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Title: Transit and radial velocity survey efficiency comparison for a habitable zone Earth

Transit and radial velocity searches are two techniques for identifying nearby extrasolar planets to Earth that transit bright stars. Identifying a robust sample of these exoplanets around bright stars for detailed atmospheric characterization is a major observational undertaking. In this study we describe a framework that answers the question of whether a transit or radial velocity survey is more efficient at finding transiting exoplanets given the same amount of observing time. Within the framework we show that a transit survey's window function can be approximated using the hypergeometric probability distribution. We estimate the observing time required for a transit survey to find a transiting Earth-sized exoplanet in the habitable zone (HZ) with an emphasis on late-type stars. We also estimate the radial velocity precision necessary to detect the equivalent HZ Earth-mass exoplanet that also transits when using an equal amount of observing time as the transit survey. We find that a radial velocity survey with σ{sub rv} ∼ 0.6 m s{sup –1} precision has comparable efficiency in terms of observing time to a transit survey with the requisite photometric precision σ{sub phot} ∼ 300 ppm to find a transiting Earth-sized exoplanet in the HZ of late M dwarfs. For super-Earths,more » a σ{sub rv} ∼ 2.0 m s{sup –1} precision radial velocity survey has comparable efficiency to a transit survey with σ{sub phot} ∼ 2300 ppm.« less
Authors:
 [1] ;  [2]
  1. SETI Institute/NASA Ames Research Center, Moffett Field, CA 94035 (United States)
  2. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
Publication Date:
OSTI Identifier:
22365181
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 792; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCURACY; APPROXIMATIONS; COMPARATIVE EVALUATIONS; DISTRIBUTION; ECLIPSE; EFFICIENCY; MASS; PLANETS; PROBABILITY; RADIAL VELOCITY; STARS