C. Chevalier, Observatoire de Meudon; S. A. Ilovaisky, Centre d'Etudes Nucleaires de Saclay; and H. Mauder, Astronomical Institute, Tubingen University, write: "Photoelectric photometry at the European Southern Observatory reveals a one-week, approximately sinusoidal 15-20 percent modulation in the optical flux. Minima occurred on Mar. 2, 9 and 18. Assuming phase agreement with the x-ray modulation (IAUC 2949), we derive a period of 8.0 +/- 0.2 days, consistent with that from the x-ray data alone but twice that suggested by Duerbeck and Walter (1976, Astron. Astrophys. 48, 141)."
International Astronomical Union Circular
- Pub Date:
- June 1976