HD 171978
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Serpens |
| Right ascension | 18h 37m 35.9613s[1] |
| Declination | −00° 18′ 34.100″[1] |
| Apparent magnitude (V) | 5.74 to 5.86[2] |
| Characteristics | |
| Spectral type | A1V / A1V (spectroscopic binary)[3] |
| U−B color index | +0.06[3] |
| B−V color index | +0.07[3] |
| R−I color index | +0.04[3] |
| Astrometry | |
| Radial velocity (Rv) | 11.4[3][4] km/s |
| Proper motion (μ) | RA: 11.74[1] mas/yr Dec.: −19.83[1] mas/yr |
| Parallax (π) | 5.06 ± 0.93 mas[1] |
| Distance | approx. 600 ly (approx. 200 pc) |
| Absolute magnitude (MV) | −0.7[5] |
| Other designations | |
| Database references | |
| SIMBAD | data |
The star HD 171978 is a spectroscopic binary in the constellation of Serpens. It consists of two A-type main sequence stars orbiting each other with a period of approximately 14.7 days.[3] The overall apparent visual magnitude of the system varies between 5.74 and 5.86.[2]
References
- ^ a b c d e f NSV 11122 -- Spectroscopic binary, database entry, SIMBAD. Accessed on line October 3, 2008.
- ^ a b NSV 11122, database entry, New Catalogue of Suspected Variable Stars, the improved version, Sternberg Astronomical Institute, Moscow, Russia. Accessed on line October 3, 2008.
- ^ a b c d e f HR 6993, 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 October 3, 2008.
- ^ Figure is for the barycenter of the spectroscopic binary system.
- ^ From apparent magnitude and parallax.
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