APOSTLE: Longterm Transit Monitoring and Stability Analysis of XO-2b (The Astrophysical Journal, 2013)

• Eric Agol
• Praveen Kundurthy
• Rory Barnes

Full Citation:
Kundurthy, P., Barnes, R., Becker, A. C., Agol, E., Williams, B. F., Gorelick, N., & Rose, A. (2013). APOSTLE: LONGTERM TRANSIT MONITORING AND STABILITY ANALYSIS OF XO-2b. The Astrophysical Journal, 770(1), 36. https://doi.org/10.1088/0004-637x/770/1/36

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 sstarf), stellar density (ρsstarf), impact parameter (b), and orbital inclination (i orb). Our errors on system parameters like a/R sstarf and ρsstarf 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.

URL:
https://iopscience.iop.org/article/10.1088/0004-637X/770/1/36

VPL Research Tasks:
Task C: The Habitable Planet