Lambda Crucis
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Crux |
| Right ascension | 12h 54m 39.18258s |
| Declination | −59° 08′ 48.1229″ |
| Apparent magnitude (V) | 4.62 |
| Characteristics | |
| Evolutionary stage | main sequence |
| Spectral type | B4 Vne |
| U−B color index | −0.60 |
| B−V color index | −0.15 |
| Variable type | β Cep? |
| Astrometry | |
| Radial velocity (Rv) | +12.0±4.2 km/s |
| Proper motion (μ) | RA: −32.92 mas/yr Dec.: −14.60 mas/yr |
| Parallax (π) | 8.50±0.21 mas |
| Distance | 384 ± 9 ly (118 ± 3 pc) |
| Absolute magnitude (MV) | −1.2 |
| Details | |
| Mass | 5.0±0.1 M☉ |
| Radius | 3.00 R☉ |
| Luminosity | 790 L☉ |
| Surface gravity (log g) | 3.01 cgs |
| Temperature | 16,500 K |
| Rotational velocity (v sin i) | 290 km/s |
| Age | 53.3±8.1 Myr |
| Other designations | |
| λ Cru, Lambda Cru, CD−58°4794, HD 112078, HIP 63007, HR 4897, SAO 240368 | |
| Database references | |
| SIMBAD | data |
λ Crucis, Latinized as Lambda Crucis, is a single, variable star in the southern constellation Crux, near the constellation border with Centaurus. It is visible to the naked eye as a faint, blue-white hued point of light with an apparent visual magnitude that fluctuates around 4.62. The star is located approximately 384 light-years distant from the Sun based on parallax, and is drifting further away with a radial velocity of +12 km/s. It is a proper motion member of the Lower Centaurus–Crux sub-group in the Scorpius–Centaurus OB association, the nearest such association of co-moving massive stars to the Sun.
λ Crucis is listed in the General Catalogue of Variable Stars as a possible β Cephei-type variable. Its brightness varies with an amplitude of 0m.02 over a period of 0.3951 days. However, it is currently thought more likely to be a different type of variable, possibly a λ Eridani variable or rotating ellipsoidal variable.
This object is a B-type main-sequence star with a stellar classification of B4 Vne, where the suffix notation indicates "nebulous" (broad) lines due to rapid rotation, along with emission lines from circumstellar material, making it a Be star. It is around 53 million years old and is spinning rapidly with a projected rotational velocity of 341 km/s. The star has five times the mass of the Sun and about 3.0 times the Sun's radius. It is radiating 790 times the luminosity of the Sun from its photosphere at an effective temperature of 16,500 K.