Starspots, spin-orbit misalignment, and active latitudes in the HAT-P-11 exoplanetary system
Author(s)
Sanchis Ojeda, Roberto
Winn, Joshua Nathan
Date Issued
November 2011
Journal
Astrophysical Journal
Publisher
IOP Publishing
Citation
Sanchis-Ojeda, Roberto, and Joshua N. Winn. “Starspots, spin-orbit misalignment, and active latitudes in the HAT-P-11 exoplanetary system.” The Astrophysical Journal 743.1 (2011): 61.
Version
Author's final manuscript
Abstract
We present the analysis of 4 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 that 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 spotcrossing
anomalies, and previous observations of the Rossiter-McLaughlin effect, we find two solutions for
the stellar obliquity ψ and active latitude l: either ψ = 106[superscript +15 over
-11] and l = 19.7[superscript +1.5 over
-2.2], or ψ = 97[superscript +8
over -4] and l = 67[superscript +2 over
-4] (all in
degrees). If the active latitude changes with time in analogy with the “butterfly diagram” of the Sun’s activity
cycle, future observations should reveal changes in the preferred phases of spot-crossing anomalies.
Subject headings: planetary systems—stars: individual (HAT-P-11), rotation, spots, activity
MIT Department
Massachusetts Institute of Technology. Department of Physics
MIT Kavli Institute for Astrophysics and Space Research
Terms of Use
Creative Commons Attribution-Noncommercial-Share Alike 3.0
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1088/0004-637x/743/1/61
