Dynamical Packing in the Habitable Zone: The Case of Beta CVn
Abstract
Uncovering the occurrence rate of terrestrial planets within the habitable zone (HZ) of their host stars has been a particular focus of exoplanetary science in recent years. The statistics of these occurrence rates have largely been derived from transiting planet discoveries, and have uncovered numerous HZ planets in compact systems around M-dwarf host stars. Here we explore the width of the HZ as a function of spectral type, and the dynamical constraints on the number of stable orbits within the HZ for a given star. We show that, although the Hill radius for a given planetary mass increases with larger semimajor axis, the width of the HZ for earlier-type stars allows for more terrestrial planets in the HZ than late-type stars. In general, dynamical constraints allow ~6 HZ Earth-mass planets for stellar masses ≳0.7M⊙, depending on the presence of farther out giant planets. As an example, we consider the case of Beta CVn, a nearby bright solar-type star. We present 20 yr of radial velocities (RV) from the Keck/High Resolution Echelle Spectrometer (HIRES) and Automated Planet Finder (APF) instruments and conduct an injection-recovery analysis of planetary signatures in the data. Our analysis of these RV data rule out planets more massive than Saturn within 10 au of the star. These system properties are used to calculate the potential dynamical packing of terrestrial planets in the HZ and show that such nearby stellar targets could be particularly lucrative for HZ planet detection by direct imaging exoplanet missions.
Additional Information
© 2020 The American Astronomical Society. Received 2020 May 26; revised 2020 June 19; accepted 2020 June 23; published 2020 July 27. The authors would like to thank Paul Dalba, Joshua Pepper, and the anonymous referee for the constructive feedback on the manuscript. We also thank Debra Fischer, John Johnson, Kathryn Peek, and Jason Wright for their contributions to the Keck observations. We gratefully acknowledge the efforts and dedication of the Keck Observatory staff for support of HIRES and remote observing. We recognize and acknowledge the cultural role and reverence that the summit of Maunakea has within the indigenous Hawaiian community. We are deeply grateful to have the opportunity to conduct observations from this mountain. We thank Ken and Gloria Levy, who supported the construction of the Levy Spectrometer on the Automated Planet Finder. We thank the University of California and Google for supporting Lick Observatory and the UCO staff for their dedicated work scheduling and operating the telescopes of Lick Observatory. This research has made use of the following archives: the Habitable Zone Gallery at hzgallery.org and the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. The results reported herein benefited from collaborations and/or information exchange within NASA's Nexus for Exoplanet System Science (NExSS) research coordination network sponsored by NASA's Science Mission Directorate. Software: Mercury (Chambers 1999), RadVel (Fulton et al. 2018).Attached Files
Published - Kane_2020_AJ_160_81.pdf
Accepted Version - 2006.13962.pdf
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Additional details
- Eprint ID
- 104584
- Resolver ID
- CaltechAUTHORS:20200727-092618134
- University of California
- Caltech
- NASA
- Created
-
2020-07-28Created from EPrint's datestamp field
- Updated
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2021-11-16Created from EPrint's last_modified field
- Caltech groups
- Astronomy Department, Infrared Processing and Analysis Center (IPAC)