Lambda Librae
λ Librae (Latinised as Lambda Librae) is the Bayer designation for a binary star system in the zodiac constellation of Libra. It can be faintly seen with the naked eye, having an apparent visual magnitude of 5.03. With an annual parallax shift of 10.54 mas, it is roughly 310 light years from the Sun. At that distance, the visual magnitude of this system is diminished by an extinction factor of 0.22 due to interstellar dust. It is 0.1 degree north of the ecliptic.
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Libra |
| Right ascension | 15h 53m 20.05463s |
| Declination | −20° 10′ 01.4177″ |
| Apparent magnitude (V) | 5.03 |
| Characteristics | |
| Spectral type | B3 V |
| U−B color index | −0.584 |
| B−V color index | −0.023 |
| Variable type | Rotating ellipsoidal |
| Astrometry | |
| Radial velocity (Rv) | −2.0±0.5 km/s |
| Proper motion (μ) | RA: −9.81 mas/yr Dec.: −26.85 mas/yr |
| Parallax (π) | 10.54 ± 0.91 mas |
| Distance | 310 ± 30 ly (95 ± 8 pc) |
| Absolute magnitude (MV) | 0.56 |
| Orbit | |
| Period (P) | 14.4829±0.0004 d |
| Eccentricity (e) | 0.27±0.09 |
| Periastron epoch (T) | 2435172.380 ± 0.664 JD |
| Argument of periastron (ω) (secondary) | 217±17° |
| Semi-amplitude (K1) (primary) | 28.5±3.3 km/s |
| Details | |
| Mass | 5.01±0.26 M☉ |
| Radius | 3.9 R☉ |
| Luminosity | 743 L☉ |
| Surface gravity (log g) | 4.75 cgs |
| Temperature | 18,700 K |
| Metallicity [Fe/H] | −0.27 dex |
| Rotational velocity (v sin i) | 155 km/s |
| Age | 282 Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is a single-lined spectroscopic binary star system with an orbital period of 14.48 days and an eccentricity of 0.27. The visible component is a B-type main sequence star with a stellar classification of B3 V. It is a helium-weak chemically peculiar star and a rotating ellipsoidal variable. The star has an estimated 3.9 times the radius of the Sun and five times the Sun's mass. This is a candidate Vega-like star, meaning that it shows an infrared excess characteristic of a circumstellar debris disk. The system is a source of X-ray emission.