THE IMPACT OF HOT JUPITERS ON THE SPIN-DOWN OF THEIR HOST STARS
- Harvard-Smithsonian Center for Astrophysics, 60 Garden St. Cambridge, MA 02138 (United States)
- Center for Space Environment Modeling, University of Michigan, 2455 Hayward St., Ann Arbor, MI 48109 (United States)
We present a numerical magnetohydrodynamic study of the dependence of stellar mass and angular momentum loss rates on the orbital distance to close-in giant planets. We find that the mass loss rate drops by a factor of {approx}1.5-2, while the angular momentum loss rate drops by a factor of {approx}4 as the distance decreases past the Alfven surface. This reduction in angular momentum loss is due to the interaction between the stellar and planetary Alfven surfaces, which modifies the global structure of the stellar corona and stellar wind on the hemisphere facing the planet, as well as on the opposite hemisphere. The simulation also shows that the magnitude of change in angular momentum loss rate depends mostly on the strength of the planetary magnetic field and not on its polarity. The interaction, however, begins at greater separation if the overall field topology of the star and the planet are anti-aligned. Our results are consistent with evidence for excess angular momentum in stars harboring close-in giant planets and show that the reduction in wind-driven angular momentum loss can compete with, and perhaps dominate, spin-up due to tidal interaction.
- OSTI ID:
- 21452713
- Journal Information:
- Astrophysical Journal Letters, Vol. 723, Issue 1; Other Information: DOI: 10.1088/2041-8205/723/1/L64; ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
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