Supernova 1996L: evidence of a strong wind episode before the explosion

Details Supernova 1996L: evidence of a strong wind episode before the explosion Supernova 1996L: evidence of a strong wind episode before the explosion

1999-01-25

arxiv.org/abs/astro-ph/9901345v1

Astronomy and Astrophysics

Astrophysics

8 pages, 6 figures, Latex, To appear in M.N.R.A.S

Scientific paper

10.1046/j.1365-8711.1999.02499.x

Observations of the type II SN 1996L reveal the presence of a slowly expanding (V~700$ km/s) shell at ~ 10^(16) cm from the exploding star. Narrow emission features are visible in the early spectra superposed on the normal SN spectrum. Within about two months these features develop narrow symmetric P-Cygni profiles. About 100 days after the explosion the light curve suddenly flattens, the spectral lines broaden and the Halpha flux becomes larger than what is expected from a purely radioactive model. These events are interpreted as signatures of the onset of the interaction between the fast moving ejecta and a slowly moving outer shell of matter ejected before the SN explosion. At about 300 days the narrow lines disappear and the flux drops until the SN fades away, suggesting that the interaction phase is over and that the shell has been swept away. Simple calculations show that the superwind episode started 9 yr before the SN explosion and lasted 6 yr, with an average dM/dt=10^(-3) M_solar/yr. Even at very late epochs (up to day 335) the typical forbidden lines of [OI], CaII], [FeII] remain undetected or very weak. Spectra after day 270 show relatively strong emission lines of HeI. These lines are narrower than other emission lines coming from the SN ejecta, but broader than those from the CSM. These high excitation lines are probably the result of non-thermal excitation and ionization caused by the deposition of the gamma-rays emitted in the decay of radioactive material mixed in the He layer.

Affiliated with

Also associated with

No associations

Rating

Supernova 1996L: evidence of a strong wind episode before the explosion does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Supernova 1996L: evidence of a strong wind episode before the explosion, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Supernova 1996L: evidence of a strong wind episode before the explosion will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-494468