Chi1 Sagittarii

Chi1 Sagittarii
Diagram showing star positions and boundaries of the Sagittarius constellation and its surroundings
Location of χ1 Sagittari (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Sagittarius
Right ascension 19h 25m 16.49013s[1]
Declination −24° 30′ 30.8599″[1]
Apparent magnitude (V) +5.03[2] (5.46 + 5.96)[3]
Characteristics
Evolutionary stage main sequence[4]
Spectral type A3/5 IV/V[5] (A2IV + A5IV)
B−V color index +0.23[2]
Astrometry
Radial velocity (Rv)−43.4±1.6[6] km/s
Proper motion (μ) RA: +61.63[1] mas/yr
Dec.: −50.66[1] mas/yr
Parallax (π)13.25±0.07 mas[3]
Distance246 ± 1 ly
(75.5 ± 0.4 pc)
Absolute magnitude (MV)+0.59[7]
Orbit[3]
Period (P)5.6985±0.0015 yr
Semi-major axis (a)0.0664±0.0003″
Eccentricity (e)0.7099±0.0033
Inclination (i)93.02±0.50°
Longitude of the node (Ω)80.15±0.55°
Periastron epoch (T)B 2023.9455±0.0010
Argument of periastron (ω)
(secondary)		354.19±0.75°
Details[3]
Chi1 Sgr A
Mass2.09±0.02 M☉
Chi1 Sgr B
Mass1.78±0.01 M☉
Other designations
Chi1 Sgr, 47 Sgr, CPD−24°6721, HD 182369, HIP 95477, HR 7362, SAO 188101, WDS J19253-2431[8]
Database references
SIMBADdata

Chi1 Sagittarii (χ1 Sagittarii) is a binary star[9] system in the zodiac constellation of Sagittarius. The pair have a combined apparent visual magnitude of +5.03,[2] which is bright enough to be seen with the naked eye. Based upon a parallax of 13.25 mas,[3] it is located around 246 light years away. It is advancing through space in the general direction of the Earth with a radial velocity of −43.4 km/s.[6]

This is a visual binary with an orbital period of 5.6985 years, an eccentricity of 0.710, and an angular semimajor axis of 66.4 mas. The magnitude 5.46 primary, Chi1 Sagittarii A, has a mass 2.09 times that of the Sun, while the secondary, Chi1 Sagittarii B, has a mass 1.78 times solar and a magnitude of 5.96. Spectral types of A2IV and A5IV have been published for the primary and secondary component.[3] A spectrum of A3/5 IV/V has been published,[5] but Helmut Abt published spectral type of kA5hF0VmF0, typical of Am stars.[10] This notation indicates it has the calcium K-lines of an A5 star, and the hydrogen and metal lines of an F0 star.

References

  1. 1 2 3 4 van Leeuwen, Floor. (November 2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. eISSN 1432-0746. ISSN 0004-6361. S2CID 18759600.
  2. 1 2 3 Nicolet, B. (1978), "Photoelectric photometric Catalogue of homogeneous measurements in the UBV System", Astronomy and Astrophysics Supplement Series, 34: 1–49, Bibcode:1978A&AS...34....1N, S2CID 117241083.
  3. 1 2 3 4 5 6 Docobo, José Ángel; Campo, Pedro Pablo; Gómez, Jorge; Piccotti, Luca; Caballero-Valdes, Camila; Mendez, Rene A.; Costa, Edgardo (2026-07-31), "22 Orbits of Binaries Based on SOAR Speckle Observations: Systems with Early Type Components", The Astronomical Journal, 172 (2): 133, doi:10.3847/1538-3881/ae877f, ISSN 0004-6256.
  4. ↑ Zorec, J.; Royer, F. (2012). "Rotational velocities of A-type stars. IV. Evolution of rotational velocities". Astronomy and Astrophysics. 537: A120. arXiv:1201.2052. Bibcode:2012A&A...537A.120Z. doi:10.1051/0004-6361/201117691.
  5. 1 2 Houk, Nancy; Smith-Moore, M. (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 4, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1988mcts.book.....H, S2CID 118097741.
  6. 1 2 Kharchenko, N. V.; Scholz, R.-D.; Piskunov, A. E.; Röser, S.; Schilbach, E. (2007), "Astrophysical supplements to the ASCC-2.5: Ia. Radial velocities of ˜55000 stars and mean radial velocities of 516 Galactic open clusters and associations", Astronomische Nachrichten, 328 (9): 889–896, arXiv:0705.0878, Bibcode:2007AN....328..889K, doi:10.1002/asna.200710776, S2CID 119323941.
  7. ↑ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
  8. ↑ "chi01 Sgr". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-07-05.{{cite web}}: CS1 maint: postscript (link)
  9. ↑ "Sixth Catalog of Orbits of Visual Binary Stars". United States Naval Observatory. April 25, 2016. Archived from the original on 1 August 2017. Retrieved 20 June 2017.
  10. ↑ Abt, H. A. (March 1981), "Visual multiples. VII - MK classifications", Astrophysical Journal Supplement Series, 45: 437–456, Bibcode:1981ApJS...45..437A, doi:10.1086/190719.
  11. 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.
  12. 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.
  13. Royer, F.; et al. (February 2007), "Rotational velocities of A-type stars. III. Velocity distributions", Astronomy and Astrophysics, 463 (2): 671–682, arXiv:astro-ph/0610785, Bibcode:2007A&A...463..671R, doi:10.1051/0004-6361:20065224, S2CID 18475298.
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