K2-291 ( EPIC 247418783 ) is a solar-type star with a radius of R _ { * } = 0.899 \pm 0.034 R _ { \odot } and mass of M _ { * } = 0.934 \pm 0.038 M _ { \odot } . From the K2 C13 data , we found one super-Earth planet ( R _ { p } = 1.589 ^ { +0.095 } _ { -0.072 } R _ { \oplus } ) transiting this star on a short period orbit ( P = 2.225177 ^ { +6.6 e - 5 } _ { -6.8 e - 5 } days ) . We followed this system up with adaptive-optic imaging and spectroscopy to derive stellar parameters , search for stellar companions , and determine a planet mass . From our 75 radial velocity measurements using HIRES on Keck I and HARPS-N on Telescopio Nazionale Galileo , we constrained the mass of K2-291 b to M _ { p } = 6.49 \pm 1.16 M _ { \oplus } . We found it necessary to model correlated stellar activity radial velocity signals with a Gaussian process ( GP ) in order to more accurately model the effect of stellar noise on our data ; the addition of the GP also improved the precision of this mass measurement . With a bulk density of \rho = 8.84 ^ { +2.50 } _ { -2.03 } g cm ^ { -3 } , the planet is consistent with an Earth-like rock/iron composition and no substantial gaseous envelope . Such an envelope , if it existed in the past , was likely eroded away by photoevaporation during the first billion years of the star ’ s lifetime .