ON THE APPARENT ORBITAL INCLINATION CHANGE OF THE EXTRASOLAR TRANSITING PLANET TrES-2b

On 2009 June 15 UT the transit of TrES-2b was detected using the University of Arizona's 1.55 m Kuiper Telescope with 2.0–2.5 millimag rms accuracy in the I band. We find a central transit time of T c = 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. where we find i = 83 84 ± 0°.05. We calculate an insignificant inclination change of Δ i = −0 08 ± 0°.07 over the last three years, and as such, our observations rule out, at the ∼11σ level, the apparent change of orbital inclination to i predicted = 83 35 ± 0°.1 as predicted by Mislis & Schmitt and Mislis et al. for our epoch. Moreover, our analysis of a recently published Kepler Space Telescope light curve 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.