ON THE SPIN-ORBIT MISALIGNMENT OF THE XO-3 EXOPLANETARY SYSTEM
- Department of Physics, and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)
- Institute for Astronomy, University of Hawaii, Honolulu, HI 96822 (United States)
- Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
- Department of Astronomy, University of California, Mail Code 3411, Berkeley, CA 94720 (United States)
- National Astronomical Observatory of Japan, Osawa, Mitaka, Tokyo 181-8588 (Japan)
- Department of Astronomy, University of California, 430 Portola Plaza, Box 951547, Los Angeles, CA (United States)
- Department of Physics, University of Tokyo, Tokyo 113-0033 (Japan)
- Princeton University Observatory, Princeton, NJ 08544 (United States)
We present photometric and spectroscopic observations of the 2009 February 2 transit of the exoplanet XO-3b. The new data show that the planetary orbital axis and stellar rotation axis are misaligned, as reported earlier by Hebrard and coworkers. We find the angle between the sky projections of the two axes to be 37.3 {+-} 3.7 deg., as compared to the previously reported value of 70 {+-} 15 deg. The significance of this discrepancy is unclear because there are indications of systematic effects. XO-3b is the first exoplanet known to have a highly inclined orbit relative to the equatorial plane of its parent star, and as such it may fulfill the predictions of some scenarios for the migration of massive planets into close-in orbits. We revisit the statistical analysis of spin-orbit alignment in hot-Jupiter systems. Assuming the stellar obliquities to be drawn from a single Rayleigh distribution, we find the mode of the distribution to be 13{sup +5}{sub -2} deg. However, it remains the case that a model representing two different migration channels-in which some planets are drawn from a perfectly aligned distribution and the rest are drawn from an isotropic distribution-is favored over a single Rayleigh distribution.
- OSTI ID:
- 21313898
- Journal Information:
- Astrophysical Journal, Vol. 700, Issue 1; Other Information: DOI: 10.1088/0004-637X/700/1/302; Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
Similar Records
The dedicated monitor of exotransits (DEMONEX): Seven transits of XO-4b
Magnetic and gravitational disk-star interactions: an interdependence of PMS stellar rotation rates and spin-orbit misalignments