A. B. Giles, Astronomy Department, Leicester University, reports that BVIJHK photometry by several teams at the 1.5-m infrared flux collector on Tenerife, together with measurernents already announced or from private communication of unpublished results, provides a data base of up to 30 points per color over 213 days. The observations have been folded at periods in the range 2-50 days, and smooth J, H and K lightcurves result for a period P = 11.80 +/- 0.05 days. Each curve shows a long deep maximum (duration 0.65 P, depth 1.3 mag at H), and the lowest point of the minimum defines the ephemeris 1979 Aug. 14.26 (+/- 0.50) UT + 11.80E, in agreement with the minimum of Kemp and Arbabi (IAUC 3391). A short secondary minimum is probably also present. The maximum radial velocity observed by Crampton et al. (IAUC 3388) on July 4.0 +/- 0.2 UT also occurs at maximum light. The length of the minimum suggests an eccentric orbit, which possibly accounts for the discrepancy with the spectroscopic period of 13.0 +/- 0.1 days reported by Crampton et al. The optical lightcurves appear less smooth than the infrared curves, probably because of the 160-day period of the emission lines.
International Astronomical Union Circular
- Pub Date:
- October 1979