2023AJ....165...97R -
Astron. J., 165, 97 (2023/March-0)
A Reanalysis of the Composition of K2-106b: An Ultra-short-period Super-Mercury Candidate.
RODRIGUEZ MARTINEZ R., GAUDI B.S., SCHULZE J.G., ACUNA L., KOLECKI J., JOHNSON J.A., PAI ASNODKAR A., BOLEY K.M., DELEUIL M., MOUSIS O., PANERO W.R. and WANG J.
Abstract (from CDS):
We present a reanalysis of the K2-106 transiting planetary system, with a focus on the composition of K2-106b, an ultra-short-period, super-Mercury candidate. We globally model existing photometric and radial velocity data and derive a planetary mass and radius for K2-106b of Mp = 8.53 ± 1.02 M⊕ and ${R}_{p}={1.71}_{-0.057}^{+0.069}\,{R}_{\oplus }$, which leads to a density of ${\rho }_{p}={9.4}_{-1.5}^{+1.6}$ g cm–3, a significantly lower value than previously reported in the literature. We use planet interior models that assume a two-layer planet comprised of a liquid, pure Fe core and an iron-free, MgSiO3 mantle, and we determine that the range of the core mass fractions are consistent with the observed mass and radius. We use existing high-resolution spectra of the host star to derive the Fe/Mg/Si abundances ([Fe/H] = -0.03 ± 0.01, [Mg/H] = 0.04 ± 0.02, [Si/H] = 0.03 ± 0.06) to infer the composition of K2-106b. We find that K2-106b has a density and core mass fraction (${44}_{-15}^{+12} \% $) consistent with that of Earth (CMF⊕ = 32%). Furthermore, its composition is consistent with what is expected, assuming that it reflects the relative refractory abundances of its host star. K2-106b is therefore unlikely to be a super-Mercury, as has been suggested in previous literature.
Abstract Copyright:
© 2023. The Author(s). Published by the American Astronomical Society.
Journal keyword(s):
Exoplanet systems - Planetary interior
Simbad objects:
12
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