Transit Monitoring in the South (TraMoS) project: Discarding Transit Timing Variations in WASP-5b

TL;DR

This study monitored nine new transits of WASP-5b, combined them with existing data, and found no significant transit timing variations, constraining the presence of additional planets and supporting certain formation theories.

Contribution

It provides the first comprehensive TTV analysis of WASP-5b with new and existing data, setting tighter limits on potential planetary companions.

Findings

No TTV RMS variations larger than 1 min over 3 years

Discards planets >5, 1, 2 M_earth near specific resonances

No variations in orbital inclination or transit depth

Abstract

We report nine new transit epochs of the extrasolar planet, observed in the Bessell-I band with SOAR at the Cerro Pachon Observatory and with the SMARTS 1-m Telescope at CTIO, between August 2008 and October 2009. The new transits have been combined with all previously published transit data for this planet to provide a new Transit Timing Variations (TTVs) analysis of its orbit. We find no evidence of TTVs RMS variations larger than 1 min over a 3 year time span. This result discards the presence of planets more massive than about 5 M_earth, 1 M_earth and 2 M_earth around the 1:2, 5:3 and 2:1 orbital resonances. These new detection limits exceed by ~5-30 times the limits imposed by current radial velocity observations in the Mean Motion Resonances of this system. Our search for the variation of other parameters, such as orbital inclination and transit depth also yields negative results over the total time span of the transit observations. This result supports formation theories that predict a paucity of planetary companions to Hot Jupiters.