Abstract
Abstract We present Keck/KPIC Phase II K-band observations of the nontransiting hot Jupiter HD 143105 b. Using a cross-correlation approach, we make the first detection of the planetary atmosphere at K p = 18 5 − 13 + 11 km s−1 and an inferior conjunction time 2.5 hr before the previously published ephemeris. The retrieved K p value, in combination with the orbital period, mass of the host star, and lack of transit detection, give an orbital inclination of 7 8 − 12 ∘ + 2 and a true planet mass of 1.23 ± 0.10 M J. While the equilibrium temperature of HD 143105 b is in the transition regime between noninverted and inverted atmospheres, our analysis strongly prefers a noninverted atmosphere. Retrieval analysis indicates the atmosphere of HD 143105 b is cloud free to approximately 1 bar and dominated by H2O absorption ( logH 2 O MMR = − 3 . 9 − 0.5 + 0.8 ), placing only an upper limit on the CO abundance ( logCO MMR < − 3.7 at 95% confidence). We place no constraints on the abundances of Fe, Mg, or 13CO. From these abundances, we place an upper limit on the carbon-to-oxygen ratio for HD 143105 b, C/O < 0.2 at 95% confidence, and find the atmospheric metallicity is approximately 0.1 × solar. The low metallicity may be responsible for the lack of a thermal inversion, which at the temperature of HD 143105 b would likely require significant opacity from TiO and/or VO. With these results, HD 143105 b joins the small number of nontransiting hot Jupiters with detected atmospheres.
Published Version
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