), which is similar to that of the Earth and implies a composition of iron and rock.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Pepe, Francesco -- Cameron, Andrew Collier -- Latham, David W -- Molinari, Emilio -- Udry, Stephane -- Bonomo, Aldo S -- Buchhave, Lars A -- Charbonneau, David -- Cosentino, Rosario -- Dressing, Courtney D -- Dumusque, Xavier -- Figueira, Pedro -- Fiorenzano, Aldo F M -- Gettel, Sara -- Harutyunyan, Avet -- Haywood, Raphaelle D -- Horne, Keith -- Lopez-Morales, Mercedes -- Lovis, Christophe -- Malavolta, Luca -- Mayor, Michel -- Micela, Giusi -- Motalebi, Fatemeh -- Nascimbeni, Valerio -- Phillips, David -- Piotto, Giampaolo -- Pollacco, Don -- Queloz, Didier -- Rice, Ken -- Sasselov, Dimitar -- Segransan, Damien -- Sozzetti, Alessandro -- Szentgyorgyi, Andrew -- Watson, Christopher A -- England -- Nature. 2013 Nov 21;503(7476):377-80. doi: 10.1038/nature12768. Epub 2013 Oct 30.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Observatoire Astronomique de l'Universite de Geneve, 51 chemin des Maillettes, 1290 Versoix, Switzerland.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24172902" target="_blank"〉PubMed〈/a〉
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
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