Epsilon Leonis
Encyclopedia
Epsilon Leonis (ε Leo, ε Leonis) is the fifth brightest star
in the constellation
Leo
, consistent with its Bayer designation
Epsilon. The star has the traditional names Ras Elased (Australis), Asad Australis and Algenubi, all of which derive from the Arabic رأس الأسد الجنوبي rās al-’asad al-janūbī, which means "the southern (star) of the lion's head"; australis is Latin for "southern".
is G1 II. However, it is much larger and brighter than the Sun with a luminosity 360 times and a diameter 23 times solar. Consequently, its absolute magnitude
is actually -1.46, making it one of the more luminous stars in the constellation, significantly more than its alpha star, Regulus
. Algenubi's apparent brightness
, though, is only 2.975. Given its distance of about 250 light years from Earth
, the star is more than 3 times the distance from us than Regulus.
Algenubi exhibits the characteristics of a Cepheid variable
, changing by approximately 1/10 magnitude
every few days.
Star
A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...
in the constellation
Constellation
In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....
Leo
Leo (constellation)
Leo is one of the constellations of the zodiac. Its name is Latin for lion. Its symbol is . Leo lies between dim Cancer to the west and Virgo to the east.-Stars:...
, consistent with its Bayer designation
Bayer designation
A Bayer designation is a stellar designation in which a specific star is identified by a Greek letter, followed by the genitive form of its parent constellation's Latin name...
Epsilon. The star has the traditional names Ras Elased (Australis), Asad Australis and Algenubi, all of which derive from the Arabic رأس الأسد الجنوبي rās al-’asad al-janūbī, which means "the southern (star) of the lion's head"; australis is Latin for "southern".
Properties
Epsilon Leonis is a G class star similar to the Sun. Its stellar classificationStellar classification
In astronomy, stellar classification is a classification of stars based on their spectral characteristics. The spectral class of a star is a designated class of a star describing the ionization of its chromosphere, what atomic excitations are most prominent in the light, giving an objective measure...
is G1 II. However, it is much larger and brighter than the Sun with a luminosity 360 times and a diameter 23 times solar. Consequently, its absolute magnitude
Absolute magnitude
Absolute magnitude is the measure of a celestial object's intrinsic brightness. it is also the apparent magnitude a star would have if it were 32.6 light years away from Earth...
is actually -1.46, making it one of the more luminous stars in the constellation, significantly more than its alpha star, Regulus
Regulus
Regulus is the brightest star in the constellation Leo and one of the brightest stars in the night sky, lying approximately 77.5 light years from Earth. Regulus is a multiple star system composed of four stars which are organized into two pairs...
. Algenubi's apparent brightness
Apparent magnitude
The apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, adjusted to the value it would have in the absence of the atmosphere...
, though, is only 2.975. Given its distance of about 250 light years from Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
, the star is more than 3 times the distance from us than Regulus.
Algenubi exhibits the characteristics of a Cepheid variable
Cepheid variable
A Cepheid is a member of a class of very luminous variable stars. The strong direct relationship between a Cepheid variable's luminosity and pulsation period, secures for Cepheids their status as important standard candles for establishing the Galactic and extragalactic distance scales.Cepheid...
, changing by approximately 1/10 magnitude
Magnitude (astronomy)
Magnitude is the logarithmic measure of the brightness of an object, in astronomy, measured in a specific wavelength or passband, usually in optical or near-infrared wavelengths.-Background:...
every few days.
See also
- Lists of stars in the constellation Leo
- Class G Stars
- Variable starVariable starA star is classified as variable if its apparent magnitude as seen from Earth changes over time, whether the changes are due to variations in the star's actual luminosity, or to variations in the amount of the star's light that is blocked from reaching Earth...
- Algenubi in fiction
External links
- Jim Kaler's Stars:Algenubi