A star seldom just flies apart – at least not when it’s in the prime of life. But some of them come close. One of the best examples is Regulus, the brightest star of Leo. It’s rotating so fast that it’s barely holding itself together.
Regulus consists of four stars, but only one of them is bright enough to see with the eye alone. It’s known as Regulus A. It’s more than four times wider and heavier than the Sun. And it spins much faster – about 200 miles per second at the equator – almost 200 times faster than the Sun.
According to studies, that’s 96 and a half percent of the speed required to make Regulus fly apart. The high speed pushes gas outward, so Regulus is about 30 percent wider through the equator than the poles.
The star was spun up by a now-dead companion star. That star was more massive than Regulus A, so it lived a shorter life. As it expired, it puffed up. Regulus A then pulled gas from its surface. As the gas piled up on Regulus A, it added momentum to the star’s rotation – like pushing harder and harder on a spinning globe.
The companion eventually lost all its outer layers. That left only its dead core, known as a white dwarf – a star that did fly apart, but not until the end of its life.
Regulus stands close to the right or lower right of the Moon at nightfall. They stay close together as they drop down the western sky. They set around midnight.
Script by Damond Benningfield