ASYMMETRIC TRANSIT CURVES AS INDICATION OF ORBITAL OBLIQUITY: CLUES FROM THE LATE-TYPE DWARF COMPANION IN KOI-13

Journal Article · Wed Jul 20 00:00:00 EDT 2011 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/736/1/L4· OSTI ID:21562534

Szabo, Gy M; Szabo, R; Benko, J M; Mezo, Gy; Simon, A E; Kovari, Zs; Hodosan, G; Regaly, Zs; Kiss, L L ^[1]; Lehmann, H ^[2]

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1. Konkoly Observatory of the Hungarian Academy of Sciences, P.O. Box 67, H-1525 Budapest (Hungary)
2. Thueringer Landessternwarte, 07778 Tautenburg (Germany)

KOI-13.01, a planet-sized companion in an optical double star, was announced as one of the 1235 Kepler planet candidates in 2011 February. The transit curves show significant distortion that was stable over the {approx}130 days time span of the data. Here we investigate the phenomenon via detailed analyses of the two components of the double star and a re-reduction of the Kepler data with pixel-level photometry. Our results indicate that KOI-13 is a common proper motion binary, with two rapidly rotating components (vsin i {approx} 65-70 km s{sup -1}). We identify the host star of KOI-13.01 and conclude that the transit curve asymmetry is consistent with a companion orbiting a rapidly rotating, possibly elongated star on an oblique orbit. The radius of the transiter is 2.2 R{sub J} , implying an irradiated late-type dwarf, probably a hot brown dwarf rather than a planet. KOI-13 is the first example for detecting orbital obliquity for a substellar companion without measuring the Rossiter-McLaughlin effect with spectroscopy.

• OSTI ID: 21562534
• Journal Information: Astrophysical Journal Letters, Vol. 736, Issue 1; Other Information: DOI: 10.1088/2041-8205/736/1/L4; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
BINARY STARS
DWARF STARS
ORBITS
PROPER MOTION
MOTION
STARS