Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
---|---|
Constellation | Corvus |
Right ascension | 12h 34m 23.23484s[1] |
Declination | −23° 23′ 48.3374″[1] |
Apparent magnitude (V) | 2.647[2] |
Characteristics | |
Spectral type | G5 II[3] |
U−B color index | +0.586[2] |
B−V color index | +0.898[2] |
R−I color index | +0.44[4] |
Astrometry | |
Radial velocity (Rv) | −7.6[5] km/s |
Proper motion (μ) | RA: +1.11[1] mas/yr Dec.: −56.56[1] mas/yr |
Parallax (π) | 22.39 ± 0.18 mas[1] |
Distance | 146 ± 1 ly (44.7 ± 0.4 pc) |
Absolute magnitude (MV) | –0.61[6] |
Details | |
Mass | 3.7±0.1[3] M☉ |
Radius | 16[7] R☉ |
Luminosity | 164[8] L☉ |
Surface gravity (log g) | 2.52±0.03[3] cgs |
Temperature | 5,100±80[3] K |
Metallicity [Fe/H] | –0.01[6] dex |
Rotational velocity (v sin i) | 8[9] km/s |
Age | 206[3] Myr |
Other designations | |
Database references | |
SIMBAD | data |
Beta Corvi or β Corvi, officially named Kraz (/ˈkræz/),[11] is the second-brightest star in the southern constellation of Corvus with an apparent visual magnitude of 2.647.[2] Based on parallax measurements obtained during the Hipparcos mission, it is about 146 light-years (45 parsecs) distant from the Sun.
β Corvi (Latinised to Beta Corvi) is the star's Bayer designation.
In a 1951 publication, Atlas Coeli (Skalnate Pleso Atlas of the Heavens) by Czech astronomer Antonín Bečvář, it bore the name Kraz, whose origin and meaning remain unknown.[12][13][14] In 2016, the IAU organized a Working Group on Star Names (WGSN)[15] to catalog and standardize proper names for stars. The WGSN approved the name Kraz for this star on 1 June 2018 and it is now so included in the List of IAU-approved Star Names.[11]
In Chinese, 軫宿 (Zhěn Sù), meaning Chariot (asterism), refers to an asterism consisting of Beta, Gamma, Epsilon and Delta Corvi.[16] Consequently, Beta Corvi itself is known as 軫宿四 (Zhěn Sù sì, English: the Fourth Star of Chariot).[17]
Beta Corvi has about 3.7 times the Sun's mass and is roughly 206 million years old,[3] which is old enough for a star of this mass to consume the hydrogen at its core and evolve away from the main sequence. The stellar classification is G5 II,[3] with the luminosity class of 'II' indicating this is a bright giant. The effective temperature of the star's outer envelope is about 5,100 K,[3] which produces a yellow hue common to G-type stars.[18]
The measured angular diameter of this star is 3.30 ± 0.17 mas.[7] At an estimated distance of 146 light-years (45 parsecs),[1] this yields a physical size of about 16 times the radius of the Sun.[13][19] Because of the star's mass and radius, it is emitting about 164 times the luminosity of the Sun.[8] The abundance of elements other than hydrogen or helium, what astronomers term metallicity, is similar to the proportions in the Sun.[6]
This is a variable star that ranges in apparent visual magnitude from a low of 2.66 to a high of 2.60.[20]