HOT STARS WITH HOT JUPITERS HAVE HIGH OBLIQUITIES
- Department of Physics, Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)
- Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
- Department of Astrophysics, NASA Exoplanet Science Institute, California Institute of Technology, MC 249-17, Pasadena, CA 91125 (United States)
We show that stars with transiting planets for which the stellar obliquity is large are preferentially hot (T{sub eff} > 6250 K). This could explain why small obliquities were observed in the earliest measurements, which focused on relatively cool stars drawn from Doppler surveys, as opposed to hotter stars that emerged more recently from transit surveys. The observed trend could be due to differences in planet formation and migration around stars of varying mass. Alternatively, we speculate that hot-Jupiter systems begin with a wide range of obliquities, but the photospheres of cool stars realign with the orbits due to tidal dissipation in their convective zones, while hot stars cannot realign because of their thinner convective zones. This in turn would suggest that hot Jupiters originate from few-body gravitational dynamics and that disk migration plays at most a supporting role.
- OSTI ID:
- 21451008
- Journal Information:
- Astrophysical Journal Letters, Vol. 718, Issue 2; Other Information: DOI: 10.1088/2041-8205/718/2/L145; ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
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