Scattered Light from Close-in Extrasolar Planets: Prospects of Detection with the MOST Satellite

Abstract

The ultra-precise photometric space satellite MOST (Microvariability and Oscillations of STars) will provide the first opportunity to measure the albedos and scattered light curves from known short-period extrasolar planets. Due to the changing phases of an extrasolar planet as it orbits its parent star, the combined light of the planet-star system will vary on the order of tens of micromagnitudes. The amplitude and shape of the resulting light curve is sensitive to the planet's radius and orbital inclination, as well as the composition and size distribution of the scattering particles in the planet's atmosphere. To predict the capabilities of MOST and other planned space missions, we have constructed a series of models of such light curves, improving upon earlier work by incorporating more realistic details such as: limb darkening of the star, intrinsic granulation noise in the star itself, tidal distortion and back-heating, higher angular resolution of the light scattering from the planet, and exploration of the significance of the angular size of the star as seen from the planet. We use photometric performance simulations of the MOST satellite, with the light curve models as inputs, for one of the mission's primary targets, $\tau$ Boötis. These simulations demonstrate that, even adopting a very conservative signal detection limit of 4.2 $\mu$mag in amplitude (not power), we will be able to either detect the $\tau$ Boötis planet light curve or put severe constraints on possible extrasolar planet atmospheric models.

arXiv commentAccepted to ApJ, 24 pages, 8 figures

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Cited by in corpus (15)

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• The transmission spectrum of Earth-size transiting planets
• MOST detects variability on tau Bootis possibly induced by its planetary companion
• Phase Functions and Light Curves of Wide Separation Extrasolar Giant Planets
• Detection of Planetary Emission from the Exoplanet TrES-2 using Spitzer /IRAC
• Phase light curves for extrasolar Jupiters and Saturns
• Hydrodynamical simulations of convection-related stellar micro-variability. I. Statistical relations for photometric and photocentric variability
• Bright optical dayside emission from extrasolar planet CoRoT-2b
• Planetpol polarimetry of the exoplanet systems 55 Cnc and tau Boo
• Distinguishing Between Stellar and Planetary Companions With Phase Monitoring
• Next Generation of Telescopes or Dynamics Required to Determine if Exo-Moons have Prograde or Retrograde Orbits
• A comparison of spectroscopic methods for detecting starlight scattered by transiting hot Jupiters, with application to Subaru data for HD 209458b and HD 189733b
• Fourier spectra from exoplanets with polar caps and ocean glint