Magnitude 4.04 Apparent magnitude (V) 4.04 | Constellation Eridanus | |
Similar Theta Eridani, Gamma Eridani, Zeta Eridani, Delta Eridani, 40 Eridani | ||
Omicron1 Eridani, also named Beid, is a star in the constellation of Eridanus. With an apparent visual magnitude of 4.04, it is visible to the naked eye on a clear, dark night. Based upon parallax measurements, it lies approximately 122 light-years from the Sun.
Omicron1 Eridani is an evolved F-type giant star with a stellar classification of F0 III. It is a Delta Scuti variable star that undergoes non-radial pulsations, with a variation of just 0.03 magnitude over a period of 0.0747 days. The star is spinning rapidly with a projected rotational velocity of 108.1 km/s and a rotation period of less than around 1.9 days. This is creating an equatorial bulge that is 11% wider than the polar radius. Omicron1 Eridani has nearly double the mass of the Sun, 3.7 times the Sun's radius, and shines with 27 times the solar luminosity from an outer atmosphere at an effective temperature of 6,963 K.
Nomenclature
ο1 Eridani (Latinised to Omicron1 Eridani) is the star's Bayer designation. It also bears the Flamsteed designation 38 Eridani.
In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalogue and standardize proper names for stars. The WGSN approved the name Beid for this star on 12 September 2016 and it is now so entered in the IAU Catalog of Star Names.
In Chinese, 九州殊口 (Jiǔ Zhōu Shū Kǒu), meaning Interpreters of Nine Dialects, refers to an asterism consisting of Omicron1 Eridani, 39 Eridani, Xi Eridani, Nu Eridani, 56 Eridani and 55 Eridani. Consequently, Omicron¹ Eridani itself is known as 九州殊口二 (Jiǔ Zhōu Shū Kǒu èr, English: the Second Star of Interpreters of Nine Dialects.)