V2540 Oph: Nova Oph 2002

Left: Discovery Image by K. Haseda. Right: Light Curve of V2540 Oph

The discovery of a nova by K. Haseda was reported on January 26 (vsnet-campaign-news 125, vsnet-campaign-nova 772). The object had already been bright on January 19 as shown by a T. Seki's prediscovery observation (vsnet-campaign-nova 777, 785). D. West confirmed the object of V=9.19 and Rc=8.67 on January 26 (vsnet-campaign-nova 774, 776) and reported the detection of a H_alpha emission line, which confirmed the nova nature of this new object (vsnet-campaign-nova 775, vsnet-campaign-news 126). Independent discovery was reported by Y. Nakamura on January 27 (vsnet-campaign-nova 778, 781). A. Retter performed spectroscopy and reported that the object is very likely a classical nova that belongs to the Fe II class, caught at the early decline phase (vsnet-campaign-nova 786, vsnet-campaign-news 127). This nova was given the permanent GCVS designation of V2540 Oph in IAUC 7810 (vsnet-campaign-nova 801).

The fading rate was reported to be relatively slow in the end of Janaury (vsnet-campaign-nova 799), and then, a brightening was detected on January 30 (vsnet-campaign-nova 802, 808). It then remained at about 8.6mag until February 1 (vsnet-campaign-nova 813, 817), and then again started gradual fading (vsnet-campaign-nova 818, 819). The object again experienced a new brightening to 8th mag on February 11 (vsnet-campaign-nova 828). The bright state continued until February 14 (vsnet-campaign-nova 832, 833, 834, 836), and then, the object started relatively rapid fading on February 15. After that, the object again brightened to 9.6mag as reported by E. Muyllaert on February 21. These repetitive brightenings indicates that this nova is a highly oscillating one. Some other brightenings were also reported (vsnet-campaign-nova 846, 847). A brightening to 9.9mag was reported on March 4 by B. Tregaskis (vsnet-campaign-nova 862), and it was confirmed on March 6 at 9.5mag by A. Pearce (vsnet-campaign-nova 869). The object further brightened to 8.9mag on March 7 (vsnet-campaign-nova 870). It again began fading on March 10-11 (vsnet-campaign-nova 875). O. Pejcha reported the next brightening from V=9.62 on March 30 to V=8.96 on March 31 (vsnet-campaign-nova 893, 894, 898). After temporary fading fron this brightening, it re-brightened to 8.4mag on April 7 (vsnet-campaign-nova 900). A fading from the oscillation peak was observed around April 15-18 (vsnet-campaign-nova 926). After this large brightening, the oscillations was likely less prominent (vsnet-campaign-nova 934). On May 17, a relatively large-amplitude brightening (to 8.9mag) was reported (vsnet-campaign-nova 935). A possible minor brightening was reported on June 8 (vsnet-campaign-nova 937).

This nova entered a relatively smooth fading phase from July (vsnet-campaign-nova 939). The fading rate possibly increased (vsnet-campaign-nova 941).

A. Retter reported that they detected periodic modulations with the best period of ~2.4 h. He proposed that this period could be the binary orbital period. It would be then in the period gap of cataclysmic variables. He further reported that the nova would be an intermediate polar supporting the possible connection between the transition phase in novae and intermediate polars if other periods are confirmed. T. Kato commented that the transition phase oscillations of novae now seem to be better understood as a natural consequence of an instability in the super-Eddington winds (vsnet-campaign-nova 943, 944, 946, 947, 948, 949, 950, 952, 953, 954, 957, 958, 959, 960, 961, 962). D. West performed time-series photometry on July 31 and reported no periodic modulations were detected (vsnet-campaign-nova 945). His observations on August 1 show 0.031, 0.043, and 0.07 day periodicities (vsnet-campaign-nova 955, 951). D. West reported some V and Rc observations in [vsnet-campaign-nova 971], which showed that the object slowly continued to fade and become "redder".

Other articles:
vsnet-campaign-nova 780, 782, 790, 795, 824, 838, 841, 842, 843, 850, 851, 872, 874, 887, 888, 936, 940, 942, 1080

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