Stars as Laboratories for Fundamental Physics - MPP Theory Group

414 Chapter 11
initial neutrino flux may be characterized by a decreasing radius (decreasing
flux), yet increasing temperature. For an overview of various
model calculations see Burrows (1990b). One should be careful not to
take details of the time evolution of the temperature and luminosity of
any specific calculation too seriously.
11.3 SN 1987A Neutrino Observations
11.3.1 Supernova 1987A
Shelton’s (1987) sighting of a supernova (SN 1987A) in the Large Magellanic
Cloud (LMC), a small satellite galaxy of the Milky Way at a
distance from us of about 50 kpc (165,000 ly), marked the discovery
of the closest visual SN since Kepler’s of 1604. It was close enough
that several underground detectors which were operational at the time
were able to measure the neutrino flux from the core collapse of the
progenitor star, the blue supergiant Sanduleak −69 202. The observed
neutrinos were registered within a few seconds of 7:35:40 UT (universal
Fig. 11.9. Early optical observations of SN 1987A according to the IAU
Circulars, notably No. 4316 of February 24, 1987. The times of the IMB,
Kamiokande II (KII) and Baksan (BST) neutrino observations (23:07:35)
and of the Mont Blanc events (23:02:53) are also indicated. The solid line
is the expected visual brightness, the dotted line the bolometric brightness
according to model calculations. (Adapted, with permission, from Arnett
et al. 1989, Annual Review of Astronomy and Astrophysics, Volume 27,
c⃝ 1989, by Annual Reviews Inc.)