Astronomy:Kappa1 Coronae Australis

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Short description: Star in the constellation Corona Australis
κ1 Coronae Australis
Observation data
Epoch J2000.0   Equinox (celestial coordinates)
Constellation Corona Australis
Right ascension  18h 33m 23.0809s[1]
Declination −38° 43′ 12.166″[1]
Apparent magnitude (V) 6.17±0.01[2]
Characteristics
Spectral type A0 IV[3]
B−V color index −0.06[4]
Astrometry
Radial velocity (Rv)−16±3.7[5] km/s
Proper motion (μ) RA: −0.512[1] mas/yr
Dec.: −22.550[1] mas/yr
Parallax (π)4.4833 ± 0.0831[1] mas
Distance730 ± 10 ly
(223 ± 4 pc)
Absolute magnitude (MV)−0.78
Details[6]
Mass2.82±0.38 M
Radius3.79±0.15 R
Luminosity179±14 L
Surface gravity (log g)3.73±0.07 cgs
Temperature11,079[7] K
Metallicity [Fe/H]−0.2[8] dex
Rotational velocity (v sin i)339[9] km/s
Age4.1±1.8[10] Myr
Other designations
κ1 CrA, CD−38°12896, CPD−38°7538, GC 25315, HD 170868, HIP 90969, HR 6952, SAO 210293, 210296, WDS J18334-3844B[11]
Database references
SIMBADdata

Kappa1 Coronae Australis (Kappa1 CrA), Latinized from κ1 Coronae Australis, is a star located in the southern constellation Corona Australis. It has an apparent magnitude of 6.17, placing it near the limit for naked eye visibility.

There has been some disagreement about the object's distance. The New Hipparcos Reduction calculates a parallax of 21.18±6.53 mas,[12] yielding a distance of 154±47 light years, somewhat poorly constrained. New analysis from the Gaia spacecraft find that it has a physical relation to κ2 Coronae Australis.[13] Both of their currently parallaxes place them around 700 light years away.[1] As of 2018, the two stars have an angular separation of 20.5 along a position angle of 359°.[14]

Kappa1 CrA has a stellar classification of A0 IV,[3] indicating that it is a slightly evolved A-type star. At present it has 2.8 times the mass of the Sun and a slightly enlarged radius of 3.79 R.[6] It radiates at 179 times the luminosity of the Sun[6] from its photosphere at an effective temperature of 11,079 K.[7] Kappa1 CrA's metallicity – specifically the iron abundance – is 63% that of the Sun.[8] With an age of about four million years, Kappa1 CrA is modelled to be a young star only about 10% of the way through its main sequence life.[9]

References

  1. 1.0 1.1 1.2 1.3 1.4 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  2. Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P. et al. (March 2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics 355: L27–L30. ISSN 0004-6361. Bibcode2000A&A...355L..27H. 
  3. 3.0 3.1 Pickles, A.; Depagne, É. (December 2010). "All-Sky Spectrally MatchedUBVRI - ZY and ugriz Magnitudes for Stars in the Tycho2 Catalog". Publications of the Astronomical Society of the Pacific 122 (898): 1437–1464. doi:10.1086/657947. ISSN 0004-6280. Bibcode2010PASP..122.1437P. 
  4. Corben, P. M. (1971). "Photoelectric Magnitudes and Colours for Bright Southern Stars". Monthly Notes of the Astronomical Society of South Africa 30: 37. ISSN 0024-8266. Bibcode1971MNSSA..30...37C. 
  5. Kharchenko, N.V.; Scholz, R.-D.; Piskunov, A.E.; Röser, S.; Schilbach, E. (November 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. doi:10.1002/asna.200710776. ISSN 0004-6337. Bibcode2007AN....328..889K. 
  6. 6.0 6.1 6.2 Stassun, Keivan G. et al. (9 September 2019). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal 158 (4): 138. doi:10.3847/1538-3881/ab3467. ISSN 0004-6256. Bibcode2019AJ....158..138S. 
  7. 7.0 7.1 McDonald, I.; Zijlstra, A. A.; Boyer, M. L. (21 November 2012). "Fundamental parameters and infrared excesses of Hipparcos stars: Parameters and IR excesses from Hipparcos". Monthly Notices of the Royal Astronomical Society 427 (1): 343–357. doi:10.1111/j.1365-2966.2012.21873.x. ISSN 0035-8711. Bibcode2012MNRAS.427..343M. 
  8. 8.0 8.1 Anders, F. et al. (February 2022). "Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia EDR3 stars brighter than G = 18.5". Astronomy & Astrophysics 658: A91. doi:10.1051/0004-6361/202142369. ISSN 0004-6361. Bibcode2022A&A...658A..91A. 
  9. 9.0 9.1 Zorec, J.; Royer, F. (January 2012). "Rotational velocities of A-type stars IV: Evolution of rotational velocities". Astronomy & Astrophysics 537: A120. doi:10.1051/0004-6361/201117691. ISSN 0004-6361. Bibcode2012A&A...537A.120Z. 
  10. Tetzlaff, N. et al. (January 2011). "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun". Monthly Notices of the Royal Astronomical Society 410 (1): 190–200. doi:10.1111/j.1365-2966.2010.17434.x. Bibcode2011MNRAS.410..190T. 
  11. "kap01 CrA". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=kap01+CrA. 
  12. van Leeuwen, F. (13 August 2007). "Validation of the new Hipparcos reduction". Astronomy & Astrophysics 474 (2): 653–664. doi:10.1051/0004-6361:20078357. ISSN 0004-6361. Bibcode2007A&A...474..653V. 
  13. Makarov, Valeri V. (2020). "Two-epoch Orbit Estimation for Wide Binaries Resolved in Hipparcos and Gaia". The Astronomical Journal 160 (6): 284. doi:10.3847/1538-3881/abbe1c. Bibcode2020AJ....160..284M. 
  14. Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I.; Douglass, Geoffrey G.; Worley, Charles E. (December 2001). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog". The Astronomical Journal 122 (6): 3466–3471. doi:10.1086/323920. ISSN 0004-6256. Bibcode2001AJ....122.3466M. 
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