Long-lasting super-Eddington luminosity of the classical nova V339 Del with strong dust emission
Authors:
A. Skopal
Image & caption:
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Image caption::
Left: Observed spectrum of the nova V339 Del (in magenta) and its model (black line). The model consists of the radiation from the WD (blue line), nebula (green) and dust (gray). Right: Sketch for nova ejecta. The WD pseudophotosphere is in dark-blue, stellar wind in light-blue, equatorially concentrated outflow with dust in yellow with gray strips and bow shocks as orange lines. The white array represents stopping-down the wind from the WD indicated on day 100 of the nova age.
Description:
The classical nova V339 Delphini was born on August 14, 2013 (= nova age 0) as a result of the explosive thermonuclear fusion on the surface of a white dwarf (WD) after accretion of the critical amount of material from its companion in a binary system. The nova was very bright, well seen by the naked eye around its maximum. Consequently, a large amount of observations has been performed from gamma-rays to the radio wavelengths, followed by a number of excellent studies by experts from all over the world. In this paper, using our original method of multiwavelength modeling the nova spectrum, we revealed new striking results: (i) At the nova age of 35 days, the WD photosphere was oblate in poles and a slow equatorially concentrated mass-outflow contained dust grains. (ii) From day 35 to 72, the nova significantly stopped-down the mass-outflow. (iii) On day 100, the co-existence of the strong dust emission and the luminous high-temperature WD confirmed the disk-like formation around the WD, where the dust can spend a long time. (iv) Our modeling revealed highly super-Eddington luminosity of the burning WD lasting, at least, for the first 100 days of the nova life. This finding represents a new challenge for theoretical modeling of the nova phenomenon.
Reference:
The Astrophysical Journal, 878:28 (18pp), 2019 June 10
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