A Collage of Small Planets from the Lick-Carnegie Exoplanet Survey: Exploring the Super-Earth and Sub-Neptune Mass Regime

Burt, Jennifer and Feng, Fabo and Holden, Bradford and Mamajek, Eric E. and Huang, Chelsea X. ORCID: https://orcid.org/0000-0003-0918-7484 and Rosenthal, Mickey M. and Wang, Songhu and Butler, R. Paul and Vogt, Steven S. and Laughlin, Gregory and Henry, Gregory W. and Teske, Johanna K. and Wang, Sharon X. and Crane, Jeffrey D. and Shectman, Steve A. (2020) A Collage of Small Planets from the Lick-Carnegie Exoplanet Survey: Exploring the Super-Earth and Sub-Neptune Mass Regime. The Astronomical Journal, 161 (1):10. pp. 1-25. ISSN 0004-6256

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Analysis of new precision radial velocity (RV) measurements from the Lick Automated Planet Finder and Keck HIRES has yielded the discovery of three new exoplanet candidates orbiting the nearby stars HD 190007 and HD 216520. We also report new velocities from the APF and the Planet Finder Spectrograph and updated orbital fits for the known exoplanet host stars GJ 686 and HD 180617. Of the newly discovered planets, HD 190007 b has a period of P = 11.72 days, an RV semiamplitude of K = 5.64 ± 0.55 m s-1, a minimum mass of M pl = 16.46 ± 1.66 M ⊕, and orbits the slightly metal-rich, active K4V star HD 190007. For HD 216520 b, we find P = 35.45 days, K = 2.28 ± 0.20 m s-1, and M pl = 10.26 ± 0.99 M ⊕, while for HD 216520 c, P = 154.43 days, K = 1.29 ± 0.22 m s-1, and M pl = 9.44 ± 1.63 M ⊕. Both planets orbit the slightly metal-poor, inactive K0V star HD 216520. Our updated best-fit models for HD 180617 b and GJ 686 b are in good agreement with the published results. For HD 180617 b, we obtain P = 105.91 days and M pl = 12.214 ± 1.05 M ⊕. For GJ 686 b, we find P = 15.53 days and M pl = 6.624 ± 0.432 M ⊕. Using an injection-recovery exercise, we find that HD 190007 b and HD 216520 b are unlikely to have additional planets with masses and orbital periods within a factor of 2, in marked contrast to ∼85% of planets in this mass and period range discovered by Kepler.

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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Published version deposited in accordance with the copyright policy of the publisher.
Faculty/School / Institute/Centre: No Faculty
Faculty/School / Institute/Centre: No Faculty
Date Deposited: 04 Apr 2022 00:23
Last Modified: 13 Apr 2022 01:21
Uncontrolled Keywords: Exoplanet astronomy (486); Exoplanet detection methods (489); Exoplanets (498); Radial velocity (1332); Mini Neptunes (1063); Astrophysics - Earth and Planetary Astrophysics
Fields of Research (2020): 51 PHYSICAL SCIENCES > 5101 Astronomical sciences > 510109 Stellar astronomy and planetary systems
Identification Number or DOI: https://doi.org/10.3847/1538-3881/abc2d0
URI: http://eprints.usq.edu.au/id/eprint/47433

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