The type II supernova 1988Z in MCG +03-28-022 : increasingevidence of interaction of supernova ejecta with a circumstellar wind.
Abstract
We present a set of optical observations of SN 1988Z covering a period of 3 yr from the discovery. This relatively bright supernova shows an unusual photometric behaviour, with broad light curves in the B, V and R bands resembling those of SN 1987F. The colour evolution is unique, with a slow blueward evolution in the early months, after which it remains nearly constant. The spectrum is characterized at all epochs by strong Balmer emission, without the usual P Cygni absorption component which is typical of SNeII at early stages. Several He I emission lines are also visible. These lines have a complex structure, with several components evolving with time with respect to both width and intensity. The Hα luminosity decline is exceptionally slow and cannot be explained by a simple radioactive model, so this object is an ideal candidate for a supernova in which there is interaction of the SN ejecta with a circumstellar wind. A number of unresolved, forbidden emission lines of [O III], [N II], [Ne III], [Fe II], [Fe III], [Fe VII], [Fe x] and, tentatively, of [Fe xI], [A x] and [Ca V] have been identified. Their presence and relative strengths suggest the existence of a shock, which gives further support to the theory of an ejecta-wind interaction.
- Publication:
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Monthly Notices of the Royal Astronomical Society
- Pub Date:
- May 1993
- DOI:
- Bibcode:
- 1993MNRAS.262..128T
- Keywords:
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- H Alpha Line;
- Light Curve;
- Stellar Envelopes;
- Stellar Spectra;
- Stellar Winds;
- Supernovae;
- Astronomical Photometry;
- Forbidden Bands;
- Astrophysics