Hubble Space Telescope search for the transit of the Earth-mass exoplanet Centauri B b
Author(s)Demory, B.-O.; Ehrenreich, D.; Queloz, D.; Gilliland, R.; Chaplin, W. J.; Proffitt, C.; Gillon, M.; Gunther, M. N.; Benneke, B.; Dumusque, X.; Lovis, C.; Pepe, F.; Segransan, D.; Udry, S.; Seager, Sara; Triaud, Amaury; ... Show more Show less
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Results from exoplanet surveys indicate that small planets (super-Earth size and below) are abundant in our Galaxy. However, little is known about their interiors and atmospheres. There is therefore a need to find small planets transiting bright stars, which would enable a detailed characterization of this population of objects. We present the results of a search for the transit of the Earth-mass exoplanet α Centauri B b with the Hubble Space Telescope (HST). We observed α Centauri B twice in 2013 and 2014 for a total of 40 h. We achieve a precision of 115 ppm per 6-s exposure time in a highly saturated regime, which is found to be consistent across HST orbits. We rule out the transiting nature of α Centauri B b with the orbital parameters published in the literature at 96.6 per cent confidence. We find in our data a single transit-like event that could be associated with another Earth-sized planet in the system, on a longer period orbit. Our programme demonstrates the ability of HST to obtain consistent, high-precision photometry of saturated stars over 26 h of continuous observations.
DepartmentMassachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences; Massachusetts Institute of Technology. Department of Physics; MIT Kavli Institute for Astrophysics and Space Research
Monthly Notices of the Royal Astronomical Society
Oxford University Press
Demory, B.-O., D. Ehrenreich, D. Queloz, et al. “Hubble Space Telescope Search for the Transit of the Earth-Mass Exoplanet Centauri B b.” Monthly Notices of the Royal Astronomical Society, vol. 450, no. 2, 2015, pp. 2043–2051.
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