Stars hum ‘middle C’ before death
`Milliseconds before a giant star dies in a spectacular explosion, it hums a note around ‘middle C’, astronomers say. [..]
“Our simulations show that the inner core starts to execute pulsations,” says Professor Burrows.
“They show that after 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.”‘