Denebola (β Leo / β Leonis / Beta Leonis) is the second brightest star in the constellation Leo. It is an A-class star that is about distant from earth, and has a luminosity about twelve times that of the sun. Its apparent magnitude is 2.14. Denebola is a Delta Scuti type variable star, meaning its luminosity varies very slightly over a period of a few hours.
In Johann Bayer's Uranometria, published in 1603, the star was designated β Leonis; for the second-brightest star in the constellation of Leo. In 1725, John Flamsteed designated this star 94 Leo. (The Flamsteed designation was assigned on the basis of increasing right ascension within the constellation, rather than luminosity.) Additional designations followed as this star was recorded in subsequent star catalogues.
The surface temperature of Denebola is about 8500 K. It has a high rotation velocity of at least 120 km/s, which is of the same order of magnitude as the very rapidly rotating star Achernar. Compare this to the Sun's more leisurely equatorial rotation velocity of 2 km/s. This star is believed to be a δ Scuti-type variable star that exhibits fluctuations in luminosity of 0.025 magnitudes roughly ten times per day.
Denebola shows a strong infrared excess, which means there must be a debris disk of cool dust in orbit around it. As our solar system is believed to have formed out of such a disk, Denebola and similar stars such as Vega and Beta Pictoris may be good candidate locations for extrasolar planets. The dust surrounding Denebola has a temperature of about . Unsuccessful attempts have been made to image the dust disk, implying that the disk contains much less material than that surrounding Beta Pictoris, which has been imaged frequently.
Kinematic studies have shown that Denebola is part of a stellar association dubbed the IC 2391 supercluster. All the stars of this group share a roughly common motion through space, although they are not gravitationally bound. This implies that they were born in the same location, and perhaps initially formed an open cluster. Other stars in this association include Alpha Pictoris, Beta Canis Minoris and the open cluster IC 2391. In total more than sixty probable members of the group have been identified.