| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) |
|
|---|---|
| Constellation | Lacerta |
| Right ascension | 22h 31m 17.5010s[1] |
| Declination | +50° 16′ 56.969″[1] |
| Apparent magnitude (V) | 3.777[1] |
| Characteristics | |
| Spectral type | A1 V[1] |
| U−B color index | 0.00[2] |
| B−V color index | +0.01[2] |
| R−I color index | −0.03[2] |
| Astrometry | |
| Radial velocity (Rv) | −4.0 ± 2[1] km/s |
| Proper motion (μ) | RA: 137.22[1] mas/yr Dec.: 17.15[1] mas/yr |
| Parallax (π) | 31.86 ± 0.54[1] mas |
| Distance | 102 ± 2 ly (31.4 ± 0.5 pc) |
| Absolute magnitude (MV) | 1.29[3] |
| Details | |
| Mass | ~2[4] M☉ |
| Radius | 2.143 ± 0.074[5] R☉ |
| Luminosity | 28.552 ± 0.678[5] L☉ |
| Luminosity (bolometric) | 27[4] L☉ |
| Temperature | 9131 ± 167[5] K |
| Rotational velocity (v sin i) | 146[2] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
Alpha Lacertae (Alpha Lac, α Lacertae, α Lac) is an A-type main sequence star in the constellation of Lacerta.[1] It is the brightest star in Lacerta and has an apparent visual magnitude of approximately 3.777.[1][4]
The star has a visual companion, CCDM J22313+5017B, of spectral type A and apparent visual magnitude 11.8, approximately 36 arcseconds away.[6] The companion is optical, a chance line-of-sight coincidence.[2]
Naming [edit]
In Chinese, 螣蛇 (Téng Shé), meaning Flying Serpent, refers to an asterism consisting of α Lacertae, 4 Lacertae, π2 Cygni, π1 Cygni, HD 206267, ε Cephei, β Lacertae, σ Cassiopeiae, ρ Cassiopeiae, τ Cassiopeiae, AR Cassiopeiae, 9 Lacertae, 3 Andromedae, 7 Andromedae, 8 Andromedae, λ Andromedae, κ Andromedae, ι Andromedae, and ψ Andromedae. Consequently, α Lacertae itself is known as 螣蛇一 (Téng Shé yī, English: the First Star of Flying Serpent)[7]
References [edit]
- ^ a b c d e f g h i j k * alf Lac -- Star in double system, database entry, SIMBAD. Accessed on line September 3, 2008.
- ^ a b c d e HR 8585, database entry, The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version), D. Hoffleit and W. H. Warren, Jr., CDS ID V/50. Accessed on line September 3, 2008.
- ^ From apparent magnitude and parallax.
- ^ a b c Alpha Lac, Jim Kaler, Stars. Accessed on line September 3, 2008.
- ^ a b c 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.
- ^ a b Entry 22313+5017, discoverer code BU 703, The Washington Double Star Catalog, United States Naval Observatory. Accessed on line September 3, 2008.
- ^ (Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 7 日
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