Consequences of an eccentric orbit for Fomalhaut b
Abstract
Fomalhaut b is currently the least massive, directly imaged exoplanet candidate. New observation epochs have revealed this object to be moving on a highly eccentric orbit, which sets important new constraints. I consider scenarios where Fomalhaut b is the only object interacting with the debris disc, and ones involving an additional unseen planet. I also investigate the possibility that Fomalhaut b is merely a transient dust cloud in light of the revised eccentric orbit. I argue that the scenario best able to match the observational constraints is a super-Earth Fomalhaut b surrounded by a vast cloud of dust that is generated by a population of irregular satellites, with an undetected ∼Saturn-mass planet orbiting interior to the disc and driving the secular dynamics. Testable predictions are summarized that could differentiate between this scenario and other possibilities.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- March 2014
- DOI:
- 10.1093/mnras/stt2473
- arXiv:
- arXiv:1312.7020
- Bibcode:
- 2014MNRAS.438.3577T
- Keywords:
-
- celestial mechanics;
- planets and satellites: dynamical evolution and stability;
- planet-disc interactions;
- Astrophysics - Earth and Planetary Astrophysics
- E-Print:
- 25 pages, 6 figures. Accepted for publication in MNRAS