Publication Date:
2015-11-13
Description:
M-dwarf stars--hydrogen-burning stars that are smaller than 60 per cent of the size of the Sun--are the most common class of star in our Galaxy and outnumber Sun-like stars by a ratio of 12:1. Recent results have shown that M dwarfs host Earth-sized planets in great numbers: the average number of M-dwarf planets that are between 0.5 to 1.5 times the size of Earth is at least 1.4 per star. The nearest such planets known to transit their star are 39 parsecs away, too distant for detailed follow-up observations to measure the planetary masses or to study their atmospheres. Here we report observations of GJ 1132b, a planet with a size of 1.2 Earth radii that is transiting a small star 12 parsecs away. Our Doppler mass measurement of GJ 1132b yields a density consistent with an Earth-like bulk composition, similar to the compositions of the six known exoplanets with masses less than six times that of the Earth and precisely measured densities. Receiving 19 times more stellar radiation than the Earth, the planet is too hot to be habitable but is cool enough to support a substantial atmosphere, one that has probably been considerably depleted of hydrogen. Because the host star is nearby and only 21 per cent the radius of the Sun, existing and upcoming telescopes will be able to observe the composition and dynamics of the planetary atmosphere.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Berta-Thompson, Zachory K -- Irwin, Jonathan -- Charbonneau, David -- Newton, Elisabeth R -- Dittmann, Jason A -- Astudillo-Defru, Nicola -- Bonfils, Xavier -- Gillon, Michael -- Jehin, Emmanuel -- Stark, Antony A -- Stalder, Brian -- Bouchy, Francois -- Delfosse, Xavier -- Forveille, Thierry -- Lovis, Christophe -- Mayor, Michel -- Neves, Vasco -- Pepe, Francesco -- Santos, Nuno C -- Udry, Stephane -- Wunsche, Anael -- England -- Nature. 2015 Nov 12;527(7577):204-7. doi: 10.1038/nature15762.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA. ; Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138, USA. ; Observatoire de Geneve, Universite de Geneve, 51 chemin des Maillettes, 1290 Sauverny, Switzerland. ; Universite Grenoble Alpes, IPAG, F-38000 Grenoble, France. ; CNRS, IPAG, F-38000 Grenoble, France. ; Institut d'Astrophysique et de Geophysique, Universite de Liege, Allee du 6 Aout 17, Batiment B5C, 4000 Liege, Belgium. ; Institute for Astronomy, University of Hawaii at Manoa, Honolulu, Hawaii 96822, USA. ; Laboratoire d'Astrophysique de Marseille, UMR 6110 CNRS, Universite de Provence, 38 rue Frederic Joliot-Curie, 13388, Marseille Cedex 13, France. ; Departamento de Fisica, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, Rio Grande do Norte, Brazil. ; Instituto de Astrofisica e Ciencias do Espaco, Universidade do Porto, CAUP, Rua das Estrelas, 4150-762 Porto, Portugal. ; Departamento de Fisica e Astronomia, Faculdade de Ciencias, Universidade do Porto, Rua Campo Alegre, 4169-007 Porto, Portugal.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26560298" 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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