  We report the discovery and characterization of an eclipsing M5V dwarf star,
orbiting a slightly evolved F7V main sequence star.
  In contrast to previous claims in the literature, we confirm that the system
does not belong to the galactic open cluster Ruprecht 147. We determine its
fundamental parameters combining K2 time-series data with spectroscopic
observations from the McDonald Observatory, FIES@NOT, and HIRES@KECK. The very
precise photometric data from the K2 mission allows us to measure variations
caused by the beaming effect (relativistic doppler boosting), ellipsoidal
variation, reflection, and the secondary eclipse. We determined the radial
velocity using spectroscopic observations and compare it to the radial velocity
determined from the beaming effect observed in the photometric data. The M5V
star has a radius of $0.200 \substack{+0.007 \\ -0.008}$ $R_{\odot}$ and a mass
of $0.187 \substack{+0.012 \\ -0.013}$ $M_{\odot}$. The primary star has radius
of $1.518 \substack{+0.038 \\ -0.049}$ $R_{\odot}$ and a mass of $1.008
\substack{+0.081 \\ -0.097}$ $M_{\odot}$. The orbital period is $ 5.441995 \pm
0.000007$ days. The system is one of the few eclipsing systems with observed
beaming effect and spectroscopic radial velocity measurements and it can be
used as test case for the modelling of the beaming effect.
  Current and forthcoming space missions such as TESS and PLATO might benefit
of the analysis of the beaming effect to estimate the mass of transiting
companions without the need for radial velocity follow up observations,
provided that the systematic sources of noise affecting this method are well
understood.
