Unusual 2001 periastron passage in the colliding-wind binary WR 140 (WC7pd+O4-5)

Sergey V. Marchenko, Anthony F.J. Moffat, Kiril P. Panov, Wilhelm Seggewiss, Victor G. Zubko
2003 Symposium - International astronomical union  
The massive, long-period and highly-eccentric (P= 2899 d,e= 0.88), colliding-wind binary WR 140 (WC7pd+O4-5) may be regarded as a clock-work for its predictable, repeatable IR outbursts related to dust formation right after each periastron passage. However, the 2001 periastron passage broke this monotonic trend. OurUBVphotometry, completely covering the past nine years, shows a series of quasi-regular fadings starting ~ 2 months after periastron passage (Φ ≃ 0.02-0.05). Preliminary analysis
more » ... minary analysis points to dust as a probable cause of the eclipse-like behavior of the system, while the oscillating pattern hints towards instabilities in the wind-wind collision zone. At the same time, contemporaneous spectroscopy shows nothing unusual aside of the strong, but short-lived signs of wind-wind interaction (Φ ≃ 0.99-1.02).
doi:10.1017/s0074180900212060 fatcat:n75sqsgz7bcm3itlojucff77ay