Twenty Years of Supernova 1987A

The unique supernova SN 1987A has been a bonanza for astrophysicists. It provided several observational 'firsts', like the detection of neutrinos from the core collapse, the observation of the progenitor star on archival photographic plates, the signatures of a non-spherical explosion and mixing in the ejecta, the direct observation of supernova nucleosynthesis, including accurate masses of 56Ni, 57Ni and 44Ti, observation of the formation of dust in the supernova, as well as the detection of circumstellar and interstellar material. Now, after 20 years, it continues to be an extremely exciting object as we will be able to observe the supernova shock interacting with the circumstellar ring in real time.