Three short-period Jupiters from TESS

Abstract

We report the confirmation and mass determination of three hot Jupiters discovered by the Transiting Exoplanet Survey Satellite (TESS) mission: HIP 65Ab (TOI-129, TIC-201248411) is an ultra-short-period Jupiter orbiting a bright (V = 11.1 mag) K4-dwarf every 0.98 days. It is a massive 3.213 ± 0.078 MJ planet in a grazing transit configuration with an impact parameter of b = 1.17−0.08+0.10. As a result the radius is poorly constrained, 2.03−0.49+0.61RJ. The planet’s distance to its host star is less than twice the separation at which it would be destroyed by Roche lobe overflow. It is expected to spiral into HIP 65A on a timescale ranging from 80 Myr to a few gigayears, assuming a reduced tidal dissipation quality factor of Qs′ = 107 − 109. We performed a full phase-curve analysis of the TESS data and detected both illumination- and ellipsoidal variations as well as Doppler boosting. HIP 65A is part of a binary stellar system, with HIP 65B separated by 269 AU (3.95 arcsec on sky). TOI-157b (TIC 140691463) is a typical hot Jupiter with a mass of 1.18 ± 0.13 MJ and a radius of 1.29 ± 0.02 RJ. It has a period of 2.08 days, which corresponds to a separation of just 0.03 AU. This makes TOI-157 an interesting system, as the host star is an evolved G9 sub-giant star (V = 12.7). TOI-169b (TIC 183120439) is a bloated Jupiter orbiting a V = 12.4 G-type star. It has a mass of 0.79 ±0.06 MJ and a radius of 1.09−0.05+0.08RJ. Despite having the longest orbital period (P = 2.26 days) of the three planets, TOI-169b receives the most irradiation and is situated on the edge of the Neptune desert. All three host stars are metal rich with [Fe / H] ranging from 0.18 to0.24.

Empirical limb-darkening coefficients & transit parameters of known exoplanets from TESS

“…• For TOI-157 b, our value for a/R * of 6.30 ± 0.09 is inconsistent at 3-sigma with that reported in Nielsen et al (2020) of 5.79 +0.07 −0.07 . One of the differences between our analyses is that Nielsen et al (2020) use, along some ground-based photometric follow-up, 8-sectors-worth of 30-min cadence data and 4-sectors-worth of 2-min cadence data, which arguably mostly define the planetary properties. In our analysis, however, we use 12-sectorsworth of 2-minute cadence data.…”

“…It is interesting to note, in addition, that the differences on this parameter between the Nielsen et al (2020) estimate and our work go in the same direction as those observed and discussed for K2-237 b before: our analysis obtains a larger value for a/R * . The only observational similarity between the TESS observations of TOI-157 b analyzed by Nielsen et al (2020) and the K2 observations of K2-237 b analyzed by the teams of Soto et al (2018) and Smith et al (2019) is that both datasets rely heavily on longcadence data. This is suspiciously consistent with what is expected by morphological lightcurve distortions due to finite integration time (Kipping 2010): not properly accounting/resampling the lightcurves in long-cadence observations would give rise to smaller values of a/R * for a fixed period.…”

The Solar Neighborhood XLIX: Nine Giant Planets Orbiting Nearby K Dwarfs, and the CHIRON Spectrograph's Radial Velocity Performance

“…A total of 58 spectroscopic observations have been secured between 2018 September 8 to 2020 January 12 and we find an RV signal consistent with the TESS transit signal detected. Our analysis yields to a giant planet companion with mass 2.95 M Jup in an orbital period of 0.981 days, consistent with the orbit published by Nielsen et al (2020). The properties of the ∼1 day orbit and massive planet make this an excellent candidate for detailed exoplanet atmospheric studies.…”

Gemini/GMOS Transmission Spectroscopy of the Grazing Planet Candidate WD 1856+534 b

“…Besides WASP-67b and WD 1856+534 b, some ∼ 20 confirmed exoplanets undergo grazing transits (Davis et al 2020). Recently, TESS has detected several hot giant planets with grazing transits around bright stars, including TOI 216 b (Kipping et al 2019;Dawson et al 2019), TOI 1130 c (Huang et al 2020), HIP 65Ab (Nielsen et al 2020), andTOI 564 b (Davis et al 2020). These planets are excellent targets for grazing transit spectroscopy.…”