MODELING KEPLER TRANSIT LIGHT CURVES AS FALSE POSITIVES: REJECTION OF BLEND SCENARIOS FOR KEPLER-9, AND VALIDATION OF KEPLER-9 d, A SUPER-EARTH-SIZE PLANET IN A MULTIPLE SYSTEM
- Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States)
- San Jose State University, San Jose, CA 95192 (United States)
- NASA Ames Research Center, Moffett Field, CA 94035 (United States)
- Las Cumbres Observatory Global Telescope, Goleta, CA 93117 (United States)
- Niels Bohr Institute, Copenhagen University, DK-2100 Copenhagen (Denmark)
- NASA Exoplanet Science Institute/Caltech, Pasadena, CA 91125 (United States)
- Lowell Observatory, Flagstaff, AZ 86001 (United States)
- University of Florida, Gainesville, FL 32611 (United States)
- Jet Propulsion Laboratory/California Institute of Technology, Pasadena, CA 91109 (United States)
- Space Telescope Science Institute, Baltimore, MD 21218 (United States)
- National Optical Astronomy Observatory, Tucson, AZ 85719 (United States)
- San Francisco State University, San Francisco, CA 94132 (United States)
Light curves from the Kepler Mission contain valuable information on the nature of the phenomena producing the transit-like signals. To assist in exploring the possibility that they are due to an astrophysical false positive, we describe a procedure (BLENDER) to model the photometry in terms of a 'blend' rather than a planet orbiting a star. A blend may consist of a background or foreground eclipsing binary (or star-planet pair) whose eclipses are attenuated by the light of the candidate and possibly other stars within the photometric aperture. We apply BLENDER to the case of Kepler-9 (KIC 3323887), a target harboring two previously confirmed Saturn-size planets (Kepler-9 b and Kepler-9 c) showing transit timing variations, and an additional shallower signal with a 1.59 day period suggesting the presence of a super-Earth-size planet. Using BLENDER together with constraints from other follow-up observations we are able to rule out all blends for the two deeper signals and provide independent validation of their planetary nature. For the shallower signal, we rule out a large fraction of the false positives that might mimic the transits. The false alarm rate for remaining blends depends in part (and inversely) on the unknown frequency of small-size planets. Based on several realistic estimates of this frequency, we conclude with very high confidence that this small signal is due to a super-Earth-size planet (Kepler-9 d) in a multiple system, rather than a false positive. The radius is determined to be 1.64{sup +0.19}{sub -0.14} R{sub +}, and current spectroscopic observations are as yet insufficient to establish its mass.
- OSTI ID:
- 21567507
- Journal Information:
- Astrophysical Journal, Vol. 727, Issue 1; Other Information: DOI: 10.1088/0004-637X/727/1/24; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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