Time Development of Recurrent Nova CI Aquilae's 2000 Outburst between 0.8 and 2.5 MICRONS

Abstract

We report 0.8-2.5 m spectrophotometry of CI Aquilae at eight epochs between 2000 May 9 and 2001 June 2 UT, corresponding to approximately 3 and 391 days after peak brightness. Near peak brightness, the spectra showed emission lines that were characteristic of a low-excitation, nitrogen-rich shell. Within a few weeks, the spectra began to show higher excitation/ionization emission lines indicative of a harder illuminating source: the neutral metal lines faded, leaving only lines of H i, He i, and He ii and the emerging coronal lines. A month after peak brightness, the [Ca viii] coronal line at 2.3205 m appeared and persisted until the last of our observations, on day +391. From the O i line ratios, we deduced a reddening of E BÀV = 1.5 AE 0.1 and a visual extinction of A V = 4.6 AE 0.2. Along with the rate of decline from the light curve (t 2 ), we derived a distance of 2.6 AE 1.3 kpc. The frequently observed unidentified novae lines were present in CI Aquilae along with a potentially new member of the group at 2.425 AE 0.002 m.

Spectroscopic observations of the recurrent nova CI Aquilae during the 2000 outburst

“…These results agree with ours within the limits of the errors. On the other hand, Lynch et al (2004) found a higher value E(B − V) = 1.5 ± 0.15 from the ratios of the near-infrared O I lines. The cause of the disagreement with our result is not known.…”

“…Therefore, its distance may be less than or does not exceed much 1 kpc at maximum. Absolute V magnitudes of light maxima higher than −7 mag were derived for the outbursts in 1917 and 2000 from the decline rates of luminosity: those are M V = −7.35 ± 0.2 mag by Kiss et al (2001), M V = −7.4 mag by Burlak & Esipov (2001), and M V = −7.55 ± 0.5 mag by Lynch et al (2004). If we adopt the observed maximum luminosity m V = 9.0 mag (Kiss et al 2001) or m V = 8.8 mag (Burlak & Esipov 2001) for the outburst in 2000, the above derived absolute maximum luminosities give distances larger than 4.5 kpc, adopting A V = 2.9 mag.…”

“…Kiss et al (2001) estimated the magnitude and the epoch of light maximum to have been m V 9 mag at 2000 May 5.0 UT, that is JD 2451669.5. Some slightly different parameters are proposed also, those are m V = 8.8 mag at JD 2451666 by Burlak & Esipov (2001) and m V = 9.2 mag at JD 2451671 by Lynch et al (2004). The parameters of Kiss et al (2001) are used in this paper.…”

“…Lynch et al (2004) performed a detailed analysis for the nearinfrared spectra obtained in 2000 and 2001. In this paper, lowand high-resolution optical spectra obtained in 2000 May, June, and July are presented, which follow the spectral evolution from the early decline stage to the nebular stage. The properties of this object are studied using the spectral data.…”

NOVA V2362 CYGNI (NOVA CYGNI 2006):SPITZER,SWIFT, AND GROUND-BASED SPECTRAL EVOLUTION

“…Table 2 for line identifications in the 0.8-4.5 μm region). The six unidentified lines that frequently appear in novae at 1.1114, 1.1901, 1.5545, 2.0996, and 2.425 μm (Williams et al 1996;Lynch et al 2001Lynch et al , 2004 were not evident. On or immediately after 2006 November 30, dust formed and changed the spectral energy distribution (SED) of the nova shell.…”