Resonant Removal of Exomoons During Planetary Migration
Abstract
Jupiter and Saturn play host to an impressive array of satellites, making it reasonable to suspect that similar systems of moons might exist around giant extrasolar planets. Furthermore, a significant population of such planets is known to reside at distances of several Astronomical Units (AU), leading to speculation that some moons thereof might support liquid water on their surfaces. However, giant planets are thought to undergo inward migration within their natal protoplanetary disks, suggesting that gas giants currently occupying their host star's habitable zone formed farther out. Here we show that when a moon-hosting planet undergoes inward migration, dynamical interactions may naturally destroy the moon through capture into a so-called evection resonance. Within this resonance, the lunar orbit's eccentricity grows until the moon eventually collides with the planet. Our work suggests that moons orbiting within about ~10 planetary radii are susceptible to this mechanism, with the exact number dependent on the planetary mass, oblateness, and physical size. Whether moons survive or not is critically related to where the planet began its inward migration, as well as the character of interlunar perturbations. For example, a Jupiter-like planet currently residing at 1 AU could lose moons if it formed beyond ~5 AU. Cumulatively, we suggest that an observational census of exomoons could potentially inform us on the extent of inward planetary migration, for which no reliable observational proxy currently exists.
Additional Information
© 2016 American Astronomical Society. Received 2015 October 2; accepted 2015 November 30; published 2016 January 19. C.S. acknowledges support from the NESSF student fellowship in Earth and Planetary Science. We acknowledge enlightening discussions with Dave Stevenson. We would also like to thank the referee, Matija Ćuk, for his thoughtful report that greatly improved the manuscript. This research is based in part on work supported by NSF grant AST 1517936.Attached Files
Published - Spalding_2016p18.pdf
Submitted - 1511.09472v1.pdf
Files
Name | Size | Download all |
---|---|---|
md5:16c3ae1a963017ac8295ef832f191bc0
|
957.2 kB | Preview Download |
md5:82bdb80fcff47276c2b4a2b7ccfe8cc1
|
1.5 MB | Preview Download |
Additional details
- Eprint ID
- 64987
- Resolver ID
- CaltechAUTHORS:20160303-085809609
- NASA Earth and Space Science Fellowship (NESSF)
- AST-1517936
- NSF
- Created
-
2016-03-04Created from EPrint's datestamp field
- Updated
-
2021-11-10Created from EPrint's last_modified field
- Caltech groups
- Division of Geological and Planetary Sciences