On the Apparent Orbital Inclination Change of the Extrasolar Transiting Planet TrES-2b
Abstract
On June 15, 2009 UT the transit of TrES-2b was detected using the University of Arizona's 1.55 meter Kuiper Telescope with 2.0-2.5 millimag RMS accuracy in the I-band. We find a central transit time of Tc = 2454997.76286 0.00035 HJD, an orbital period of P = 2.4706127 0.0000009 days, and an inclination angle of i = 83.92 0.05, which is consistent with our re-fit of the original I-band light curve of O'Donovan et al. (2006) where we find i = 83.84 0.05. We calculate an insignificant inclination change of i = -0.08 0.07 over the last 3 years, and as such, our observations rule out, at the 11 σ level, the apparent change of orbital inclination to ipredicted = 83.35 0.1 as predicted by Mislis and Schmitt (2009) and Mislis et al. (2010) for our epoch. Moreover, our analysis of a recently published Kepler Space Telescope light curve (Gilliland et al. 2010) for TrES-2b finds an inclination of i = 83.91 0.03 for a similar epoch. These Kepler results definitively rule out change in i as a function of time. Indeed, we detect no significant changes in any of the orbital parameters of TrES-2b.