Regulus (α Leo / α Leonis / Alpha Leonis) is the brightest star in the constellation Leo and one of the brightest stars in the nighttime sky.

Regulus is approximately 77.5 light years from Earth's Solar System. Its name is Latin for "prince".

It has about 3.5 times the Sun's mass, and is a young star only a few hundred million years old. It is spinning extremely rapidly, with a rotation period of only 15.9 hours, which causes it to have a higly oblate egg shape. This results in gravity darkening : its poles are considerably hotter and brighter than its equator. If it was rotating only 10% faster the centripetal force of gravity would not be enough to keep it from tearing itself apart.

Statistics

• Visual magnitude: 1.4
• Spectral type: B7 V
• Radial velocity: 4 km/s
• Proper Motion: 0.249 arcsecs/year
• Apparent Visual Magnitude: 1.36
• Absolute Visual Magnitude: -0.52
• Luminosity: 331 Solar Luminosities

Astrology

It was also one of the four "royal stars" of the Persians from around 3000 BC. In the religion of Stregheria, Regulus is a fallen angel and quarter guardian of the southern gate .

Fiction

• The distance from Regulus to Deep Space Nine, in the Star Trek series of the same name, is 300 light-years.

External links

• Astronomers: ‘Bullet star’ shines 350 times brighter than the sun
• Portrait of a Star on the Edge
• Egg-Shaped Regulus is Spinning Fast