Our newsletter logo is this three-ring picture of Supernova 1987A with a beautiful naturally occuring symmetry (full size image). The Department of Physics and Astronomy is associated with this supernova since the Irvine-Michigan-Brookhaven (IMB) water-Cherenkov proton decay and neutrino detector was one of at least two installations to detect neutrinos coming from this supernova. They detected eight neutrinos over about ten seconds, and the Kamionkande detector in Japan detected neutrinos at the same time. The detection of neutrinos in about the amount predicted by theory confirmed that neutrino production is the principal method by which most of the energy (10^53 ergs) is converted from gravitational collapse to a neutron star and rapidly radiated away in a few seconds. The kinetic energy of the ejecta is only about 1% of the total energy, and the optical signal is less. The new Super-Kamiokande detector collaboration involves U. C. Irvine, and will be seven times more sensitive to neutrinos from supernova explosions. This supernova is located in our neighboring dwarf galaxy in the Southern hemisphere, the Large Magellenic Cloud, at about 170,000 light years away. The heavier elements are also created in the stars that eventually collapse to form neutron stars, and the explosions release them to the galaxy to form new stars and planets.The Hubble Space Telescope image from the Wide Field Planetary Camera shows the rings of ionized gas in the vicinity of SN 1987A, earlier imaged from the ground by Arlin Crotts and Joe Wampler in 1990-91. Recent ground-based optical spectra demonstrate that the gas is very slow moving (less than 25 km/sec for the larger rings, and 10 km/sec for the smaller central ring) and so it must have been ejected from the progenitor star twenty to thirty thousand years before the supernova explosion. Such ejection, in the form of winds from both red and blue supergiants, is common among massive stars. Here is the press release and an early model of the rings.
The unity of particle physics, astrophysics, plasma physics, and the formation of heavy elements for condensed matter physics revealed in this event also motivates us to use it as our newsletter logo.