Near-infrared studies of V1280 Sco (Nova Scorpii 2007)

Abstract

We present spectroscopic and photometric results of Nova V1280 Sco which were discovered in outburst in early 2007 February. The large number of spectra obtained of the object leads to one of the most extensive, near-infrared spectral studies of a classical nova. The spectra evolve from a P-Cygni phase to an emission-line phase and at a later stage is dominated by emission from the dust that formed in this nova. A detailed model is computed to identify and study characteristics of the spectral lines. Inferences from the model address the vexing question of which novae have the ability to form dust. It is demonstrated, and strikingly corroborated with observations, that the presence of lines in the early spectra of low-ionization species like Na and Mg -indicative of low-temperature conditions -appears to be reliable indicators that dust will form in the ejecta. It is theoretically expected that mass loss during a nova outburst is a sustained process. Spectroscopic evidence for such a sustained mass loss, obtained by tracing the evolution of a P-Cygni feature in the Brackett γ line, is presented here allowing a lower limit of 25-27 d to be set for the mass-loss duration. Photometric data recording the novas extended 12 d climb to peak brightness after discovery are used to establish an early fireball expansion and also show that the ejection began well before maximum brightness. The JHK light curves indicate the nova had a fairly strong second outburst ∼100 d after the first.

The hybrid, coronal lines nova V5588 Sgr (2011 N.2) and its six repeating secondary maxima

“…Most prominent among these CI lines are the 1.165, 1.175 µm region features in the J band and the strong cluster of lines beyond Br10 in the H band in the 1.74 to 1.80 µm region. Examples of these CI lines can be seen in the spectra of several FeII type novae viz., V1280 Sco and V2615 Oph (Das et al 2008;), V2274 Cyg (Rudy et al 2003), V1419 Aql (Lynch et al 1995) and V5579 Sgr (Raj, Ashok & Banerjee 2011). Earlier near-IR spectra, obtained around primary maximum, would have been highly valuable to check if the FeII type characterizing optical wavelengths at that time was similarly dominating the near-IR.…”

Nova Ophiuchus 2017 as a Probe of 13C Nucleosynthesis and Carbon Monoxide Formation and Destruction in Classical Novae

“…This automatically implies that strong neutral Na I emission must originate from relatively cool zones, close to the temperature of ∼1800 K, where the first dust condensates (carbon) are expected to form. These Na lines were thus proposed (Das et al 2008) to be harbingers of imminent dust production in novae and observations of several dust forming novae have established this to be true. CO has a dissociation energy D(CO)=11.1 eV, much larger than the first IP of Na I.…”

Spectral Evolution of Novae in the Near-Infrared Based on Akari Observations

“…V1280 Sco is classified as a FeII nova from its early optical spectrum (Munari et al, 2007) and, thus, is expected to be caused by an explosion on a CO white dwarf. The onset of dust formation around the V1280Sco was reported on 23 days after the discovery (Das et al, 2008;Rudy et al, 2007). These characteristics are consistent with a classification of V1280Sco as a CO nova (Das et al, 2008).…”

“…The onset of dust formation around the V1280Sco was reported on 23 days after the discovery (Das et al, 2008;Rudy et al, 2007). These characteristics are consistent with a classification of V1280Sco as a CO nova (Das et al, 2008). Near-infrared (2.55-4.9µm) spectrum of V1280Sco was taken with AKARI/IRC on 2009 September 8 (940 days after the discovery).…”