Photometry and geometrical elements of CC Com
Publications of the Astronomical Society of the Pacific
The average color indices (B-V) = + 1™24 and (U-B) = + l ni 02 and short period (F = 0^2207) place this system at the lower temperature end of the period-color relation for the W UMa-type binaries. During minima the indices change to (B-V) = + l'"29 and (U-B) = + UOO; however, the (U-B) index reveals rather large scatter and was also observed to decrease abnormally to ( U-B) = + 0 I!1 93 during one primary minimum. It is unclear whether these abnormal variations in (U-B) are related to an
... related to an ultraviolet excess of about +0.1 (unfortunately no red-leak corrections were applied) although some support for that can be found in the fragmentary uvby photometry. Small night-to-night changes might be present in the V-light curve as well. The large amplitude of light variation (0.85 and 0.75 magnitude in V) and the presence of a total eclipse with semiduration of totality of about 8° permit one to determine the geometrical elements with rather high accuracy, in spite of relatively large photometric errors due to the faintness of the system ( + 11.3 < V < + 12.2). CC Com belongs to the W-type systems, with a relative temperature excess of the secondary component X = 0.051 ± 0.002. Other elements are: i = 90° 0 ± 0°2,q = 0.521 ± 0.004,/= 0.765 ± 0.013 for the assumed T e = 4300° K. The membership of CC Com in the Coma Cluster (Mel 111) is discussed and shown to be very likely, but its acceptance must await further proper-motion studies. The individual times of minimum light of CC Com, and the new ephemeris, are given.