[en] Short-period super-Earths and Neptunes are now known to be very frequent around solar-type stars. Improving our understanding of these mysterious planets requires the detection of a significant sample of objects suitable for detailed characterization. Searching for the transits of the low-mass planets detected by Doppler surveys is a straightforward way to achieve this goal. Indeed, Doppler surveys target the most nearby main-sequence stars, they regularly detect close-in low-mass planets with significant transit probability, and their radial velocity data constrain strongly the ephemeris of possible transits. In this context, we initiated in 2010 an ambitious Spitzer multi-Cycle transit search project that targeted 25 low-mass planets detected by radial velocity, focusing mainly on the shortest-period planets detected by the HARPS spectrograph. We report here null results for 19 targets of the project. For 16 planets out of 19, a transiting configuration is strongly disfavored or firmly rejected by our data for most planetary compositions. We derive a posterior probability of 83% that none of the probed 19 planets transits (for a prior probability of 22%), which still leaves a significant probability of 17% that at least one of them does transit. Globally, our Spitzer project revealed or confirmed transits for three of its 25 targeted planets, and discarded or disfavored the transiting nature of 20 of them. Our light curves demonstrate for Warm Spitzer excellent photometric precisions: for 14 targets out of 19, we were able to reach standard deviations that were better than 50 ppm per 30 min intervals. Combined with its Earth-trailing orbit, which makes it capable of pointing any star in the sky and to monitor it continuously for days, this work confirms Spitzer as an optimal instrument to detect sub-mmag-deep transits on the bright nearby stars targeted by Doppler surveys. The photometric and radial velocity time series used in this work are only available at the CDS via anonymous ftp to <A href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A> (<A href="http://130.79.128.5">http://130.79.128.5</A>) or via <A href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/601/A117">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/601/A117</A>
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Gillon, Michaël ; Université de Liège > Département d'astrophys., géophysique et océanographie (AGO) > Origines Cosmologiques et Astrophysiques (OrCa)
Demory, B.-O.; University of Bern, Center for Space and Habitability, Sidlerstrasse 5, 3012, Bern, Switzerland ; Cavendish Laboratory, J. J. Thomson Avenue, Cambridge, CB3 0HE, UK
Lovis, C.; Observatoire de Genève, Université de Genève, 51 Chemin des Maillettes, 1290, Sauverny, Switzerland
Deming, D.; Department of Astronomy, University of Maryland, College Park, MD, 20742-2421, USA
Ehrenreich, D.; Observatoire de Genève, Université de Genève, 51 Chemin des Maillettes, 1290, Sauverny, Switzerland
Lo Curto, G.; European Southern Observatory, Karl-Schwarzschild-Str. 2, 85478, Garching bei München, Germany
Mayor, M.; Observatoire de Genève, Université de Genève, 51 Chemin des Maillettes, 1290, Sauverny, Switzerland
Pepe, F.; Observatoire de Genève, Université de Genève, 51 Chemin des Maillettes, 1290, Sauverny, Switzerland
Queloz, D.; Cavendish Laboratory, J. J. Thomson Avenue, Cambridge, CB3 0HE, UK ; Observatoire de Genève, Université de Genève, 51 Chemin des Maillettes, 1290, Sauverny, Switzerland
Seager, S.; Department of Earth, Atmospheric and Planetary Sciences, Department of Physics, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA, 02139, USA
Ségransan, D.; Observatoire de Genève, Université de Genève, 51 Chemin des Maillettes, 1290, Sauverny, Switzerland
Udry, S.; Observatoire de Genève, Université de Genève, 51 Chemin des Maillettes, 1290, Sauverny, Switzerland)
Language :
English
Title :
The Spitzer search for the transits of HARPS low-mass planets. II. Null results for 19 planets
Lanotte, A., Gillon, M., Demory, B.-O. et al., 2014 b, A&A, 572, A73
LoCurto G., Mayor, M., Benz, W. et al., 2010, A&A, 512, A48
Lo Curto, G., Mayor, M., Benz, W. et al., 2013, A&A, 551, A59
Lovis, C., Ségransan, D., Mayor, M. et al., 2011, A&A, 528, A112
Mandel, J., & Agol, E. 2002, ApJ, 580, 171
Mayor, M., Pepe, F., Queloz, D. et al., 2003, The Messenger, 114, 20
Mayor, M., Marnier, M., Lovis, C., et al. 2011, ArXiv e-prints [arXiv:1109.2497]
Melo, C., Santos, N. C., Gieren, W. et al., 2007, A&A, 467, 721
Meschiari, S., Wolf, A. S., Rivera, E. et al., 2009, PASP, 121, 1016
Motalebi, F., Udry, S., Gillon, M. et al., 2015, A&A, 584, A72
Press, W. H., Teukolsky, S. A., Vetterling, W. T., & Flannery, B. P. 1992, Numerical Recipes in Fortan 77: The Art of Scientific Computing (Cambridge Universty Press)
Queloz, D., Henry, G. W., Sivan, J. P. et al., 2001, A&A, 379, 279
Rafikov, R. R. 2006, ApJ, 648, 666
Rivera, E. J, Butler, R. P., Vogt, S. S. et al., 2010, ApJ, 708, 1492
Rowe, J. F., Bryson, S. T., Marcy, G. W. et al., 2014, ApJ, 784, 45
Santos, N. C., Bouchy, F., Mayor, M. et al., 2004, A&A, 426, L19
Santos, N. C., Sousa, S. G., Mortier, A. et al., 2013, A&A, 556, A150
Santos, N. C., Santerne, A., Faria, J. P. et al., 2016, A&A, 592, A13
Schwarz, G. E. 1978, Annals of Statistics, 6, 461
Seager, S. 2010, Exoplanet Atmospheres (Princeton University Press)
Seager, S., Kuchner, M., Hier-Majumder, C. A., & Militzer, B. 2007, ApJ, 669, 1279
Skrutskie, M. F., Cutri, R. M., Stiening, R. et al., 2006, AJ, 131, 1163
Stevens, D. J., & Gaudi, B. S. 2013, PASP, 125, 933
Stevenson, K. B., Harrington, J., Nymeyer, S. et al., 2010, Nature, 464, 1161
Stevenson, K. B., Harrington, J., Fortney, J. et al., 2012, ApJ, 754, 136
Stetson, P. B. 1987, PASP, 99, 111
Valencia, D., Guillot, T., Parmentier, V., & Freedman, R. S. 2013, ApJ, 775, 10
Van Grootel, V., Gillon, M., Valencia, D. et al., 2014, ApJ, 786, 2
Van Leeuwen, F. 2007, A&A, 474, 653
Vogt, S. S., Wittenmeyer, R. A., Butler, R. P. et al., 2010, ApJ, 708, 1366
Wisniewski, J. P., Ge, J., Crepp, J. R. et al., 2012, AJ, 143, 107
Winn, J. N., Matthews, J. M., Dawson, R. I. et al., 2011, ApJ, 733, L18