Gravity-darkened Seasons: Insolation Around Rapid Rotators
Abstract
I model the effect of rapid stellar rotation on a planet’s insolation. Fast-rotating stars have induced pole-to-equator temperature gradients (known as gravity darkening) of up to several thousand Kelvin that affect the star’s luminosity and peak emission wavelength as a function of latitude. When orbiting such a star, a planet’s annual insolation can strongly vary depending on its orbital inclination. Specifically, inclined orbits result in temporary exposure to the star’s hotter poles. I find that gravity darkening can drive changes in a planet’s equilibrium temperature of up to ∼15% due to increased irradiance near the stellar poles. This effect can also vary a planet’s exposure to UV radiation by up to ∼80% throughout its orbit as it is exposed to an irradiance spectrum corresponding to different stellar effective temperatures over time.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- November 2016
- DOI:
- 10.3847/0004-637X/832/1/93
- arXiv:
- arXiv:1609.07106
- Bibcode:
- 2016ApJ...832...93A
- Keywords:
-
- planet–star interactions;
- planets and satellites: atmospheres;
- planets and satellites: physical evolution;
- Astrophysics - Earth and Planetary Astrophysics
- E-Print:
- 8 pages, 6 figures, accepted for publication in ApJ