NASA/IPAC EXTRAGALACTIC DATABASE
Date and Time of the Query: 2019-06-18 T14:52:35 PDT
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Notes for object SN 1990B

1 note(s) found in NED.


1. 2001AJ....121.1648M
Re:SN 1990B
SN 1990B. - The BASS also discovered this SN on 1990 January 20 in
NGC 4568 at magnitude 16 (Perlmutter & Pennypacker 1990). We find a
recession velocity for the SN of 2200 km s^-1^ from narrow H{alpha}
emission from an H II region, while the listed galactic velocity for
NGC 4568 is 2255 km s^-1^. The lack of hydrogen lines indicated that the
SN was of Type I (Dopita & Ryder 1990), and subsequent spectra confirmed
that it was an SN Ib (Filippenko, Spinrad, & Dickinson 1990; Kirshner &
Leibundgut 1990; Benetti, Cappellaro, & Turatto 1990a). Later analysis
indicated that SN 1990B was actually a Type Ic SN (Clocchiatti et al.
2001); at the earlier stages, the existence of a separate subclass of
helium-poor Type I SNe (i.e., the SNe Ic) had yet to be demonstrated. Radio
emission was also detected from SN 1990B (Sramek, Weiler, & Panagia 1990;
Van Dyk et al. 1993). Some of the spectra shown here (Fig. 2) are also
presented by Clocchiatti et al. (2001). Our first three spectra (1990
January 23, February 10, and February 27) show some absorption features,
but they do not exhibit the full set of helium lines that would indicate
an SN Ib; thus SN 1990B is an SN Ic according to our spectra; see, however,
section 4.2. By 1990 March 25, the SN had begun to enter the nebular phase.


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