SN 1987A

SN 1987A is a 1987 supernova in the Large Magellanic Cloud (LMC), about 168000 light-years away, whose light reached Earth on February 23, 1987. Its apparent magnitude at its brightest was +3 in May 1987 (to our view, the brightest recorded since SN 1604), and I believe it is the only recorded supernova visible without a telescope since the 1800s. Three neutrino detectors, the Kamioka Observatory, the IMB, and the Baksan Neutrino Observatory, detected bursts of neutrinos coincident with the supernova EMR reaching Earth. The supernova has been much studied since.

It is considered a core collapse supernova and a portion of their study consists of the study of their remnants. The SN 1987A remnant has more circular symmetry than spherical, suggesting the progenitor's stellar rotation was a factor. Observations of the light curve have shown that the explosion was highly asymmetric, i.e., an anisotropic explosion. There is effort to identify a resulting neutron star, e.g., by comparing observations to observed characteristics of remnants where there is clearer evidence of a neutron star. An apparent pulsar wind nebula (PWN) has been observed.