KEPLER-21b: A 1.6 R{sub Earth} PLANET TRANSITING THE BRIGHT OSCILLATING F SUBGIANT STAR HD 179070

Journal Article · Mon Feb 20 00:00:00 EST 2012 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/746/2/123· OSTI ID:22011649

Howell, Steve B ^[1]; Rowe, Jason F; Bryson, Stephen T ^[2]; Quinn, Samuel N ^[3]; Marcy, Geoffrey W; Isaacson, Howard ^[4]; Ciardi, David R ^[5]; Chaplin, William J; Elsworth, Yvonne ^[6]; Metcalfe, Travis S ^[7]; Appourchaux, Thierry ^[8]; Basu, Sarbani ^[9]; Creevey, Orlagh L ^[10]; Gilliland, Ronald L ^[11]; Quirion, Pierre-Olivier ^[12]; Stello, Denis ^[13]; Kjeldsen, Hans; Christensen-Dalsgaard, Joergen ^[14]; Garcia, Rafael A ^[15]; others, and

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1. National Optical Astronomy Observatory, Tucson, AZ 85719 (United States)
2. NASA Ames Research Center, Moffett Field, CA 94035 (United States)
3. Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States)
4. Department of Astronomy, University of California, Berkeley, CA 94720 (United States)
5. NASA Exoplanet Science Institute/Caltech, Pasadena, CA 91125 (United States)
6. School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom)
7. High Altitude Observatory and Scientific Computing Division, National Center for Atmospheric Research, Boulder, CO 80307 (United States)
8. Institut d'Astrophysique Spatiale, Universite Paris XI-CNRS (UMR8617), Batiment 121, 91405 Orsay Cedex (France)
9. Department of Astronomy, Yale University, New Haven, CT 06520-8101 (United States)
10. Departamento de Astrofisica, Universidad de La Laguna, E-38206 La Laguna, Tenerife (Spain)
11. Space Telescope Science Institute, Baltimore, MD 21218 (United States)
12. Canadian Space Agency, 6767 Boulevard de l'Aeroport, Saint-Hubert, QC, J3Y 8Y9 (Canada)
13. Sydney Institute for Astronomy (SIfA), School of Physics, University of Sydney, NSW 2006 (Australia)
14. Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark)
15. Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot-IRFU/SAp, 91191 Gif-sur-Yvette Cedex (France)

We present Kepler observations of the bright (V = 8.3), oscillating star HD 179070. The observations show transit-like events which reveal that the star is orbited every 2.8 days by a small, 1.6 R{sub Earth} object. Seismic studies of HD 179070 using short cadence Kepler observations show that HD 179070 has a frequency-power spectrum consistent with solar-like oscillations that are acoustic p-modes. Asteroseismic analysis provides robust values for the mass and radius of HD 179070, 1.34 {+-} 0.06 M{sub Sun} and 1.86 {+-} 0.04 R{sub Sun }, respectively, as well as yielding an age of 2.84 {+-} 0.34 Gyr for this F5 subgiant. Together with ground-based follow-up observations, analysis of the Kepler light curves and image data, and blend scenario models, we conservatively show at the >99.7% confidence level (3{sigma}) that the transit event is caused by a 1.64 {+-} 0.04 R{sub Earth} exoplanet in a 2.785755 {+-} 0.000032 day orbit. The exoplanet is only 0.04 AU away from the star and our spectroscopic observations provide an upper limit to its mass of {approx}10 M{sub Earth} (2{sigma}). HD 179070 is the brightest exoplanet host star yet discovered by Kepler.

• OSTI ID: 22011649
• Journal Information: Astrophysical Journal, Vol. 746, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
IMAGES
MAGNETIC FIELDS
ORBITS
PLANETS
STARS