Exoplanetary Transit Constraints Based Upon Secondary Eclipse Observations

Abstract

Transiting extrasolar planets provide an opportunity to study the mass-radius relation of planets as well as their internal structure. The existence of a secondary eclipse enables further study of the thermal properties of the the planet by observing at infrared wavelengths. The probability of an observable secondary eclipse depends upon the orbital parameters of the planet, particularly eccentricity and argument of periastron. Here we provide analytical expressions for these probabilities, investigate their properties, and calculate their values for the known extrasolar planets. We furthermore quantitatively discuss constraints on existence and observability of primary transits if a secondary eclipse is observed. Finally, we calculate the a-posteriori transit probabilities of the known extrasolar planets, and we present several case studies in which orbital constraints resulting from the presence of a secondary eclipse may be applied in observing campaigns.Comment: 7 pages, 5 figures, 1 table; accepted for publication in PAS