pi Men radial velocity curves

We report on the confirmation and mass determination of {pi} Men c, the first transiting planet discovered by NASA's TESS space mission. {pi} Men is a naked-eye (V=5.65mag), quiet G0 V star that was previously known to host a sub-stellar companion ({pi} Men b) on a longperiod (Porb=2091-days), eccentric (e=0.64) orbit. Using TESS time-series photometry, combined with Gaia data, published UCLES at AAT Doppler measurements, and archival HARPS at ESO-3.6m radial velocities, we found that {pi} Men c is a close-in planet with an orbital period of Porb=6.27-days, a mass of Mc=4.52+/-0.81M_{Earth}_, and a radius of Rc=2.06+/-0.03R_{Earth}_.

Based on the planet's orbital period and size, {pi} Men c is a super-Earth located at, or close to, the radius gap, while its mass and bulk density suggest it may have held on to a significant atmosphere. Because of the brightness of the host star, this system is highly suitable for a wide range of further studies to characterize the planetary atmosphere and dynamical properties. We also performed an asteroseismic analysis of the TESS data and detected a hint of power excess consistent with the seismic values expected for this star, although this result depends on the photometric aperture used to extract the light curve.