The NEID Earth Twin Survey. I. Confirmation Of A 31-day Planet Orbiting HD 86728
With close to three years of observations in hand, the NEID Earth Twin Survey (NETS) is starting to unearth new astrophysical signals for a curated sample of bright, radial velocity (RV)-quiet stars.
We present the discovery of the first NETS exoplanet, HD 86728 b, a mpsini=9.16+0.55−0.56 M⊕ planet on a circular, P=31.1503+0.0062−0.0066 d orbit, thereby confirming a candidate signal identified by Hirsch et al. (2021).
We confirm the planetary origin of the detected signal, which has a semi-amplitude of just K=1.91+0.11−0.12 m s−1, via careful analysis of the NEID RVs and spectral activity indicators, and we constrain the mass and orbit via fits to NEID and archival RV measurements.
The host star is intrinsically quiet at the ∼1 m s−1 level, with the majority of this variability likely stemming from short-timescale granulation. HD 86728 b is among the small fraction of exoplanets with similar masses and periods that have no known planetary siblings.
Masses and periods of exoplanets orbiting FGK dwarfs with (red) and without (blue) other known planetary companions in the same system. The grey dashed box highlights exoplanets with masses and periods similar to HD 86728 b (5 M⊕ < mp sin i < 15 M⊕; 20 d < P < 50 d). We differentiate between planets for which the true mass is known (e.g., transiting planets) and planets for which there exists a mass-inclination degeneracy. The former are shown as squares and the latter as circles. HD 86728 b is in the minority of planets in this region without known siblings. The small red and blue markers indicate planets that fall outside the defined mass-period space or that orbit non-FGK host stars. — astro-ph.EP
Arvind F. Gupta, Jacob K. Luhn, Jason T. Wright, Suvrath Mahadevan, Paul Robertson, Daniel M. Krolikowski, Eric B. Ford, Caleb I. Cañas, Samuel Halverson, Andrea S.J. Lin, Shubham Kanodia, Evan Fitzmaurice, Christian Gilbertson, Chad F. Bender, Cullen H. Blake, Jiayin Dong, Mark R. Giovinazzi, Sarah E. Logsdon, Andrew Monson, Joe P. Ninan, Jayadev Rajagopal, Arpita Roy, Christian Schwab, Guðmundur Stefánsson
Comments: Submitted to AAS Journals. 18 pages, 10 figures, 3 tables, 1 appendix
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2409.12315 [astro-ph.EP] (or arXiv:2409.12315v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2409.12315
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Submission history
From: Arvind Gupta
[v1] Wed, 18 Sep 2024 21:07:24 UTC (1,972 KB)
https://arxiv.org/abs/2409.12315
Astrobiology,
