Detection of Preshock Dense Circumstellar Material of SN 1978K

February 1999 • 1999ApJ...512L..51C

Authors • Chu, You-Hua • Caulet, Adeline • Montes, Marcos J. • Panagia, Nino • Van Dyk, Schuyler D. • Weiler, Kurt W.

Abstract • The supernova SN 1978K has been noted for its lack of emission lines broader than a few thousand kilometers per second since its discovery in 1990. Modeling of the radio spectrum of the peculiar SN 1978K indicates the existence of H II absorption along the line of sight. To determine the nature of this absorbing region, we have obtained a high-dispersion spectrum of SN 1978K at the wavelength range 6530-6610 Å. The spectrum shows not only the moderately broad Hα emission of the supernova ejecta but also narrow nebular Hα and [N II] emission. The high [N II] λ6583/Hα ratio, 0.8-1.3, suggests that this radio-absorbing region is a stellar ejecta nebula. The expansion velocity and emission measure of the nebula are consistent with those seen in ejecta nebulae of luminous blue variables. Previous low-dispersion spectra have detected a strong [N II] λ5755 line, indicating an electron density of (3-12)×10⁵ cm^-3. We argue that this stellar ejecta nebula is probably part of the preshock dense circumstellar envelope of SN 1978K. We further suggest that SN 1997ab may represent a young version of SN 1978K.

Links

• SIMBAD http://simbad.u-strasbg.fr/simbo.pl?bibcode=1999ApJ...512L..51C
• NED https://ned.ipac.caltech.edu/uri/NED::InRefcode/1999ApJ...512L..51C
• PREPRINT http://arxiv.org/abs/astro-ph/9812240
• ELECTR https://doi.org/10.1086%2F311866
• SPIRES http://inspirehep.net/search?p=find+eprint+astro-ph/9812240