分类： 天文学 >> 天文学 提交时间： 2023-02-19
Caleb I. Cañas
Shubham Kanodia
Jessica Libby-Roberts
Andrea S. J. Lin
Maria Schutte
Luke Powers
Sinclaire Jones
Andrew Monson
Songhu Wang
Guðmundur Stefánsson
William D. Cochran
Paul Robertson
Suvrath Mahadevan
Adam F. Kowalski
John Wisniewski
Brock A. Parker
Alexander Larsen
Franklin A. L. Chapman
Henry A. Kobulnicky
Arvind F. Gupta
摘要： We confirm the planetary nature of two gas giants discovered by TESS to transit M dwarfs with stellar companions at wide separations. TOI-3984 A ($J=11.93$) is an M4 dwarf hosting a short-period ($4.353326 \pm 0.000005$ days) gas giant ($M_p=0.14\pm0.03~\mathrm{M_{J}}$ and $R_p=0.71\pm0.02~\mathrm{R_{J}}$) with a wide separation white dwarf companion. TOI-5293 A ($J=12.47$) is an M3 dwarf hosting a short-period ($2.930289 \pm 0.000004$ days) gas giant ($M_p=0.54\pm0.07~\mathrm{M_{J}}$ and $R_p=1.06\pm0.04~\mathrm{R_{J}}$) with a wide separation M dwarf companion. We characterize both systems using a combination of ground-based and space-based photometry, speckle imaging, and high-precision radial velocities from the Habitable-zone Planet Finder and NEID spectrographs. TOI-3984 A b ($T_{eq}=563\pm15$ K and $\mathrm{TSM}=138_{-27}^{+29}$) and TOI-5293 A b ($T_{eq}=675_{-30}^{+42}$ K and $\mathrm{TSM}=92\pm14$) are two of the coolest gas giants among the population of hot Jupiter-sized gas planets orbiting M dwarfs and are favorable targets for atmospheric characterization of temperate gas giants and three-dimensional obliquity measurements to probe system architecture and migration scenarios.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Andrea S. J. Lin
Jessica E. Libby-Roberts
Jaime A. Alvarado-Montes
Caleb I. Cañas
Shubham Kanodia
Leslie Hebb
Eric L. N. Jensen
Suvrath Mahadevan
Luke C. Powers
Tera N. Swaby
John Wisniewski
Corey Beard
Chad F. Bender
Cullen H. Blake
William D. Cochran
Scott A. Diddams
Robert C. Frazier
Connor Fredrick
Michael Gully-Santiago
Samuel Halverson
摘要： TOI-1899~b is a rare exoplanet, a temperate Warm Jupiter orbiting an M-dwarf, first discovered by \citet{Canas2020_toi1899} from a TESS single-transit event. Using new radial velocities (RVs) from the precision RV spectrographs HPF and NEID, along with additional TESS photometry and ground-based transit follow-up, we are able to derive a much more precise orbital period of $P = 29.090312_{-0.000035}^{+0.000036}$~d, along with a radius of $R_p = 0.99\pm0.03$~\unit{R_{J}}. We have also improved the constraints on planet mass, $M_p = 0.67\pm{0.04}$~\unit{M_{J}}, and eccentricity, which is consistent with a circular orbit at 2$\sigma$ ($e = 0.044_{-0.027}^{+0.029}$). TOI-1899~b occupies a unique region of parameter space as the coolest known ($T_{eq} \approx$ 380~K) Jovian-sized transiting planet around an M-dwarf; we show that it has great potential to provide clues regarding the formation and migration mechanisms of these rare gas giants through transmission spectroscopy with JWST as well as studies of tidal evolution.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Jessica E. Libby-Roberts
Maria Schutte
Leslie Hebb
Shubham Kanodia
Caleb Canas
Gudmundur Stefansson
Andrea S. J. Lin
Suvrath Mahadevan
Winter Parts
Luke Powers
John Wisniewski
Chad F. Bender
William D. Cochran
Scott A. Diddams
Mark E. Everett
Arvind F. Gupta
Samuel Halverson
Henry A. Kobulnicky
Adam F. Kowalski
Alexander Larsen
摘要： We perform an in-depth analysis of the recently validated TOI-3884 system, an M4 dwarf star with a transiting super-Neptune. Using high precision light curves obtained with the 3.5 m Apache Point Observatory and radial velocity observations with the Habitable-zone Planet Finder (HPF), we derive a planetary mass of 32.6$^{+7.3}_{-7.4}$ M$_{\oplus}$ and radius of 6.4 $\pm$ 0.2 R$_{\oplus}$. We detect a distinct star spot crossing event occurring just after ingress and spanning half the transit for every transit. We determine this spot feature to be wavelength-dependent with the amplitude and duration evolving slightly over time. Best-fit star spot models show that TOI-3884b possesses a misaligned ($\lambda$ = 75 $\pm$ 10$^\circ$) orbit which crosses a giant pole-spot. This system presents a rare opportunity for studies into the nature of both a misaligned super-Neptune and spot evolution on an active mid-M dwarf.
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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