The “missing link”: A 4-day period transiting exoplanet around OGLE-TR-111

We report the discovery of a transiting hot Jupiter around OGLE-TR-111, from our radial velocity follow-up of OGLE transiting candidates in Carina. The planet has a mass of $0.53 \pm 0.11$ MJ and a radius of $1.0^{+0.13}_{-0.06}$ RJ. Three transiting exoplanets have already been found among OGLE candidates, all with periods near 1.5 days. The planet presented here, with $P=4.0$ days, is the first exoplanet detected by transits with the characteristics of a “normal” hot Jupiter, as found in abundance by radial velocity surveys. The radius of OGLE-TR-111b and the scarcity of hot Jupiters detected among OGLE transit candidates tend to indicate that the case of HD 209458b, with a radius of 1.4 RJ, is exceptional, with most hot Jupiters being smaller.