Kappa1 Sagittarii

Kappa1 Sagittarii (κ1 Sagittarii) is a solitary,[11] white-hued star in the zodiac constellation of Sagittarius. It has an apparent visual magnitude of +5.58,[2] which is bright enough to be faintly visible to the naked eye. According to the Bortle scale, it can be viewed from dark suburban skies. Based upon an annual parallax shift of 15.12 mas as seen from Earth,[1] this star is located around 223 light years from the Sun. It is advancing in the general direction of the Sun with a radial velocity of −11.6 km/s.[4]

For other stars with this Bayer designation, see κ Sagittarii.
κ1 Sagittarii
Location of κ1 Sagittarii (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Sagittarius
Right ascension  20h 22m 27.50366s[1]
Declination −42° 02′ 58.3648″[1]
Apparent magnitude (V) +5.58[2]
Characteristics
Spectral type A0 V[3]
U−B color index −0.008[2]
B−V color index +0.004[2]
Astrometry
Radial velocity (Rv)−11.6[4] km/s
Proper motion (μ) RA: +41.312[5] mas/yr
Dec.: −83.742[5] mas/yr
Parallax (π)14.6086 ± 0.1738[5] mas
Distance223 ± 3 ly
(68.5 ± 0.8 pc)
Absolute magnitude (MV)1.47[6]
Details
Mass2.23±0.02[7] M☉
Radius1.7[8] R☉
Luminosity27.5[7] L☉
Surface gravity (log g)4.33[9] cgs
Temperature9,962±339[9] K
Rotational velocity (v sin i)79[3] km/s
Age161[9] Myr
Other designations
κ1 Sgr, CD−42°14836, HD 193571, HIP 100469, HR 7779, SAO 230177, WDS J20225-4203[10]
Database references
SIMBADdata

This is an A-type main sequence star with a stellar classification of A0 V.[3] It displays an infrared excess, with the measured radiation indicating the star is orbited by a two-component debris disk.[8] The star is about 161[9] million years old with 2.23[7] times the mass of the Sun and 1.7[8] times the Sun's radius. It is radiating 27.5 times the Sun's luminosity from its photosphere at an effective temperature of roughly 9,962 K.[9]

There are two visual companions: component B is a magnitude 12.6 star at an angular separation of 39.3 arc seconds along a position angle of 312°, as of 2000; component C is magnitude 11.6 with a separation of 56.8 arc seconds along a position angle of 283°, as of 1999.[12] Neither star is physically associated with Kappa1 Sagittarii.[11]

References
  1. van Leeuwen, F. (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.
  2. Cousins, A. W. J. (1983), "UBV photometry of E region standard stars of intermediate brightness", South African Astronomical Observatory Circular (7): 36–46, Bibcode:1983SAAOC...7...36C.
  3. 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.
  4. Evans, D. S. (June 20–24, 1966), Batten, Alan Henry; Heard, John Frederick (eds.), The Revision of the General Catalogue of Radial Velocities, University of Toronto: International Astronomical Union, Bibcode:1967IAUS...30...57E
  5. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  6. Ammler-von Eiff, M.; Reiners, A. (June 2012), "New measurements of rotation and differential rotation in A-F stars: are there two populations of differentially rotating stars?", Astronomy & Astrophysics, 542: 31, arXiv:1204.2459, Bibcode:2012A&A...542A.116A, doi:10.1051/0004-6361/201118724, A116.
  7. Zorec, J.; Royer, F. (January 2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics, 537: A120, arXiv:1201.2052, Bibcode:2012A&A...537A.120Z, doi:10.1051/0004-6361/201117691.
  8. Patel, Rahul I.; et al. (February 2017), "The Faintest WISE Debris Disks: Enhanced Methods for Detection and Verification", The Astronomical Journal, 153 (2): 19, arXiv:1612.04818, Bibcode:2017AJ....153...54P, doi:10.3847/1538-3881/153/2/54, 54.
  9. 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.
  10. "kappa01 Sgr". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-07-07.
  11. 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.
  12. Mason, B. D.; et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal, 122: 3466–3471, Bibcode:2001AJ....122.3466M, doi:10.1086/323920, retrieved 2015-07-22.
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