R Coronae Australis

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R Coronae Australis
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Corona Australis
Right ascension 19h 01m 53.6503s[1]
Declination −36° 57′ 07.87″[1]
Apparent magnitude (V) +11.91
Spectral type B5IIIpe[2]
Variable type INSA[3]
Radial velocity (Rv) -36.0 ± 4.9[4] km/s
Proper motion (μ) RA: -28.30[1] mas/yr
Dec.: 20.57[1] mas/yr
Parallax (π) 40.93 ± 27.95[1] mas
Distance approx. 80 ly
(approx. 20 pc)
Other designations
CD−37° 13027, HIP 93449, Wray 15-1887
Database references

R Coronae Australis (R CrA) is a variable star in the constellation Corona Australis.[2] It has varied between magnitudes 10 and 14.36.[5] A small reflection/emission nebula NGC 6729 extends from the star towards SE.

This star is moving toward the Solar System with a radial velocity of 36 km s−1. In roughly 222,000 years, this system may approach within 1.77 light-years (0.54 parsecs) of the Sun. However, this estimate has a considerable margin of error, so the actual distance remains uncertain.[6]

A colour photo of the R Coronae Australis region in the southern Milky Way.


  1. ^ a b c d e van Leeuwen, F.; et al. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752Freely accessible. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. 
  2. ^ a b "R Coronae Australis". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 29 June 2014. 
  3. ^ Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/gcvs. Originally published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S. 
  4. ^ Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv:1606.08053Freely accessible. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. Retrieved 12 December 2016. 
  5. ^ BSJ (14 June 2010). "R Coronae Australis". AAVSO Website. American Association of Variable Star Observers. Retrieved 29 June 2014. 
  6. ^ Dybczyński, P. A. (April 2006), "Simulating observable comets. III. Real stellar perturbers of the Oort cloud and their output", Astronomy and Astrophysics, 449 (3): 1233–1242, Bibcode:2006A&A...449.1233D, doi:10.1051/0004-6361:20054284