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Title: 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

Abstract

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. Basedmore » 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.« less

Authors:
; ; ; ; ;  [1];  [2]; ; ;  [3];  [4];  [5];  [6];  [7];  [8];  [9];  [10];  [11];  [12]
  1. Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States)
  2. San Jose State University, San Jose, CA 95192 (United States)
  3. NASA Ames Research Center, Moffett Field, CA 94035 (United States)
  4. Las Cumbres Observatory Global Telescope, Goleta, CA 93117 (United States)
  5. Niels Bohr Institute, Copenhagen University, DK-2100 Copenhagen (Denmark)
  6. NASA Exoplanet Science Institute/Caltech, Pasadena, CA 91125 (United States)
  7. Lowell Observatory, Flagstaff, AZ 86001 (United States)
  8. University of Florida, Gainesville, FL 32611 (United States)
  9. Jet Propulsion Laboratory/California Institute of Technology, Pasadena, CA 91109 (United States)
  10. Space Telescope Science Institute, Baltimore, MD 21218 (United States)
  11. National Optical Astronomy Observatory, Tucson, AZ 85719 (United States)
  12. San Francisco State University, San Francisco, CA 94132 (United States)
Publication Date:
OSTI Identifier:
21567507
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 727; Journal Issue: 1; Other Information: DOI: 10.1088/0004-637X/727/1/24; Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BINARY STARS; ECLIPSE; PHOTOMETRY; PLANETS; SIMULATION; STARS

Citation Formats

Torres, Guillermo, Fressin, Francois, Charbonneau, David, Fabrycky, Daniel C, Holman, Matthew J, Latham, David W, Batalha, Natalie M, Borucki, William J, Bryson, Stephen T, Koch, David G, Brown, Timothy M, Buchhave, Lars A, Ciardi, David R, Dunham, Edward W, Ford, Eric B, Gautier, III, Thomas N, Gilliland, Ronald L, Howell, Steve B, Isaacson, Howard, and Jenkins, Jon M., E-mail: gtorres@cfa.harvard.edu. 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. United States: N. p., 2011. Web. doi:10.1088/0004-637X/727/1/24.
Torres, Guillermo, Fressin, Francois, Charbonneau, David, Fabrycky, Daniel C, Holman, Matthew J, Latham, David W, Batalha, Natalie M, Borucki, William J, Bryson, Stephen T, Koch, David G, Brown, Timothy M, Buchhave, Lars A, Ciardi, David R, Dunham, Edward W, Ford, Eric B, Gautier, III, Thomas N, Gilliland, Ronald L, Howell, Steve B, Isaacson, Howard, & Jenkins, Jon M., E-mail: gtorres@cfa.harvard.edu. 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. United States. https://doi.org/10.1088/0004-637X/727/1/24
Torres, Guillermo, Fressin, Francois, Charbonneau, David, Fabrycky, Daniel C, Holman, Matthew J, Latham, David W, Batalha, Natalie M, Borucki, William J, Bryson, Stephen T, Koch, David G, Brown, Timothy M, Buchhave, Lars A, Ciardi, David R, Dunham, Edward W, Ford, Eric B, Gautier, III, Thomas N, Gilliland, Ronald L, Howell, Steve B, Isaacson, Howard, and Jenkins, Jon M., E-mail: gtorres@cfa.harvard.edu. 2011. "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". United States. https://doi.org/10.1088/0004-637X/727/1/24.
@article{osti_21567507,
title = {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},
author = {Torres, Guillermo and Fressin, Francois and Charbonneau, David and Fabrycky, Daniel C and Holman, Matthew J and Latham, David W and Batalha, Natalie M and Borucki, William J and Bryson, Stephen T and Koch, David G and Brown, Timothy M and Buchhave, Lars A and Ciardi, David R and Dunham, Edward W and Ford, Eric B and Gautier, III, Thomas N and Gilliland, Ronald L and Howell, Steve B and Isaacson, Howard and Jenkins, Jon M., E-mail: gtorres@cfa.harvard.edu},
abstractNote = {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.},
doi = {10.1088/0004-637X/727/1/24},
url = {https://www.osti.gov/biblio/21567507}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 1,
volume = 727,
place = {United States},
year = {Thu Jan 20 00:00:00 EST 2011},
month = {Thu Jan 20 00:00:00 EST 2011}
}