TOI-3235 b: a transiting giant planet around an M4 dwarf star

分类： 天文学 >> 天文学 提交时间： 2023-02-19

Melissa J. Hobson Andrés Jordán E. M. Bryant R. Brahm D. Bayliss J. D. Hartman G. Á. Bakos Th. Henning Jose Manuel Almenara Khalid Barkaoui Zouhair Benkhaldoun Xavier Bonfils François Bouchy David Charbonneau Marion Cointepas Karen A. Collins Jason D. Eastman Mourad Ghachoui Michaël Gillon Robert F. Goeke

摘要： We present the discovery of TOI-3235 b, a short-period Jupiter orbiting an M-dwarf with a stellar mass close to the critical mass at which stars transition from partially to fully convective. TOI-3235 b was first identified as a candidate from TESS photometry, and confirmed with radial velocities from ESPRESSO, and ground-based photometry from HATSouth, MEarth-South, TRAPPIST-South, LCOGT, and ExTrA. We find that the planet has a mass of $\mathrm{0.665\pm0.025\,M_J}$ and a radius of $\mathrm{1.017\pm0.044\,R_J}$. It orbits close to its host star, with an orbital period of $\mathrm{2.5926\,d}$, but has an equilibrium temperature of $\mathrm{\approx 604 \, K}$, well below the expected threshold for radius inflation of hot Jupiters. The host star has a mass of $\mathrm{0.3939\pm0.0030\,M_\odot}$, a radius of $\mathrm{0.3697\pm0.0018\,R_\odot}$, an effective temperature of $\mathrm{3389 \, K}$, and a J-band magnitude of $\mathrm{11.706\pm0.025}$. Current planet formation models do not predict the existence of gas giants such as TOI-3235 b around such low-mass stars. With a high transmission spectroscopy metric, TOI-3235 b is one of the best-suited giants orbiting M-dwarfs for atmospheric characterization.

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