The classical novae are manifestations of thermonuclear explosions on the surface of a white dwarf (WD) accreting hydrogen in a close binary system. The classical novae are highly dynamic phenomena, with timescales ranging from minutes to years.
Novae are marked by an extraordinary spectral evolution. In the initial phases one sees an optically thick, expanding photosphere. Later, in some cases, one sees the development of inverse P Cygni absorption lines from the cool, high velocity ejecta. As the photosphere becomes optically thin, emission lines of the Hydrogen Balmer series and, often, Fe II, strengthen. The emision line profiles evolve, as do the line ratios, as the optical depth of the ejecta decreases, and the nova moves from the nebular to the auroral phase.
Classical novae exhibit an almost bewildering variety of behaviors. Payne-Gaposchkin (1957) described the evolution of novae, as they were known at the time. Williams (1992) discussed the formation of the lines, and divided novae into the classes of Fe II novae and the He-Ne novae. Novae are also categorized as recurrent and classical novae, with the former having more than one recorded outburst. Over a long enough baseline, it is likely that all novae are recurrent.
Spectroscopic observations of novae have rarely been done uniformly, mostly because of telescope scheduling constraints. The availability of the SMARTS telescopes makes possible routine photometric and spectroscopic monitoring programs of time-variable sources. Hence we have taken this opportunity to study the spectral evolution of novae, with in some cases a denser time-sampling that has ever been attempted.
This work, The STONY BROOK / SMARTS (mostly) Spectroscopic Atlas of (mostly) Southern Novae presents spectra and, in some cases, photometry of the novae we have observed with SMARTS since August 2003. Most of the novae are recent, discovered since 2004. Most are in the southern hemisphere. The observing cadences are irregular; we have concentrated on spectroscopy rather than photometry, on recurrent novae, and on novae that otherwise show unusual characteristics.
This atlas focuses on spectroscopy. While amateur astronomy instrumentation
has become very impressive lately, and a number of spectra of the brighter
novae have been taken and distributed, we go considerably deeper, with higher
We do not have the observing time necessary to undertake as full a photometric
program. We cannot compete with the density of photometric observations of
amateur nova hunters, although we have the advantage of routinely obtaining
Large amounts of data can be overwhelming. One purpose of this atlas is to make the data accessible to the community. Astrophysical analysis of the spectra is beyond the scope of the atlas. The references are mostly of publications containing early raw optical data, including IAU Circulars and Telegrams, and are not intended to be complete.
We envision this as a living atlas. So long as we continue this observing project, we will continue to update the atlas.
Payne-Gaposchkin, C. 1957, (North-Holland, Amsterdam)
Williams, R.E. 1992, AJ, 104, 725