The Line Emission from the Circumstellar Gas around SN 1987A

Abstract

view Abstract Citations (118) References (98) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Line Emission from the Circumstellar Gas around SN 1987A Lundqvist, Peter ; Fransson, Claes Abstract The narrow emission lines from the inner ring around SN 1987A during the first ~2000 days are modeled assuming that the ring was ionized by radiation accompanying the supernova breakout. The analysis extends that published by Lundqvist & Fransson in 1991 to include an improved description for the geometry, a multidensity structure of the emitting gas, results from improved calculations for the evolution of the EUV radiation from the outburst, and updated atomic data. To model the light curves of the lines, the ring has to be optically thick to the ionizing radiation, as is the case for a ring geometry, but not for a spherical shell. The density of the observed gas in the ring ranges from (6.0 +/- 1.0) x 10^3^ cm^-3^ to 3.3 x 10^4^ cm^-3^. The early (t <~ 410 days) UV line emission is dominated by the gas with the highest density, while the late time optical emission originates in the low-density gas. Gas of lower density than ~6 x 10^3^ cm^-3^ may be present in the ring but will not dominate the emission until after 2000 days. The ionized mass of the gas in the ring observed up to day 1882 is ~4.5 x 10^-2^ M_sun_. The He/H ratio is 0.25 +/- 0.05, and the overall abundance of C, N, and O is 0.30 +/- 0.05 times solar with relative abundances N/C = 5.0 +/- 2.0 and N/O = 1.1 +/- 0.4. Good fits to the light curves are obtained for a peak effective temperature of the burst in the range (5-8) x 10^5^ K. The corresponding color temperature is (1.0-1.5) x 10^6^ K. To model the N V λ1240 light curve, resonance scattering in a medium external to the ring is needed. It is shown that the N V line scattering can be used to discriminate between models for the formation of the inner ring and the nebulosity connected to it. In particular, the structure inferred from the N V line scattering is qualitatively consistent with that in the interacting winds model. Publication: The Astrophysical Journal Pub Date: June 1996 DOI: 10.1086/177380 arXiv: arXiv:astro-ph/9512025 Bibcode: 1996ApJ...464..924L Keywords: STARS: CIRCUMSTELLAR MATTER; STARS: SUPERNOVAE: INDIVIDUAL ALPHANUMERIC: SN 1987A; ULTRAVIOLET: ISM; Astrophysics E-Print: 38 pages PostScript, 7 PostScript figures may be retrieved from ftp://www.astro.su.se/pub/supernova/lf95_87A/ Accepted for publication in ApJ full text sources arXiv | ADS | data products SIMBAD (2) NED (2) MAST (1) INES (1)