Exoplanetary Transit Constraints Based Upon Secondary Eclipse Observations

TL;DR

This paper derives analytical expressions for the probability of observing secondary eclipses in transiting exoplanets, explores their implications for primary transit constraints, and applies these methods to known exoplanets to aid observational strategies.

Contribution

It provides new analytical tools for assessing secondary eclipse probabilities and their impact on primary transit observability in exoplanet studies.

Findings

Derived analytical expressions for secondary eclipse probabilities.

Quantified how secondary eclipse observations constrain primary transit likelihood.

Applied methods to known exoplanets to guide observational campaigns.

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.