Sigma Boötis
| Observation data Epoch J2000 Equinox J2000 |
|
|---|---|
| Constellation | Boötes |
| Right ascension | 14h 34m 40.8171s |
| Declination | +29° 44′ 42.468″ |
| Apparent magnitude (V) | 4.46 |
| Characteristics | |
| Spectral type | F2V |
| U−B color index | -0.08 |
| B−V color index | 0.36 |
| R−I color index | 0.19 |
| Variable type | Variable star |
| Astrometry | |
| Radial velocity (Rv) | 0.2 km/s |
| Proper motion (μ) |
RA: 188.32 mas/yr Dec.: 132.72 mas/yr |
| Parallax (π) | 64.66 ± 0.72 mas |
| Distance | 50.4 ± 0.6 ly (15.5 ± 0.2 pc) |
| Absolute magnitude (MV) | 3.52 |
| Details | |
| Radius | 1.431 ± 0.023 R☉ |
| Luminosity | 3.461 ± 0.042 L☉ |
| Surface gravity (log g) | 4.30 cgs |
| Temperature | 6,594 ± 55 K |
| Age | 1.7 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Data sources: | |
|
Hipparcos Catalogue, CCDM (2002), Bright Star Catalogue (5th rev. ed.) |
|
| Database references | |
| SIMBAD | data |
Sigma Boötis (σ Boo, σ Boötis) is a star in the constellation Boötes.
Sigma Boötis is a yellow-white F-type main sequence dwarf with an apparent magnitude of +4.47. It is approximately 50.4 light years from Earth.
In Chinese, 梗河 (Gěng Hé), meaning Celestial Lance, refers to an asterism consisting of σ Boötis, ε Boötis and ρ Boötis. Consequently, σ Boötis itself is known as 梗河二 (Gěng Hé èr, English: the Second Star of Celestial Lance.)
Located to the southeast of Rho Boötis, the fusing dwarf Sigma may at first appear as a naked-eye double, but the angular proximity with Rho is merely line-of-sight. Like many of its spectral class, Sigma is apparently a variable of the Delta Scuti variety, which vary subtly with multiple periods of hours.
...
Wikipedia