STARSPOTS, SPIN-ORBIT MISALIGNMENT, AND ACTIVE LATITUDES IN THE HAT-P-11 EXOPLANETARY SYSTEM

Journal Article · Sat Dec 10 04:00:00 EST 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/743/1/61· OSTI ID:22004525

Sanchis-Ojeda, Roberto; Winn, Joshua N ^[1]

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1. Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

We present the analysis of four months of Kepler photometry of the K4V star HAT-P-11, including 26 transits of its 'super-Neptune' planet. The transit data exhibit numerous anomalies which we interpret as passages of the planet over dark starspots. These spot-crossing anomalies preferentially occur at two specific phases of the transit. These phases can be understood as the intersection points between the transit chord and the active latitudes of the host star, where starspots are most abundant. Based on the measured characteristics of spot-crossing anomalies and previous observations of the Rossiter-McLaughlin effect, we find two solutions for the stellar obliquity {psi} and active latitude l: either {psi} = 106{sup +15}{sub -11} and l = 19.7{sup +1.5}{sub -2.2}, or {psi} = 97{sup +8}{sub -4} and l = 67{sup +2}{sub -4} (all in degrees). If the active latitude changes with time analogous to the 'butterfly diagram' of the Sun's activity cycle, future observations should reveal changes in the preferred phases of spot-crossing anomalies.

• OSTI ID: 22004525
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 743; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ORBITS
PHOTOMETRY
PLANETS
ROTATION
STARSPOTS
SUN