Detection of orbital parameter changes in the TrES-2 exoplanet ?

TL;DR

This paper reports a potential change in the orbital parameters of the TrES-2 exoplanet, evidenced by a shorter transit duration observed in 2008 compared to 2006, suggesting possible orbital inclination variation.

Contribution

The study provides the first observational evidence of a change in the orbital inclination of TrES-2 over two years, using new photometric data and re-analysis of previous observations.

Findings

Transit duration shortened by ~3.16 minutes since 2006

Change unlikely due to limb darkening effects

Orbital inclination change is the most plausible explanation

Abstract

We report a possible change in the orbit parameters of the TrES-2 exoplanet. With a period of 2.470621 days, the TrES-2 exoplanet exhibits almost "grazing" transits 110.4 minutes duration as measured in 2006 by Holman and collaborators. We observed two transits of TrES-2 in 2008 using the 1.2m Oskar-Luhning telescope (OLT) of Hamburg observatory employing CCD photometry in an i-band and a near to R-band filter. A careful light curve analysis including a re-analysis of the 2006 observations shows that the current transit duration has shortened since 2006 by ~ 3.16 minutes. Although the new observations were taken in a different filter we argue that the observed change in transit duration time cannot be attributed to the treatment of limb darkening. If we assume the stellar and planetary radii to be constant, a change in orbit inclination is the most likely cause of this change in transit duration.