Transiting Exoplanet Monitoring Project (TEMP). IV. Refined System Parameters, Transit Timing Variations and Orbital Stability of the Transiting Planetary System HAT-P-25

TL;DR

This study refines the orbital and physical parameters of exoplanet HAT-P-25b using new light curves, finds no significant transit timing variations, and constrains the masses of potential nearby perturbers.

Contribution

The paper provides updated system parameters for HAT-P-25b and sets new limits on the masses of possible additional planets through TTV analysis.

Findings

No significant TTVs detected at the 80 s level.

Mass limits for nearby perturbers are established at 0.3-0.5 Earth masses.

Long-period perturbers with mass >3000 M_J within 11.2 AU are excluded.

Abstract

We present eight new light curves of the transiting extra-solar planet HAT-P-25b obtained from 2013 to 2016 with three telescopes at two observatories. We use the new light curves, along with recent literature material, to estimate the physical and orbital parameters of the transiting planet. Specifically, we determine the mid-transit times (T$_{C}$) and update the linear ephemeris, T$_{C[0]}$=2456418.80996$\pm$0.00025 [$\mathrm{BJD}_\mathrm{TDB}$] and P=3.65281572$\pm$0.00000095 days. We carry out a search for transit timing variations (TTVs), and find no significant TTV signal at the $\Delta T=$80 s-level, placing a limit on the possible strength of planet-planet interactions ($\mathrm{TTV_{G}}$). In the course of our analysis, we calculate the upper mass-limits of the potential nearby perturbers. Near the 1:2, 2:1, and 3:1 resonances with HAT-P-25b, perturbers with masses greater than 0.5, 0.3, and 0.5 $\mathrm{M_{\oplus}}$ respectively, can be excluded. Furthermore, based on the analysis of TTVs caused by light travel time effect (LTTE) we also eliminate the possibility that a long-period perturber exists with $M_{\rm p}> 3000 \,\mathrm{M_{J}}$ within $a=11.2\,{\rm AU}$ of the parent star.