학술논문
TOI-3757 b: A low density gas giant orbiting a solar-metallicity M dwarf
Document Type
Working Paper
Author
Kanodia, Shubham; Libby-Roberts, Jessica; Canas, Caleb I.; Ninan, Joe P.; Mahadevan, Suvrath; Stefansson, Gudmundur; Lin, Andrea S. J.; Jones, Sinclaire; Monson, Andrew; Parker, Brock A.; Kobulnicky, Henry A.; Swaby, Tera N.; Powers, Luke; Beard, Corey; Bender, Chad F.; Blake, Cullen H.; Cochran, William D.; Dong, Jiayin; Diddams, Scott A.; Fredrick, Connor; Gupta, Arvind F.; Halverson, Samuel; Hearty, Fred; Logsdon, Sarah E.; Metcalf, Andrew J.; McElwain, Michael W.; Morley, Caroline; Rajagopal, Jayadev; Ramsey, Lawrence W.; Robertson, Paul; Roy, Arpita; Schwab, Christian; Terrien, Ryan C.; Wisniewski, John; Wright, Jason T.
Source
The Astronomical Journal, Volume 164, Number 3 (2022 AJ 164 81)
Subject
Language
Abstract
We present the discovery of a new Jovian-sized planet, TOI-3757 b, the lowest density planet orbiting an M dwarf (M0V). It orbits a solar-metallicity M dwarf discovered using TESS photometry and confirmed with precise radial velocities (RV) from HPF and NEID. With a planetary radius of $12.0^{+0.4}_{-0.5}$ $R_{\oplus}$ and mass of $85.3^{+8.8}_{-8.7}$ $M_{\oplus}$, not only does this object add to the small sample of gas giants ($\sim 10$) around M dwarfs, but also, its low density ($\rho =$ $0.27^{+0.05}_{-0.04}$ $\textrm{g~cm}^{-3}$) provides an opportunity to test theories of planet formation. We present two hypotheses to explain its low density; first, we posit that the low metallicity of its stellar host ($\sim$ 0.3 dex lower than the median metallicity of M dwarfs hosting gas giants) could have played a role in the delayed formation of a solid core massive enough to initiate runaway accretion. Second, using the eccentricity estimate of $0.14 \pm 0.06$ we determine it is also plausible for tidal heating to at least partially be responsible for inflating the radius of TOI-3757b b. The low density and large scale height of TOI-3757 b makes it an excellent target for transmission spectroscopy studies of atmospheric escape and composition (TSM $\sim$ 190). We use HPF to perform transmission spectroscopy of TOI-3757 b using the helium 10830 \AA~ line. Doing this, we place an upper limit of 6.9 \% (with 90\% confidence) on the maximum depth of the absorption from the metastable transition of He at $\sim$ 10830 \AA, which can help constraint the atmospheric mass loss rate in this energy limited regime.
Comment: AJ. arXiv admin note: text overlap with arXiv:2107.13670
Comment: AJ. arXiv admin note: text overlap with arXiv:2107.13670