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) | 4.82 |
| Details | |
| Radius | 1.431 ± 0.023[1] R☉ |
| Luminosity | 3.461 ± 0.042[1] L☉ |
| Temperature | 6,594 ± 55[1] K |
| Age | 1.7[2] 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.[3] Consequently, σ Boötis itself is known as 梗河二 (Gěng Hé èr, English: the Second Star of Celestial Lance.)[4]
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.
References
- 1 2 3 Boyajian, Tabetha S.; et al. (February 2012), "Stellar Diameters and Temperatures. I. Main-sequence A, F, and G Stars", The Astrophysical Journal 746 (1): 101, arXiv:1112.3316, Bibcode:2012ApJ...746..101B, doi:10.1088/0004-637X/746/1/101. See Table 10.
- ↑ Decin, G.; et al. (November 2003), "Age Dependence of the Vega Phenomenon: Observations", The Astrophysical Journal 598 (1): 636–644, arXiv:astro-ph/0308294, Bibcode:2003ApJ...598..636D, doi:10.1086/378800
- ↑ (Chinese) 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 978-986-7332-25-7.
- ↑ (Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 29 日
External links
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