APOSTLE: Longterm Transit Monitoring and Stability Analysis of XO-2b
Venue
The Astrophysical Journal, vol. 770 (2013), pp. 36
Publication Year
2013
Authors
Praveen Kundurthy, Rory Barnes, Andrew C Becker, Eric Agol, Benjamin F Williams, Noel Gorelick, Amy Rose
BibTeX
Abstract
The Apache Point Survey of Transit Lightcurves of Exoplanets (APOSTLE) observed 10
transits of XO-2b over a period of 3 yr. We present measurements that confirm
previous estimates of system parameters like the normalized semi-major axis (a/R),
stellar density (ρ), impact parameter (b), and orbital inclination (iorb). Our
errors on system parameters like a/R and ρ have improved by ∼40% compared to
previous best ground-based measurements. Our study of the transit times show no
evidence for transit timing variations (TTVs) and we are able to rule out co-planar
companions with masses 0.20 M⊕ in low order mean motion resonance with XO-2b. We
also explored the stability of the XO-2 system given various orbital configurations
of a hypothetical planet near the 2:1 mean motion resonance. We find that a wide
range of orbits (including Earth-mass perturbers) are both dynamically stable and
produce observable TTVs. We find that up to 51% of our stable simulations show TTVs
that are smaller than the typical transit timing errors (∼20 s) measured for XO-2b,
and hence remain undetectable. Key
