We report on an unprecedented infrared time series of spectra of V1187 Sco, a very fast ONeMg nova. The observations covered a 56 day period ( 2004 August 6 - September 30) starting 2 days after the nova's peak brightness. Time evolution of the spectra revealed changing line strengths and profiles on timescales of less than a day to weeks as the nova evolved from early postmaximum to early coronal phases. When our ground-based optical and Spitzer Space Telescope data were combined, the wavelength coverage of 0.38-36 mu m allowed an accurate spectral energy distribution to be derived when it was about 6 weeks after outburst. Developing double structure in the He I lines showed them changing from narrow to broad in only a few days. Using the O I lines in combination with the optical spectra, we derived a reddening of E( B - V) 1: 56 +/- 0: 08 and a distance of 4: 9 +/- 0: 5 kpc. Modeling of the ejected material strongly suggested that it was geometrically thick with Delta R/R = 0.8-0.9 ( more of a wind than a shell) and a low filling factor of order a few percent. The line shapes were consistent with a cylindrical jet, bipolar, or spherical Hubble flow expansion with a maximum speed of about - 3000 km s(-1). The central peak appeared to be more associated with the spherical component, while the two peaks ( especially in H beta) suggested a ring with either a lower velocity component or with its axis inclined to the line of sight.
Early infrared spectral development of V1187 scorpii (Nova Scorpii 2004 No. 2)
SHORE, STEVEN NEIL;
2006-01-01
Abstract
We report on an unprecedented infrared time series of spectra of V1187 Sco, a very fast ONeMg nova. The observations covered a 56 day period ( 2004 August 6 - September 30) starting 2 days after the nova's peak brightness. Time evolution of the spectra revealed changing line strengths and profiles on timescales of less than a day to weeks as the nova evolved from early postmaximum to early coronal phases. When our ground-based optical and Spitzer Space Telescope data were combined, the wavelength coverage of 0.38-36 mu m allowed an accurate spectral energy distribution to be derived when it was about 6 weeks after outburst. Developing double structure in the He I lines showed them changing from narrow to broad in only a few days. Using the O I lines in combination with the optical spectra, we derived a reddening of E( B - V) 1: 56 +/- 0: 08 and a distance of 4: 9 +/- 0: 5 kpc. Modeling of the ejected material strongly suggested that it was geometrically thick with Delta R/R = 0.8-0.9 ( more of a wind than a shell) and a low filling factor of order a few percent. The line shapes were consistent with a cylindrical jet, bipolar, or spherical Hubble flow expansion with a maximum speed of about - 3000 km s(-1). The central peak appeared to be more associated with the spherical component, while the two peaks ( especially in H beta) suggested a ring with either a lower velocity component or with its axis inclined to the line of sight.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
