The Qatar-2 transiting exoplanet system was recently observed by the Kepler as part of K2 Campaign 6 in short-cadence mode . We identify dozens of starspot-crossing events , when the planet eclipsed a relatively dark region of the stellar photosphere . The observed patterns of these events demonstrate that the planet always transits over the same range of stellar latitudes , and therefore that the stellar obliquity is less than about 10 ^ { \circ } . We support this conclusion with two different modeling approaches : one based on explicit identification and timing of the events , and the other based on fitting the light curves with a spotted-star model . We refine the transit parameters and measure the stellar rotation period ( 18.5 \pm 1.9 days ) , corresponding to a ’ gyrochronological ’ age of 1.4 \pm 0.3 Gyr . Coherent flux variations with the same period as the transits are well modeled as the combined effects of ellipsoidal light variations ( 15.4 \pm 4.8 ppm ) and Doppler boosting ( 14.6 \pm 5.1 ppm ) . The magnitudes of these effects correspond to a planetary mass of 2.6 \pm 0.9 ~ { } M _ { \text { Jup } } and 3.9 \pm 1.5 ~ { } M _ { \text { Jup } } , respectively . Both of these independent mass estimates agree with the mass determined by the spectroscopic Doppler technique ( 2.487 \pm 0.086 ~ { } M _ { \text { Jup } } ) . No occultations are detected , giving a 2 \sigma upper limit of 0.06 on the planet ’ s visual geometric albedo . We find no evidence for orbital decay , although we are only able to place a weak lower bound on the relevant tidal quality factor : Q ^ { \prime } _ { \star } > 1.5 \times 10 ^ { 4 } ( 95 % confidence ) .