Stars hum themselves to death

Supernova 1987A in its dying moments

Milliseconds before a giant star dies in a spectacular explosion, it hums a note, astronomers say.

    “Our simulations show that the inner core starts to execute pulsations… about 500 milliseconds [after the core collapses] the inner core begins to vibrate wildly. And after 600, 700 or 800 milliseconds, this oscillation becomes so vigorous that it sends out sound waves. In these computer runs, these sound waves actually cause the star to explode, not the neutrinos.”

The researchers say typical sound frequencies in the inner core are about 200 to 400 hertz, in the audible range around middle C.