The recurrent nova RS Oph went in outburst for the first time since 1985.
The outburst has been discovered by the Japanese observers Kiyotaka Kanai (Gunma,Isezaki-shi) and Hiroaki Narumi
(Ehime,Kita-gun) and was reported on the VSNet-Alert mailing list. H. Narumi estimated the brightness on
Feb. 12.829 UT at magnitude 4.5 and K. Kanai somewhat later at magnitude 4.6.
The previous outburst dates back from 28th Januari 1985 when RS Oph reached a maximum magnitude of 5.4.
The recurrence time (time interval between outbursts) differs a lot from one outburst to the other. Other outbursts
have been observed in 1898, 1933, 1958, 1967 and 1985. The behavior during the outbursts is surprisingly similar in
Typically RS Oph brightens from minimum (around magnitude 11.5) to maximum in less than 24 hours. The star fades in
3 stages, during the first ~40 days the star fades at about 0.1 magnitudes per day, followed by a slower decline
at about 0.02 mag/day during 40 a 50 days. During the last stage the star fades again more quickly at about 0.05
mag/day. The duration of the complete outburst takes about 100 - 120 days. During quiescence the star displays
variations with an amplitude of 1 to 3 magnitudes.
Only 2 observations of the 1985 outburst could be reported by Frans Van Loo to the VVS WVS.
Hopefully this time more VVS WVS observers will be able to observe this interesting object.
Please use the most recent AAVSO charts to make your observations. The charts are available
More information on RS Oph:
AAVSO VSOTM May 2000
AAVSO Alert Notice 335