An ingress and a complete transit of HD 80606 b

TL;DR

This study provides detailed transit observations of HD 80606 b using multiple telescopes, refining system parameters and confirming the planet's size with high precision.

Contribution

It presents the first simultaneous multi-longitude observations of HD 80606 b's transit, improving constraints on its duration, period, and physical characteristics.

Findings

Refined planet radius to 0.921 ± 0.036 RJup

Confirmed transit duration and period with high precision

System parameters consistent with previous studies

Abstract

We have used four telescopes at different longitudes to obtain near-continuous lightcurve coverage of the star HD 80606 as it was transited by its \sim 4-MJup planet. The observations were performed during the predicted transit windows around the 25th of October 2008 and the 14th of February 2009. Our data set is unique in that it simultaneously constrains the duration of the transit and the planet's period. Our Markov-Chain Monte Carlo analysis of the light curves, combined with constraints from radial-velocity data, yields system parameters consistent with previously reported values. We find a planet-to-star radius ratio marginally smaller than previously reported, corresponding to a planet radius of Rp = 0.921 \pm 0.036RJup .