تقرير
An Earth-sized exoplanet with a Mercury-like composition
| العنوان: | An Earth-sized exoplanet with a Mercury-like composition |
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| المؤلفون: | Santerne, A., Brugger, B., Armstrong, D. J., Adibekyan, V., Lillo-Box, J., Gosselin, H., Aguichine, A., Almenara, J. -M., Barrado, D., Barros, S. C. C., Bayliss, D., Boisse, I., Bonomo, A. S., Bouchy, F., Brown, D. J. A., Deleuil, M., Mena, E. Delgado, Demangeon, O., Díaz, R. F., Doyle, A., Dumusque, X., Faedi, F., Faria, J. P., Figueira, P., Foxell, E., Giles, H., Hébrard, G., Hojjatpanah, S., Hobson, M., Jackman, J., King, G., Kirk, J., Lam, K. W. F., Ligi, R., Lovis, C., Louden, T., McCormac, J., Mousis, O., Neal, J. J., Osborn, H. P., Pepe, F., Pollacco, D., Santos, N. C., Sousa, S. G., Udry, S., Vigan, A. |
| المصدر: | Nature Astronomy volume 2, pages 393-400 (2018) |
| سنة النشر: | 2018 |
| المجموعة: | Astrophysics |
| مصطلحات موضوعية: | Astrophysics - Earth and Planetary Astrophysics |
| الوصف: | The Earth, Venus, Mars, and some extrasolar terrestrial planets have a mass and radius that is consistent with a mass fraction of about 30% metallic core and 70% silicate mantle. At the inner frontier of the solar system, Mercury has a completely different composition, with a mass fraction of about 70% metallic core and 30% silicate mantle. Several formation or evolution scenarios are proposed to explain this metal-rich composition, such as a giant impact, mantle evaporation, or the depletion of silicate at the inner-edge of the proto-planetary disk. These scenarios are still strongly debated. Here we report the discovery of a multiple transiting planetary system (K2-229), in which the inner planet has a radius of 1.165+/-0.066 Rearth and a mass of 2.59+/-0.43 Mearth. This Earth-sized planet thus has a core-mass fraction that is compatible with that of Mercury, while it was expected to be similar to that of the Earth based on host-star chemistry. This larger Mercury analogue either formed with a very peculiar composition or it has evolved since, e.g. by losing part of its mantle. Further characterisation of Mercury-like exoplanets like K2-229 b will help putting the detailed in-situ observations of Mercury (with Messenger and BepiColombo) into the global context of the formation and evolution of solar and extrasolar terrestrial planets. Comment: Accepted preprint in Nature Astronomy. Publisher-edited version available at http://rdcu.be/JRE7 Supplement materials available at https://www.nature.com/articles/s41550-018-0420-5 |
| نوع الوثيقة: | Working Paper |
| DOI: | 10.1038/s41550-018-0420-5 |
| URL الوصول: | http://arxiv.org/abs/1805.08405 |
| رقم الأكسشن: | edsarx.1805.08405 |
| قاعدة البيانات: | arXiv |
| DOI: | 10.1038/s41550-018-0420-5 |
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