TrES-5, a massive hot Jupiter that transits the star GSC 03949-00967 every 1.48 days. From the spectroscopy of the star an effective stellar temperature of 5,171 +/- 36 K is estimated, and photometry of the high-precision transit B, R and I we limit the relationship between the semi-major axis and the radius of the star to be 6.07 +/- 0.14.

We compared these values to model stellar isochrones to obtain a stellar mass of 0.893 +/- 0.024 solar masses. Based on this estimate and the photometric time series, a restriction of the radius of the star to be 0.866 +/- 0.013 solar radii, and the radius of the planet to be 1.209 +/- 0.021 radii of Jupiter. We modeled our radial velocity data assuming a circular orbit and found a planetary mass of 1.778 +/- 0.063 times that of Jupiter.

TrES-5 orbits one of the faintest stars with transiting planets found to date from Earth and demonstrates that precise photometry and tracking spectroscopy is possible, even if it is difficult, even for these types of faint stars.

Observations of TrES-5b

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