V1280 Scorpii: Ir Spectral Evolution From 4 Feb 2007 To 4 Oct 2008
Abstract
We report a time series of IR spectra (0.8 - 2.5 µm) of V1280 Scorpii that shows the spectral evolution of the object including dust formation and partial dust clearing. This unusual nova formed dust during early decline, only a couple of weeks after peak brightness, and therefore t2 and t3 are difficult to interpret. The visible brightness has increased monotonically ever since dust formation and is presently around mV = 10, only 4 magnitudes below peak brightness.
The spectra reveal a very slow development; 20 months after peak brightness the spectrum is still indicative of a very low excitation spectrum: HI, He I, Fe II and Lyman-beta-fluoresced OI still dominate the spectrum. The lines are narrow ( 300 km/s FWHM) though they also show a weak, broader component (2000 km/s FWHM). Even as late as 20 months after outburst many lines show P-cygni profiles, a probable indication that a strong wind continues to blow. Such a wind would also help explain the relatively high brightness of the object this long after peak brightness. Thermal emission from the dust is present and is weakening with time. This suggests that the expanding dust shell is thinning out and progressively exposing the stellar system to our line-of-sight. This work supported in part by The Aerospace Corporation's Independent Research and Development Program. Observations were carried out at the Infrared Telescope Facility (IRTF) and at Lick Observatory.- Publication:
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American Astronomical Society Meeting Abstracts #214
- Pub Date:
- May 2009
- Bibcode:
- 2009AAS...21442808L