Lambda Centauri
 Location of λ Centauri (circled) |
|
| Observation data Epoch J2000.0 Equinox J2000.0 |
|
|---|---|
| Constellation | Centaurus |
| Right ascension | 11h 35m 46.88530s[1] |
| Declination | −63° 01′ 11.4313″[1] |
| Apparent magnitude (V) | +3.13[2] |
| Characteristics | |
| Spectral type | B9 III[3][4] |
| U−B color index | −0.19[2] |
| B−V color index | −0.04[2] |
| Astrometry | |
| Radial velocity (Rv) | −1.4[5] km/s |
| Proper motion (μ) | RA: −33.41[1] mas/yr Dec.: −7.08[1] mas/yr |
| Parallax (π) | 7.77 ± 0.34[1] mas |
| Distance | 420 ± 20 ly (129 ± 6 pc) |
| Details | |
| Mass | 5.1 M☉ |
| Radius | 11.6[6] R☉ |
| Luminosity | 1094 L☉ |
| Surface gravity (log g) | 3.04 cgs |
| Temperature | 9,880[7] K |
| Rotational velocity (v sin i) | 183[8] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
Lambda Centauri (λ Cen, λ Centauri) is a star in the southern circumpolar constellation of Centaurus. It has an apparent visual magnitude of +3.13,[2] which is bright enough to be seen with the naked eye from the southern hemisphere and places it among the brighter members of this constellation. The star is close enough that its distance can be determined directly using the parallax technique, which gives a value of roughly 420 light-years (130 parsecs) from Earth, with a 5% margin of error.[1] Although a putative solitary star, it has a candidate proper motion companion at an angular separation of 0.73 arcseconds along a position angle of 135°.[9] The nebula IC 2944 lies nearby.
λ Centauri is a B-type giant[10] star with a stellar classification of B9 III.[3] (Although it has also been classified as A1 III.)[7] It has about 5.5[6] times the radius of the Sun and is rotating rapidly with a projected rotational velocity of 183 km s−1.[8] The star's outer atmosphere has an effective temperature of 9,880 K,[7] giving it a blue-white hue.
Based upon the position and movement of this star through space, it is a likely member of the Gould Belt. In particular, it belongs to the Lower Centaurus-Crux (LCC) group of the Scorpius-Centaurus Association, which is the nearest OB association to the Sun. This is a loose grouping of stars that share a common motion through space and therefore formed in the same molecular cloud. The LCC group has an estimated age of 16–20 million years and is centered on a mean distance of 380 light-years (120 parsecs) from Earth.[11]
References
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