SIMBAD references

T. Ak, Istanbul University; A. Retter, Pennsylvania State University; and A. Liu, Exmouth, W. Australia, report that unfiltered CCD photometric observations were made of V2540 Oph using a 0.3-m telescope at Exmouth over 26 nights between May 2003 and June 2004. The analysis suggests a periodic signal with an amplitude of about 0.02 mag. The ephemeris is T_min = HJD 2453151.3098 (± 0.0062) + 0.284750 (± 0.000008)E. The periodicity very likely represents the binary period.