Exoplanets & Exomoons

A Transiting Super-Earth in the Radius Valley and An Outer Planet Candidate Around HD 307842

By Keith Cowing
Status Report
astro-ph.EP
June 26, 2023
Filed under , , , , , ,
A Transiting Super-Earth in the Radius Valley and An Outer Planet Candidate Around HD 307842
The result of the transit injection-and-recovery test for the planet candidate. Blue to light green represents an increasing detection possibility of its transit signal (assuming it transits). The solid blue histogram in the top panel illustrates the average number of transits within the TESS time baseline. The foreground yellow solid lines mark the six possible orbital solutions of the planet candidate found in Juliet. — astro-ph.EP

We report the confirmation of a TESS-discovered transiting super-Earth planet orbiting a mid-G star, HD 307842 (TOI-784). The planet has a period of 2.8 days, and the radial velocity (RV) measurements constrain the mass to be 9.67+0.83/-0.82 [Earth Masses].

We also report the discovery of an additional planet candidate on an outer orbit that is most likely non-transiting. The possible periods of the planet candidate are approximately 20 to 63 days, with the corresponding RV semi-amplitudes expected to range from 3.2 to 5.4 m/s and minimum masses from 12.6 to 31.1 [Earth Masses].

The radius of the transiting planet (planet b) is 1.93+0.11/-0.09 [Earth Radii], which results in a mean density of 7.4+1.4/-1.2 g/cm^3 suggesting that TOI-784b is likely to be a rocky planet though it has a comparable radius to a sub-Neptune. We found TOI-784b is located at the lower edge of the so-called “radius valley” in the radius vs. insolation plane, which is consistent with the photoevaporation or core-powered mass loss prediction.

The TESS data did not reveal any significant transit signal of the planet candidate, and our analysis shows that the orbital inclinations of planet b and the planet candidate are 88.60+0.84/-0.86 degrees and <= 88.3-89.2 degrees, respectively. More RV observations are needed to determine the period and mass of the second object, and search for additional planets in this system.

Xinyan Hua, Sharon Xuesong Wang, Johanna K. Teske, Tianjun Gan, Avi Shporer, George Zhou, Keivan G. Stassun, Markus Rabus, Steve B. Howell, Carl Ziegler, Jack J. Lissauer, Joshua N. Winn, Jon M. Jenkins, Eric B. Ting, Karen A. Collins, Andrew W. Mann, Wei Zhu, Su Wang, R. Paul Butler, Jeffrey D. Crane, Stephen A. Shectman, Luke G. Bouma, Cesar Briceno, Diana Dragomir, William Fong, Nicholas Law, Jennifer V. Medina, Samuel N. Quinn, George R. Ricker, Richard P. Schwarz, Sara Seager, Ramotholo Sefako, Chris Stockdale, Roland Vanderspek, Joel Villasenor

Comments: 30 pages, 21 figures, accepted for publication in AJ
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2306.14655 [astro-ph.EP] (or arXiv:2306.14655v1 [astro-ph.EP] for this version)
Submission history
From: Xinyan Hua
[v1] Mon, 26 Jun 2023 12:47:57 UTC (7,165 KB)
https://arxiv.org/abs/2306.14655
Astrobiology

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻