Lambda Boötis
| Observation data Epoch J2000.0 Equinox J2000.0 |
|
|---|---|
| Constellation | Boötes |
| Right ascension | 14h 16m 23.019s |
| Declination | +46° 05′ 17.90″ |
| Apparent magnitude (V) | +4.18 |
| Characteristics | |
| Spectral type | A0p |
| Astrometry | |
| Proper motion (μ) |
RA: −187.33±0.14 mas/yr Dec.: 159.05±0.11 mas/yr |
| Parallax (π) | 32.94 ± 0.16mas |
| Distance | 99.0 ± 0.5 ly (30.4 ± 0.1 pc) |
| 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 (λ Boo, λ Boötis) is a star in the constellation Boötes.
Lambda Boötis is a white A-type main sequence dwarf with an apparent magnitude of +4.18. It is approximately 99 light-years from Earth. Lambda Boötis 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.
This star, along with the Aselli (θ Boo, ι Boo and κ Boo), were Al Aulād al Dhiʼbah (ألعولد ألذعب - al aulād al dhiʼb), "the Whelps of the Hyenas".
Al Aulād al Dhiʼbah or Aulad al Thiba was the title of this star in the catalogue of stars in Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars.
In Chinese astronomy, Lambda Boötis is called 玄戈, Pinyin: Xuángē, meaning Sombre Lance, because this star is marking itself and stand alone in Sombre Lance asterism, Purple Forbidden enclosure (see : Chinese constellation). 玄戈 (Xuángē) westernized into Heuen Ko, but the name Heuen Ko was designated for γ Boötis (Seginus) by R.H. Allen, with the meaning is "the heavenly spear"
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