Regulus is the heart of Leo, a hot blue-white star spinning so fast that it bulges at the equator, sitting almost exactly on the path of the planets.
At a glance
| type | blue-white star (class B) |
|---|---|
| distance from the Sun | 79.3 light-years (24.3 pc) |
| its light left it | 79.3 years ago |
| luminosity | 316 × the Sun |
| radius | 4.35 × the Sun |
| surface temperature | 12,500 K |
| constellation | Leo (Lion) |
Read off the piece’s own catalogue, the same values it draws with.
About Regulus
Regulus is a hot main-sequence star, larger and much more luminous than the Sun. It rotates close to the limit at which it would start to shed material from its equator, so it is strongly flattened, with cooler, dimmer equatorial regions than poles.
It lies very close to the ecliptic, the line the Sun, Moon and planets follow across the sky, so the Moon often passes in front of it and planets sometimes pass close by. Regulus is part of a multiple system: a fainter pair of stars travels with it at a wide separation.
What you see in the piece
With HUMAN EYE on it marks the base of the sickle of Leo, a bright blue-white point. Close up the disc is hot and blue-white.
Measured or modelled
Small, regular shifts in its spectrum suggest a very close, faint companion, most likely a white dwarf. Such a companion could explain the fast spin, if Regulus took on mass and spin from it in the past.
Questions
Why does Regulus spin so fast?
It rotates close to its break-up speed, perhaps because it gained mass and spin from a companion; the result is a strongly flattened star.