Detection of preshock dense circumstellar material of SN 1978K

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

Research output: Contribution to journalArticlepeer-review


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.

Original languageEnglish (US)
Pages (from-to)L51-L54
JournalAstrophysical Journal
Issue number1 PART 2
StatePublished - Feb 10 1999


  • Circumstellar matter
  • Galaxies: Individual (NGC 1313)
  • Stars: Mass loss
  • Supernovae: Individual (SN 1978K)

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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