Radial velocities and BVIc LCs of the EB* CU Cnc

Spectral features, radial velocities, elemental abundance estimates, other spectral data, and BVI_C_ light curves are reported for the double-M dwarf eclipsing binary CU Cancri-a good target for a radius check versus the Zero Age Main Sequence (ZAMS) due to the low component masses and corresponding very slow evolutionary expansion. The estimate of [Fe/H] is about 0.4, although continuum placement and other difficulties due to line crowding introduce the usual uncertainties for red dwarfs.

Detection of the LiI{lambda}6707 line was attempted, with an estimated upper limit of 50m{AA}. Spectral and photometric indicators of stellar activity are described and illustrated. Other objectives were to measure the stellar radii via simultaneous velocity and light-curve solutions of earlier and new data while also improving the ephemeris by filling gaps in timewise coverage with the new velocities and eclipse data from the new light curves.