Look east at 8 p.m. to see majestic Leo the Lion well above the eastern horizon. If you consider Leo to be a lion resting on his stomach with his paws out in front, the head and chest of Leo face west and look like a backward “question mark” or sickle in the sky somewhat lying on its side. This part of Leo consists of five fairly bright stars in the sickle portion with the very bright star Regulus acting as the handle of the sickle or the dot on the question mark.
Regulus is the 21st-brightest star in the sky. It is 79 light years away and has luminosity 360 times that of the sun. Regulus spins so fast on its axis it is an oblate egg-shaped object rather than a sphere like the sun. When we look at Regulus, we are actually seeing a quadruple star system. A tiny white dwarf star goes around Regulus every 40 days, and a close pair of stars also goes around Regulus every 125,000 years. Thus, like many of the bright stars in our sky, Regulus is a strange star indeed compared to the sun.
Leo’s rump is to the east and is a triangle of bright stars. The brightest star in Leo’s rump and the star on the far eastern end of the rump is Denebola (lion’s tail in Arabic), the 61st-brightest star in the sky. Denebola is a favorite of amateur astronomers due to its brightness and its catchy name. Denebola is a white dwarf star 36 light years away with a surface temperature of 8,500 degrees Kelvin. The sun has a surface temperature of 5,800 degrees Kelvin. Regulus and Denebola help make Leo the King of the Beasts.