Abstract Details

Name: Anindita Mondal
Affiliation: S N Bose National Centre for Basic Sciences
Conference ID: ASI2017_508
Title : Spectroscopic analysis of slow nova V5558 Sgr during its 2007 outburst using photoionization code CLOUDY
Authors and Co-Authors : Ramkrishna Das, S N Bose National Centre for Basic Sciences. Soumen Mondal, S N Bose National Centre for Basic Sciences
Abstract Type : Poster
Abstract Category : Stars,ISM and the Galaxy
Abstract : Novae are close binary systems consisting of a white dwarf as the primary star and a red-giant or main sequence star as the secondary. They are mainly of two types, classical and recurrent. Study of novae are of utter importance as the ejecta during the outburst takes an important role in the chemical evolution of interstellar medium. We present an spectroscopic analysis of the slow nova V5558 Sgr using published optical and near-infrared(NIR) spectra its during 2007 outburst(Apr. 14.777, 2007). We use optical spectroscopic data on 7 epochs (Apr. 16 & 25, May 8, Oct. 23, Nov. 23, 2007 and Feb. 12 & 27, 2008) taken from Fujii-Bisei Observatory(FBSPEC) and NIR JHK spectroscopic data on 3 epochs (Apr. 26, May 7 & Oct. 20, 2007) taken from Mt. Abu Telescope(NICMOS). We use CLOUDY photoionization code to generate synthetic spectra by varying several parameters. The model generated spectra are then compared with observed emission line spectra obtained at seven epochs. We obtain the best fit model parameters through χ2 minimization technique. Our model results fit well with observed optical and NIR spectra with 1 < χ2_red < 2 . The best-fit model parameters are compatible with a hot white dwarf source with TBB of 1.0 − 6.3 × 10^5 K and high luminosity of Log(L) = 37.0 − 40.0erg s^(−1). The Hydrogen density varies as the nova evolves; Log(n_H) = 12.2 − 8.5 cm^(−3) . From the analysis we find following elemental abundances (by number) with respect to solar: He/He⊙ = 0.1−2.8, N/N⊙ = 4.0 − 200, O/O⊙ = 0.2 − 1.0, Fe/Fe⊙ = 0.1 − 27, Si/Si⊙ = 1.0 − 3.5, Ar/Ar⊙ =1.2 − 1.5 and Ca/Ca⊙ = 1.2 , all other elements were set at the solar abundance. We also identify some Fe and He lines in the NIR J-band using the CLOUDY database. Using the CLOUDY generated spectra, we calculate the distance to the nova to be 1.55 kpc and using the obtained parameter values, we estimate an ejected mass in the range of 0.012 − 7.0 × 10^(−4) M⊙, both support the previously calculated results.