Location of κ Sagittarii (circled) | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Sagittarius |
| Right ascension | 20 23 53.17666 |
| Declination | −42° 25′ 22.3376″ |
| Apparent magnitude (V) | +5.64 (6.04 + 7.12) |
| Characteristics | |
| Spectral type | A5 V (A1 + A6) |
| U−B color index | +0.099 |
| B−V color index | +0.192 |
| Astrometry | |
| Radial velocity (Rv) | +2.6 km/s |
| Proper motion (μ) | RA: −13.07 mas/yr Dec.: +13.64 mas/yr |
| Parallax (π) | 10.47 ± 0.50 mas |
| Distance | 310 ± 10 ly (96 ± 5 pc) |
| Absolute magnitude (MV) | 1.03/2.35 |
| Orbit | |
| Period (P) | 700 yr |
| Semi-major axis (a) | 2.032″ |
| Eccentricity (e) | 0.401 |
| Inclination (i) | 80° |
| Longitude of the node (Ω) | 40.7° |
| Periastron epoch (T) | 1912.00 |
| Argument of periastron (ω) (secondary) | 177.3° |
| Details | |
| κ Sgr A | |
| Mass | 1.85 M☉ |
| Luminosity | 38 L☉ |
| Surface gravity (log g) | 4.03 cgs |
| Temperature | 7,990±272 K |
| Age | 833 Myr |
| Other designations | |
| κ Sgr, CD−42° 14847, HD 193807, HIP 100591, HR 7787, SAO 230184, WDS J20239-4225 | |
| Database references | |
| SIMBAD | data |
Kappa Sagittarii (κ Sagittarii) is a binary star system in the zodiac constellation of Sagittarius. It is visible to the naked eye with a combined apparent visual magnitude of +5.64. Based upon an annual parallax shift of 10.47 mas as seen from Earth, this system is located around 310 light years from the Sun. They are receding with a radial velocity of +2.6 km/s.
This is a visual binary system with the components orbiting each other over a period of roughly 700 years, having an eccentricity of 0.4 and a semimajor axis of 2 arc seconds. The pair have a combined spectral type that matches an A-type main sequence star with a stellar classification of A5 V. The individual components are of estimated types A1 and A6. The primary member, component A, is a magnitude 6.04 star with 1.85 times the mass of the Sun. It is radiating 38 times the Sun's luminosity from its photosphere at an effective temperature of about 7,990 K. The companion, component B, is visual magnitude 7.12.
There are two visual companions: component C is a magnitude 14.3 star at an angular separation of 18.6 arc seconds along a position angle of 266°, as of 2000; component D is magnitude 14.0 with a separation of 29.8 arc seconds along a position angle of 219°, also as of 2000.
References
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- ^ Cousins, A. W. J. (1983), "UBV photometry of E region standard stars of intermediate brightness", South African Astronomical Observatory Circular, 7 (7): 36–46, Bibcode:1983SAAOC...7...36C.
- ^ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
- ^ Houk, Nancy (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 2, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1978mcts.book.....H.
- ^ Cvetkovic, Z.; Ninkovic, S. (2010), "On the Component Masses of Visual Binaries", Serbian Astronomical Journal, 180 (180): 71–80, Bibcode:2010SerAJ.180...71C, doi:10.2298/SAJ1080071C.
- ^ Evans, D. S. (June 20–24, 1966), "The Revision of the General Catalogue of Radial Velocities", in Batten, Alan Henry; Heard, John Frederick (eds.), Determination of Radial Velocities and their Applications, Proceedings of IAU Symposium no. 30, vol. 30, University of Toronto: International Astronomical Union, p. 57, Bibcode:1967IAUS...30...57E
- ^ Seymour, Diana M.; et al. (February 2002), "Binary Star Orbits. II. Preliminary First Orbits for 117 Systems", The Astronomical Journal, 123 (2): 1023–1038, Bibcode:2002AJ....123.1023S, doi:10.1086/338441, S2CID 122326479.
- ^ David, Trevor J.; Hillenbrand, Lynne A. (2015), "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets", The Astrophysical Journal, 804 (2): 146, arXiv:1501.03154, Bibcode:2015ApJ...804..146D, doi:10.1088/0004-637X/804/2/146, S2CID 33401607.
- ^ McDonald, I.; et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society, 427 (1): 343–57, arXiv:1208.2037, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x, S2CID 118665352.
- "kappa02 Sgr". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-07-06.
{{cite web}}: CS1 maint: postscript (link) - Mason, B. D.; et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal, 122 (6): 3466–3471, Bibcode:2001AJ....122.3466M, doi:10.1086/323920, retrieved 2015-07-22.
