Epsilon Coronae Australis (ε CrA), is a

star A star is an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked ...

system located in the constellation

Corona Australis Corona Australis is a constellation in the Southern Celestial Hemisphere. Its Latin name means "southern crown", and it is the southern counterpart of Corona Borealis, the northern crown. It is one of the 48 constellations listed by the 2nd-centu ...

. Varying in brightness between

apparent magnitude Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's li ...

s of 4.74 to 5 over 14 hours, it is the brightest

W Ursae Majoris variable A W Ursae Majoris variable, also known as a low mass contact binary, is a type of eclipsing binary variable star. These stars are close binaries of spectral types F, G, or K that share a common envelope of material and are thus in contact with one ...

(low mass contact binary) in the night sky.

Naming

Nicolas Louis de Lacaille Abbé Nicolas-Louis de Lacaille (; 15 March 171321 March 1762), formerly sometimes spelled de la Caille, was a French astronomer and geodesist who named 14 out of the 88 constellations. From 1750 to 1754, he studied the sky at the Cape of Good ...

gave Epsilon Coronae Australis its Bayer designation. It is also known as HR 7152, and HD 175813.

Properties

Epsilon Coronae Australis is an F4V dwarf star with an effective temperature of 6000 Kelvin. It ranges between

s of 4.74 to 5 over 14 hours, an absolute magnitude of +2.45, and a mass of 1.1 solar masses. Epsilon Coronae Australis is a

, indicating that it has a contact companion within the Roche Limit of the primary. The star is located at a distance of 30 pc (97 light years) from the Sun. Yildiz and colleagues estimated the age of the system at 2.83 ± 0.28 billion years based on study of the properties of the system and estimated rate of mass transfer. They found the current masses of the primary and secondary to be 1.72 ± 0.04 and 0.22 ± 0.02 solar masses respectively, from their original masses of 1.06 ± 0.03 and 2.18 ± 0.06 solar masses.

Notes

References

{{DEFAULTSORT:Epsilon Coronae Australis Corona Australis Corona Australis, Epsilon Corona Australis, Epsilon W Ursae Majoris variables Durchmusterung objects 7152 175813 093174