Starspots and spin-orbit alignment for Kepler cool host stars

Abstract

The angle between the spin axis of the host star and the orbit of its planets (i.e., the stellar obliquity) is precious information about the formation and evolution of exoplanetary systems. Measurements of the Rossiter-McLaughlin effect revealed that many stars that host a hot-Jupiter have high obliquities, suggesting that hot-Jupiter formation involves excitation of orbital inclinations. In this contribution we show how the passage of the planet over starspots can be used to measure the obliquity of exoplanetary systems. This technique is used to obtain - for the first time - the obliquity of a system with several planets that lie in a disk, Kepler-30, with the result that the star has an obliquity smaller than 10 degrees. The implications for the formation of exoplanetary systems, in particular the hot-Jupiter population, are also discussed.

To appear in special edition of AN, proceedings of the Cool Stars 17 conference, Barcelona June 2012

References in corpus (5)

• Obliquities of Hot Jupiter host stars: Evidence for tidal interactions and primordial misalignments
• Alignment of the stellar spin with the orbits of a three-planet system
• Estimating stellar rotation from starspot detection during planetary transits
• A cool starspot or a second transiting planet in the TrES-1 system?
• A Tentative Detection of a Starspot During Consecutive Transits of an Extrasolar Planet from the Ground: No Evidence of a Double Transiting Planet System Around TrES-1

Cited by in corpus (6)

• TraMoS V. Updated ephemeris and multi-epoch monitoring of the hot Jupiters WASP-18Ab, WASP-19b, and WASP-77Ab
• Molecules as magnetic probes of starspots
• Transiting Exoplanet Monitoring Project (TEMP). II. Refined System Parameters and Transit Timing Analysis of HAT-P-33b
• Polarization in exoplanetary systems caused by transits, grazing transits, and starspots
• MANGOS II: Five new giant planets orbiting low-mass stars
• Evidence for the Late Arrival of Hot Jupiters in Systems with High Host-star Obliquities