V382 Vel (Nova Velorum 1999)
V382 Vel (Nova Vel 1999) was the brightest nova outburst seen since V1500 Cyg (Nova Cyg 1975). Not surprisingly, it was also relatively close by, at an estimated 1.7-2.5 kpc (Balman, Retter and Bos 2006). Reaching a magnitude of 2.5 on May 22, 1999, it was discovered independently by Peter Williams and Alan C. Gilmore about a day earlier and a half magnitude fainter. Its peak absolute magnitude is estimated to be a bright -8.9; this suggests its system contains a relatively high mass white dwarf (about 1.15 solar masses) of the O-Ne-Mg type. This is consistent with the spectrum of the nova outburst, which has been classified as a "neon" or O-Ne type (Della Valle et al. 2002). Due to the nova’s high apparent brightness the evolution of its light curve and spectrum could be followed well into the decay process (Augusto and Diaz 2003). The result is that Nova Vel 1999 has been dubbed "one of the best examples of a prototypical fast nova" (Della Valle et al. 2002: 165).
The nova is now below magnitude 14.0. Due to its southern declination, there have only been 1,798 observations submitted to the AAVSO. However, AAVSO photometric data from 1999 to 2003 was cited by Balman, Retter, and Bos in their 2006 paper. This group found a 3.5 hour orbital period for the system; in addition, close examination of fluctuations in the light curve over time suggest that renewed mass transfer may be triggered by x-rays produced by the nova outburst irradiating the secondary star. This could re-establish the accretion disk, and eventually lead to another nova outburst in the future. Therefore this system allowed astronomers to not only test their theories of the evolution of a white dwarf binary system, but predict what effects could be noted in the light curves of future bright novae (ones whose evolution can be followed long after the maximum brightness is observed).
The current Past President of the AAVSO Jaime Garcia presented a paper at the Spring 1999 AAVSO meeting summarizing 591 observations of the nova by the variable star observing sections of the Latin American Astronomical League and the Brazilian Observational Network REA.
V 382 Vel became an even more important astronomical object over a decade after its outburst, with the discovery of Nova Monocerotis 2012. Nova Mon 2012 is noted for being the first classical nova to be discovered with very short wavelength instruments prior to its optical outburst (Shore et al. 2013). It was first seen in gamma ray data in late June 2012, more than a month before the first optical signature of an outburst was noted (because the position of the sun made optical observations impossible at that time). Steven Shore and his colleagues followed the evolution of this unique object using both optical and ultraviolet spectroscopy and compared these results to their earlier work on V 382 Vel (Shore et al. 2003). It was determined that these two objects, along with fellow O-Ne novae V1974 Cyg and QU Vul, form a subclass with well-defined characteristics that may allow for their future use as a standard candles (Shore et al. 2013). Therefore V382 not only demonstrates the importance of Southern Hemisphere variable star observers to the mission of the AAVSO and the astronomical community, but illustrates the fact that each nova has the possibility of providing valuable information that enhances our greater understanding of stars in particular, and the universe at large.
- Augusto, A. and Diaz, M.P. (2003) The Spectral evolution of V382 Velorum (Nova Vela 1999). AJ125: 3349-3358.
- Balmann, S., Retter, A., and Bos, M. (2006) The Detection of a 3.5 hr Period in the Classical Nova Velorum 1999 (V382) and the The Long-term behavior of the Nova Light Curve. AJ 131: 2628-2633.
- Della Valle, M. et al. (2002) The Evolution of Nova V382 Velorum 1999. Astron. Astroph.390: 155-166.
- Garcia, J.R. (2000) Nova Velorum 1999 (V382 Vel) From South America. JAAVSO 29: 19-25.
Shore, S.N. et al. (2003) The Early Ultraviolet Evolution of the ONeMg Nova V 38
2 Velorum 1999. AJ 125: 1507-1518.
- Shore, S.N. et al. (2013) The Spectroscopic Evolution of the γ-ray Emitting Classical Nova Nova Mon 2012. A & A 553: A123.