We present 42 low-resolution spectra of supernova (SN) 1993J, our complete collection from the Lick and Keck observatories, from day 3 after explosion to day 2454, as well as one Keck high-dispersion spectrum from day 383. SN 1993J began as an apparent SN II, albeit an unusual one. After a few weeks, a dramatic transition took place, as prominent helium lines emerged in the spectrum. SN 1993J had metamorphosed from a SN II to a SN IIb. Nebular spectra of SN 1993J closely resemble those of SNe Ib and Ic, but with a persistent Hα line. At very late times, the Hα emission line dominated the spectrum, but with an unusual, boxlike profile. This is interpreted as an indication of circumstellar interaction.
展开▼
机译：从爆炸后的第3天到2454天，我们从利克和凯克天文台收集了42个超新星（SN）1993J的低分辨率光谱，以及第383天的一个Keck高色散光谱。明显的SN II，尽管不寻常。几周后，光谱中出现了明显的氦气线，发生了戏剧性的过渡。 SN 1993J已从SN II变形为SN IIb。 SN 1993J的星云光谱与SNe Ib和Ic极为相似，但具有持久的Hα线。在很晚的时候，Hα发射线主导了光谱，但是具有不寻常的盒状轮廓。这被解释为是星际相互作用的指示。
展开▼
