  Spectroscopy of transiting exoplanets can be used to investigate their
atmospheric properties and habitability. Combining radial velocity (RV) and
transit data provides additional information on exoplanet physical properties.
We detect a transiting rocky planet with an orbital period of 1.467 days around
the nearby red dwarf star Gliese 486. The planet Gliese 486 b is 2.81 Earth
masses and 1.31 Earth radii, with uncertainties of 5%, as determined from RV
data and photometric light curves. The host star is at a distance of ~8.1
parsecs, has a J-band magnitude of ~7.2, and is observable from both
hemispheres of Earth. On the basis of these properties and the planet's short
orbital period and high equilibrium temperature, we show that this terrestrial
planet is suitable for emission and transit spectroscopy.
