Lambda Boötis
Lambda Boötis (λ Boötis, abbreviated Lam Boo, λ Boo), also named Xuange (/ˈʃwɛnɡə/), is a star in the northern constellation of Boötes. Based on parallax measurements, it is approximately 99 light-years from the Sun.
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Boötes |
| Right ascension | 14h 16m 23.01880s |
| Declination | +46° 05′ 17.9005″ |
| Apparent magnitude (V) | +4.18 |
| Characteristics | |
| Spectral type | A0p λB |
| U−B color index | +0.05 |
| B−V color index | +0.08 |
| Astrometry | |
| Radial velocity (Rv) | −7.9±1.6 km/s |
| Proper motion (μ) | RA: −187.33±0.14 mas/yr Dec.: 159.05±0.11 mas/yr |
| Parallax (π) | 32.94 ± 0.16 mas |
| Distance | 99.0 ± 0.5 ly (30.4 ± 0.1 pc) |
| Absolute magnitude (MV) | +1.71±0.23 |
| Details | |
| Mass | 1.66+0.19 −0.16 M☉ |
| Radius | 1.7 R☉ |
| Luminosity | 19.1+9.0 −6.1 L☉ |
| Surface gravity (log g) | 4.188 cgs |
| Temperature | 8720 K |
| Rotational velocity (v sin i) | 100 km/s |
| Age | 2.8+1.1 −0.8 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Lambda Boötis is a white A-type main sequence dwarf with an apparent magnitude of +4.18. It is the prototype of a group of rare stars known as Lambda Boötis stars, all of which are dwarf stars with unusually low abundances of metals in their spectra. Its diameter has been directly measured to be 1.7 times that of the Sun.
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