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K2-291b: A Rocky Super-Earth in a 2.2 day Orbit
Name
Kosiarek_2019_AJ_157_116.pdf
Description
Published version
Size
2.79 MB
Format
Adobe PDF
Checksum (MD5)
1f6f67aef51f968e28738e0a4456f076
Journal
Astronomical Journal
Publisher
American Astronomical Society
Version
Final published version
Abstract
© 2019. The American Astronomical Society. All rights reserved.. K2-291 is a solar-type star with a radius of R ∗ = 0.899 ±0.034 R and mass of M ∗ = 0.934 ±0.038 M . From the K2 C13 data, we found one super-Earth planet (R p = 1.589 -0.072+0.095 R ⊕ ) transiting this star on a short period orbit (P = 2.225177 -6.8e-5+6.6e-5 days). We followed this system up with adaptive-optic imaging and spectroscopy to derive stellar parameters, search for stellar companions, and determine a planet mass. From our 75 radial velocity measurements using High Resolution Echelle Spectrometer on Keck I and High Accuracy Radial velocity Planet Searcher in the northern hemisphere on Telescopio Nazionale Galileo, we constrained the mass of K2-291 b to M p = 6.49 ±1.16 M ⊕ . We found it necessary to model correlated stellar activity radial velocity signals with a Gaussian process (GP) in order to more accurately model the effect of stellar noise on our data; the addition of the GP also improved the precision of this mass measurement. With a bulk density of ρ = 8.84 -2.03+2.50 g cm -3 , the planet is consistent with an Earth-like rock/iron composition and no substantial gaseous envelope. Such an envelope, if it existed in the past, was likely eroded away by photoevaporation during the first billion years of the star's lifetime.
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DOI of Published Version
10.3847/1538-3881/AAFE83
