TRANSIT CONFIRMATION AND IMPROVED STELLAR AND PLANET PARAMETERS FOR THE SUPER-EARTH HD 97658 b AND ITS HOST STAR

Van Grootel, V.; Gillon, M.; Valencia, D.; Madhusudhan, N.; Dragomir, D.; Howe, A. R.; Burrows, A. S.; Demory, B.-O.; Deming, D.; Ehrenreich, D.; Lovis, C.; Mayor, M.; Pepe, F.; Queloz, D.; Scuflaire, R.; Seager, S.; Segransan, D.; Udry, S. (2014). TRANSIT CONFIRMATION AND IMPROVED STELLAR AND PLANET PARAMETERS FOR THE SUPER-EARTH HD 97658 b AND ITS HOST STAR. Astrophysical journal, 786(1), p. 2. Institute of Physics Publishing IOP 10.1088/0004-637x/786/1/2

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Super-Earths transiting nearby bright stars are key objects that simultaneously allow for accurate measurements of both their mass and radius, providing essential constraints on their internal composition. We present here the confirmation, based on Spitzer transit observations, that the super-Earth HD 97658 b transits its host star. HD 97658 is a low-mass (M* = 0.77 ± 0.05 M☉) K1 dwarf, as determined from the Hipparcos parallax and stellar evolution modeling. To constrain the planet parameters, we carry out Bayesian global analyses of Keck–High Resolution Echelle Spectrometer (Keck-HIRES) radial velocities and Microvariability and Oscillations of STars (MOST) and Spitzer photometry. HD 97658 b is a massive (MP = 7.55+0.83-0.79 M⊕) and large (RP = 2.247+0.098-0.095 R⊕ at 4.5 μm) super-Earth. We investigate the possible internal compositions for HD 97658 b. Our results indicate a large rocky component, of at least 60% by mass, and very little H–He components, at most 2% by mass. We also discuss how future asteroseismic observations can improve the knowledge of the HD 97658 system, in particular by constraining its age. Orbiting a bright host star, HD 97658 b will be a key target for upcoming space missions such as the Transiting Exoplanet Survey Satellite (TESS), the Characterizing Exoplanet Satellite (CHEOPS), the Planetary Transits and Oscillations of stars (PLATO), and the James Webb Space Telescope to characterize thoroughly its structure and atmosphere.

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:

0004-637X

Publisher:

Institute of Physics Publishing IOP

Language:

English

Submitter:

Brice-Olivier Denys Demory

Date Deposited:

06 Apr 2022 10:25

Last Modified:

02 Mar 2023 23:34

Publisher DOI:

10.1088/0004-637x/786/1/2

BORIS DOI:

10.48350/153303

URI:

https://boris.unibe.ch/id/eprint/153303

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