Time-Domain · 4

Explosive Transients

The supernovae and novae — the thermonuclear and core-collapse explosions of stars.

Classical NovaTransient class
Light (optical)
A thermonuclear runaway on the surface of a white dwarf that is accreting matter from a companion star. Unlike a supernova, the white dwarf survives, and the outburst can recur.
Core-Collapse SupernovaTransient class
Light + neutrinos (+ gravitational waves)
The catastrophic collapse of the core of a massive star, which rebounds into an explosion and leaves a neutron star or black hole. Most of the energy escapes as neutrinos — first detected from SN 1987A — making these among the earliest multi-messenger sources.
HypernovaTransient class
Light + gamma rays
An exceptionally energetic core-collapse explosion of a very massive star, releasing far more kinetic energy than an ordinary supernova. Hypernovae from rapidly-rotating collapsars are thought to power the long gamma-ray bursts.
Type Ia SupernovaTransient class
Light (optical/near-IR)
The thermonuclear detonation of a white dwarf that has been pushed over a critical mass. Their remarkably uniform peak brightness makes them the standard candles that measured the accelerating expansion of the universe.