We report the first planet discovery from the two–wheeled Kepler ( K2 ) mission : HIP 116454 b .
The host star HIP 116454 is a bright ( V = 10.1 , K = 8.0 ) K1–dwarf with high proper motion , and a parallax–based distance of 55.2 \pm 5.4 pc .
Based on high-resolution optical spectroscopy , we find that the host star is metal-poor with [ Fe/H ] = -0.16 \pm 0.08 , and has a radius R _ { \star } = 0.716 \pm 0.024 R _ { \odot } and mass M _ { \star } = 0.775 \pm 0.027 M _ { \odot } .
The star was observed by the Kepler spacecraft during its Two-Wheeled Concept Engineering Test in February 2014 .
During the 9 days of observations , K2 observed a single transit event .
Using a new K2 photometric analysis technique we are able to correct small telescope drifts and recover the observed transit at high confidence , corresponding to a planetary radius of R _ { p } = 2.53 \pm 0.18 R _ { \oplus } .
Radial velocity observations with the HARPS-N spectrograph reveal a 11.82 \pm 1.33 M _ { \oplus } planet in a 9.1 day orbit , consistent with the transit depth , duration , and ephemeris .
Follow–up photometric measurements from the MOST satellite confirm the transit observed in the K2 photometry and provide a refined ephemeris , making HIP 116454 b amenable for future follow–up observations of this latest addition to the growing population of transiting super-Earths around nearby , bright stars .