Keck/HIRES radial velocities for HD 97658

The mid-transit times are 5.6{sigma} earlier than those of the unverified transit-like signals reported in 2011, and we find no connection between the two sets of events. The transit depth together with our determined stellar radius (R_{star}_=0.703_-0.034_^+0.039^R_{sun}_) indicates a 2.34_-0.15_^0.18^R_{Earth}_ super-Earth.

When combined with the radial velocity determined mass of 7.86+/-0.73M_{Earth}_, our radius measure allows us to derive a planet density of 3.44_-0.82_^+0.91^g/cm3. Models suggest that a planet with our measured density has a rocky core that is enveloped in an atmosphere composed of lighter elements. The star of the HD 97658 system is the second brightest known to host a transiting super-Earth, facilitating follow-up studies of this not easily daunted, warm and likely volatile-rich exoplanet.