Gillon, Michaël; Demory, Brice-Olivier; Van Grootel, Valérie; Motalebi, Fatemeh; Lovis, Christophe; Cameron, Andrew Collier; Charbonneau, David; Latham, David; Molinari, Emilio; Pepe, Francesco A.; Ségransan, Damien; Sasselov, Dimitar; Udry, Stéphane; Mayor, Michel; Micela, Giuseppina; Piotto, Giampaolo; Sozzetti, Alessandro (2017). Two massive rocky planets transiting a K-dwarf 6.5 parsecs away. Nature astronomy, 1(3) Nature Publishing Group 10.1038/s41550-017-0056
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HD 219134 is a K-dwarf star at a distance of 6.5 parsecs around which several low-mass planets were recently discovered1,2. The Spitzer Space Telescope detected a transit of the innermost of these planets, HD 219134 b, whose mass and radius (4.5 M⊕ and 1.6 R⊕ respectively) are consistent with a rocky composition1. Here, we report new high-precision time-series photometry of the star acquired with Spitzer revealing that the second innermost planet of the system, HD 219134c, is also transiting. A global analysis of the Spitzer transit light curves and the most up-to-date HARPS-N velocity data set yields mass and radius estimations of 4.74 ± 0.19 M⊕ and 1.602 ± 0.055 R⊕ for HD 219134 b, and of 4.36 ± 0.22 M⊕ and 1.511 ± 0.047 R⊕ for HD 219134 c. These values suggest rocky compositions for both planets. Thanks to the proximity and the small size of their host star (0.778 ± 0.005 R⊙)3, these two transiting exoplanets — the nearest to the Earth yet found — are well suited for a detailed characterization (for example, precision of a few per cent on mass and radius, and constraints on the atmospheric properties) that could give important constraints on the nature and formation mechanism of the ubiquitous short-period planets of a few Earth masses.
Item Type: |
Journal Article (Original Article) |
|---|---|
Division/Institute: |
10 Strategic Research Centers > Center for Space and Habitability (CSH) |
UniBE Contributor: |
Demory, Brice-Olivier Denys |
Subjects: |
500 Science > 520 Astronomy |
ISSN: |
2397-3366 |
Publisher: |
Nature Publishing Group |
Language: |
English |
Submitter: |
Brice-Olivier Denys Demory |
Date Deposited: |
04 Apr 2022 15:42 |
Last Modified: |
02 Mar 2023 23:34 |
Publisher DOI: |
10.1038/s41550-017-0056 |
BORIS DOI: |
10.48350/153290 |
URI: |
https://boris.unibe.ch/id/eprint/153290 |
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