Epsilon Scorpii
Binary giant star in Scorpius, fifth brightest in the constellation.
Epsilon Scorpii is a binary star in the southern zodiac constellation of Scorpius. The primary component, which has the proper name Larawag, is the fifth-brightest member of the constellation with an apparent visual magnitude of around +2.3. Parallax measurements from the Hipparcos mission place it at a distance of 63.7 light-years.
Quick Facts
- Bayer designation
- ε Scorpii
- Proper name
- Larawag
- Apparent visual magnitude
- +2.3
- Distance
- 63.7 ly
- Stellar classification
- K1 III
- Mass
- 1.41 M☉
- Radius
- 13 R☉
Facts from the source article.
Characteristics
This orange-hued giant star, known as Larawag, has a spectral type of K1 III, meaning it left the main sequence after burning through its core hydrogen. Now roughly 13 times the Sun’s width and 1.41 times its mass, the star fuses helium in its core, placing it on the horizontal branch and within the red clump on a color-magnitude diagram. Its outer layers reach an effective temperature of 4,522 K, producing the characteristic color of a cool K-type star. Though listed as a suspected variable with a possible brightness range of 2.23 to 2.35, Hipparcos data revealed fluctuations of only 0.01 to 0.02 magnitudes. The star also emits X-rays. In 2018, astronomers identified a faint companion, designated B, moving together with the primary across the sky at a separation of 14.4 arcseconds. This secondary star is far smaller and dimmer, possessing just 0.26% of the primary’s mass, 0.29% of its radius, and less than 1% of the Sun’s luminosity.
Nomenclature
Epsilon Scorpii, also known by its Bayer designation ε Scorpii, carries the traditional name Larawag from the Wardaman people of Australia's Northern Territory, meaning "clear sighting." The International Astronomical Union's Working Group on Star Names officially approved Larawag for Epsilon Scorpii A in November 2017, and it now appears on the IAU's list of approved star names. Astronomer Patrick Moore proposed the Chinese name Wei for this star, but that was likely a mistake. Wei actually refers to the Chinese asterism Tail, which includes Epsilon Scorpii along with several other stars. The star's proper Chinese name is the Second Star of Tail.
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