SN 1990U was a

type Ic supernova Type Ib and Type Ic supernovae are categories of supernovae that are caused by the stellar core collapse of massive stars. These stars have shed or been stripped of their outer envelope of hydrogen, and, when compared to the spectrum ...

event in the nucleus of the galaxy

NGC 7479 NGC 7479 (also known as Caldwell 44 or the Superman Galaxy) is a barred spiral galaxy about 105 million light-years away in the constellation Pegasus (constellation), Pegasus. William Herschel discovered it in 1784. NGC 7479 is also recognized a ...

. It was discovered July 27, 1990 by the Berkeley Automated Supernova Search after reaching magnitude . Initially this was classified as a Type Ib supernova, but the weakness of the neutral helium

absorption line A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from emission or absorption of light in a narrow frequency range, compared with the nearby frequencies. Spectral lines are often used to iden ...

s led to a reclassification.

References

External links

Spectra
on th
Open Supernova Catalog

Simbad

Image SN 1990U
Pegasus (constellation) Supernovae {{var-star-stub