Abstract
cent analyses 1, 2, 3, 4 of data from the NASA Kepler spacecraft5 have established that planets with radii within 25 per cent of the Earth’s ( ) are commonplace throughout the Galaxy, orbiting at least 16.5 per cent of Sun-like stars1. 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 determined6, 7 are Kepler-10b (1.42 ) and Kepler-36b (1.49 ), which are both significantly larger than the Earth. Recently, the planet Kepler-78b was discovered8 and found to have a radius of only 1.16 . 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.
Originalsprog | Engelsk |
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Tidsskrift | Nature |
Vol/bind | 503 |
Udgave nummer | 7476 |
Sider (fra-til) | 377-380 |
Antal sider | 4 |
ISSN | 0028-0836 |
DOI | |
Status | Udgivet - 21 nov. 2013 |