Nagashima, Masayoshi; Arai, Akira; Kajikawa, Tomoyo; Kawakita Hideyo; Kitao, Eiji; Arasaki, Takayuki; Taguchi, Gaku; Ikeda, Yuji
Novae are generally considered to be "hot" astronomical objects which show effective temperatures of 10,000 K or higher at their visual maximum. However, theoretical predictions suggest that the outer envelope of the nova outflow can become cool enough to form molecules which would be dissociated at such high temperatures. We detected strong C2
and CN absorption bands in the optical spectrum of the nova V2676 Oph, a very slow nova with dust formation. This is the first report of the detection of C2
, and the second of CN, in novae during an outburst. Although, based on previous studies, such simple molecules are predicted form in the envelope of the outflow, there are few reports of their detection thus far. The presence of the molecular envelope is considered to be very transient, with a duration of only a few days, in the case of V2676 Oph.