分类： 天文学 >> 天文学 提交时间： 2023-02-19
Robert C. Frazier
Gudmundur Stefansson
Suvrath Mahadevan
Samuel W. Yee
Caleb I. Canas
Josh Winn
Jacob Luhn
Fei Dai
Lauren Doyle
Heather Cegla
Shubham Kanodia
Paul Robertson
John Wisniewski
Chad Bender
Jiayin Dong
Arvind F. Gupta
Samuel Halverson
Suzanne Hawley
Leslie Hebb
Rae Holcomb
摘要： TOI-2076 b is a sub-Neptune-sized planet ($R= 2.39 \pm 0.10 {R_\oplus}$) that transits a young ($204 \pm 50 {MYr}$) bright ($V = 9.2$) K-dwarf hosting a system of three transiting planets. Using spectroscopic observations with the NEID spectrograph on the WIYN 3.5 m Telescope, we model the Rossiter-McLaughlin effect of TOI-2076 b, and derive a sky-projected obliquity of $\lambda=-3_{-15}^{+16\:\circ}$. Using the size of the star ($R=0.775 \pm0.015 {R_\odot}$), and the stellar rotation period ($P_{\mathrm{rot}}=7.27\pm0.23$ days), we estimate an obliquity of $\psi=18_{-9}^{+10\:\circ}$ ($\psi < 34^\circ$ at 95\% confidence), demonstrating that TOI-2076 b is on a well-aligned orbit. Simultaneous diffuser-assisted photometry from the 3.5 m Telescope at Apache Point Observatory rules out flares during the transit. TOI-2076 b joins a small but growing sample of young planets in compact multi-planet systems with well-aligned orbits, and is the fourth planet with an age $\lesssim 300$ Myr in a multi-transiting system with an obliquity measurement. The low obliquity of TOI-2076 b and the presence of transit timing variations in the system suggest the TOI-2076 system likely formed via convergent disk migration in an initially well-aligned disk.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Shubham Kanodia
Suvrath Mahadevan
Jessica Libby-Roberts
Gudmundur Stefansson
Caleb I. Canas
Anjali A. A. Piette
Alan Boss
Johanna Teske
John Chambers
Greg Zeimann
Andrew Monson
Paul Robertson
Joe P. Ninan
Andrea S. J. Lin
Chad F. Bender
William D. Cochran
Scott A. Diddams
Arvind F. Gupta
Samuel Halverson
Suzanne Hawley
摘要： We present the discovery of TOI-5205~b, a transiting Jovian planet orbiting a solar metallicity M4V star, which was discovered using Transiting Exoplanet Survey Satellite photometry and then confirmed using a combination of precise radial velocities, ground-based photometry, spectra, and speckle imaging. TOI-5205~b has one of the highest mass ratios for M dwarf planets with a mass ratio of almost 0.3$\%$, as it orbits a host star that is just $0.392 \pm 0.015$ \solmass{}. Its planetary radius is $1.03 \pm 0.03~R_J$, while the mass is $1.08 \pm 0.06~M_J$. Additionally, the large size of the planet orbiting a small star results in a transit depth of $\sim 7\%$, making it one of the deepest transits of a confirmed exoplanet orbiting a main-sequence star. The large transit depth makes TOI-5205~b a compelling target to probe its atmospheric properties, as a means of tracing the potential formation pathways. While there have been radial-velocity-only discoveries of giant planets around mid-M dwarfs, this is the first transiting Jupiter with a mass measurement discovered around such a low-mass host star. The high mass of TOI-5205~b stretches conventional theories of planet formation and disk scaling relations that cannot easily recreate the conditions required to form such planets.
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