STARS are round – that’s the received wisdom. But Regulus, the brightest star in the constellation Leo, is shaped like a pumpkin. That’s because it is spinning so fast it can barely hold itself together. Now we may know why it whirls so quickly: another star dumped material onto it millions of years ago.
In 2004, astronomers discovered that Regulus’s equatorial diameter is 32 per cent greater than its polar diameter. Now Douglas Gies of Georgia State University in Atlanta and colleagues have found it has a faint companion star. The unseen star betrayed its presence through its gravitational pull, which causes Regulus to wobble to and…
