What is the Mass of α Cen B b?
- Creators
- Plavchan, Peter
- Chen, Xi
- Pohl, Garrett
Abstract
We investigate the possibility of constraining the sin i degeneracy of α Cen B b—with orbital period P = 3.24 days; a = 0.042 AU; m sin i = 1.1 M_⊕—to estimate the true mass of the newly reported terrestrial exoplanet in the nearest stellar system to our Sun. We present detailed numerical simulations of the dynamical stability of the exoplanet in the α Cen AB binary system for a range of initial inclinations, eccentricities, and semimajor axes. The system represents a benchmark case for the interplay of the Kozai mechanism with general relativistic and tidal forces. From our simulations, there is only a small boundary in initial inclinations and initial semimajor axes which result in the migration via the Kozai mechanism of α Cen B b to its present location. Inside this boundary, the planet orbit is stable for up to 1 Gyr against the Kozai mechanism, and outside this boundary the planet collides with α Cen B or is ejected. In our three simulations where the planet migrates in toward the star via the Kozai mechanism, the final inclination is 46°–53° relative to the AB orbital plane, lower than the initial inclination of 75° in each case. We discuss inclination constraints from the formation of α Cen B b in situ at its present location, migration in a proto-planetary disk, or migration in resonance with additional planets. We conclude that α Cen B b probably has a mass of less than 2.7 M_⊕, implying a likely terrestrial composition warranting future confirmation.
Additional Information
© 2015 The American Astronomical Society. Received 2014 November 5; accepted 2015 March 27; published 2015 June 2. We thank the anonymous referee for a thoughtful review that improved the clarity and presentation of this manuscript. The authors acknowledge Thayne Currie, Dave Latham, and David Ciardi for their encouragement in writing this paper. This research has made use of 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. P.P. acknowledges support from a NASA JPL Research and Technology Development program, and the Missouri SpaceGrant Consortium.Attached Files
Published - 0004-637X_805_2_174.pdf
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Additional details
- Alternative title
- What is the Mass of alpha Cen B beta?
- Eprint ID
- 58941
- Resolver ID
- CaltechAUTHORS:20150720-100927750
- NASA
- JPL Research and Technology Development Fund
- Missouri SpaceGrant Consortium
- Created
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2015-07-20Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field
- Caltech groups
- Infrared Processing and Analysis Center (IPAC)