Regulus: The Heart of the Lion

By: Monica Mahajan - 4th period

What is Regulus?

Regulus is a star which is part of the constellation Leo. It is bluish-white in color, and its spectral classification falls under B.

Why Is Regulus Called "The Heart of The Lion"?

Regulus is given this honorable name due to its location. It is the closest star to the lion's heart in the constellation Leo. Regulus is also called:

- The Kingly One,

- Little King,

- Alpha Leonis, and

- a few other names

Terms To Know

Light Year

A unit of measure for distance. A light year is the distance light can travel in one year.


How much energy, or light, a star gives off from its surface.

Absolute Magnitude

How bright a star looks from a standard distance of 36.2 light-years.

Apparent Magnitude

How bright a star looks like from Earth.

Compared To Our Sun...

- Regulus is about 3.5 times more massive than our sun.

- This star surface temperature is 12,000 K (about 21,000 degrees Fahrenheit!), much hotter than our Sun's surface temperature.

- The luminosity of Regulus is 240 L, whereas the Sun's is 1 L.

- Regulus is about 50 million years old, while the Sun is about 5 billion years old!

- Regulus is a main sequence star, like the Sun.

Other Statistics

- Apparent magnitude: 1.36

- Absolute magnitude: -0.52

- Right ascension: 10 hrs, 8 min, 22.3 sec

- one of the two coordinates of a point on the celestial sphere (part of equatorial coordinate system)

- Declination: +11 degrees, 58 min, 2 sec

- the other coordinate

- About 78 light years away from Earth!

Did You Know...

Regulus is the brightest star in its constellation, making it the 21st brightest star in the night sky!

To see the other brightest stars, click...

Regulus has been used as a name in Harry Potter, a book series by J.K. Rowling. Sirius Black's brother in the series was named Regulus Black, for the brightest star in the sky, even though it really isn't.