Work

Evolution of V339 Del (Nova Del 2013) since 0.37 – 75 Days after Discovery

Year: 2018

Type: conference-paper

Abstract: We study the evolution of V339 Del (Nova Del 2013) during 0.37-75 days after discovery. Spectra from the Liverpool Telescope were collected and analysed to find velocity of ejecta ( v ej ), relative flux of radiance with respect to continuum level and FWHM of the radiation. The evolution of light curve was explained by adopting an ideal nova light curve as criteria. We found that the evolution of V339 Del during t = 0.37 – 75 days can be explained in 7 phases: 1) Initial rise ( t = 0 - 0.6 days); nova is suddenly brighter from V ∼ 11 to ∼6.4. A maximum v eJ is ∼ 2400 km/s. and FWHM first increases and then decreases where this joint ( t = 0.35 days) turns out to be the first detection of X-ray. 2) Pre-maximum halt ( t = 0.6–1.2 days); There is a halt of brightness around V ∼ 5.1–5.9, decreasing v ej , increasing with decreasing FWHM. 3) Final rise (t = 1.2-1.5 days); Nova is brighter again to maximum. The variation of v eJ and radiation have similar trend to the halt phase. 4) Maximum ( t = 1.5–2.5 days); Nova has maximum brightness of V = 4.45 ± 0.01 ( t = 1.67 days) decreasing v eJ and increasing until maximum value and the decreasing afterward, while FWHM decreases from the final rise. 5) Early decline ( t = 2.5 – 35 days); Nova has a drop in brightness and v eJ . The last measurement of v eJ is ∼ 1100–1200 km/s at t = 35.5 days. The radiation seems to have 2 distinct phases in this early decline including: First stage ( t = 2.2∼12 days) where and FWHM increase and nebular spectra begins around t ∼ 10 days. In this stage the nova shell expands optical depth reduces, marking pseudo-photosphere shrink. Second stage ( t = 12∼35 days) where and FWHM decrease and SED shift to near-IR until not visible in optical ( t = 28 days). Iron curtain ( t ∼ +25 days) was found near the time of first soft X-ray detection ( t = 35.6 days). 6) Transition ( t = 35–60 days); Brightness decreases where and FWHM gradually increase meaning it reveals deeper pseudo-photosphere. 7) Final decline (t = 60∼75 days); Nova is fainter than 6 magnitude from maximum, and FWHM decrease, Nova is now in nebular phase permanently allowing us to see the surface of white dwarf for the first time.

Source: Journal of Physics Conference Series

DOI: 10.1088/1742-6596/1144/1/012014