Astronomy:Delta Coronae Australis

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Short description: Star in the constellation Corona Australis
Delta Coronae Australis
Observation data
Equinox J2000.0]] (ICRS)
Constellation Corona Australis
Right ascension  19h 08m 20.96980s[1]
Declination −40° 29′ 48.1155″[1]
Apparent magnitude (V) 4.57[2]
Characteristics
Evolutionary stage horizontal branch[3]
Spectral type K1III[4]
B−V color index +1.070±0.052[2]
Astrometry
Radial velocity (Rv)+21.24±0.19[1] km/s
Proper motion (μ) RA: +47.344[1] mas/yr
Dec.: −27.047[1] mas/yr
Parallax (π)18.6963 ± 0.3123[1] mas
Distance174 ± 3 ly
(53.5 ± 0.9 pc)
Absolute magnitude (MV)0.93[5]
Details
Mass1.50±0.01[3] M
Radius11.37+0.23
−0.65
[1] R
Luminosity54.7±1.1[1] L
Surface gravity (log g)2.59±0.10[3] cgs
Temperature4,654+139
−45
[1] K
Metallicity [Fe/H]+0.01±0.10[3] dex
Age2.80±0.13[3] Gyr
Other designations
δ CrA, CD−40°13061, HD 177873, HIP 94005, HR 7242, SAO 229513[6]
Database references
SIMBADdata

Delta Coronae Australis is a single[7] star located in the southern constellation of Corona Australis. It is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 4.57.[2] The star is located about 174 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +21 km/s.[1]

This object is an evolved giant star with a stellar classification of K1III.[4] After exhausting the supply of hydrogen at its core, the star expanded off the main sequence and now has 11[1] times the radius of the Sun. It is a red clump giant,[3][5] which indicates it is on the horizontal branch and is generating energy through core helium fusion. The star is 2.8[3] billion years old with 1.5[3] times the mass of the Sun. It is radiating 55[1] times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,654 K.[1]

References

  1. 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode2018A&A...616A...1G.  Gaia DR2 record for this source at VizieR.
  2. 2.0 2.1 2.2 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode2012AstL...38..331A. 
  3. 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 Gallenne, A. et al. (August 2018). "Fundamental properties of red-clump stars from long-baseline H-band interferometry". Astronomy & Astrophysics 616: 12. doi:10.1051/0004-6361/201833341. A68. Bibcode2018A&A...616A..68G. 
  4. 4.0 4.1 Houk, Nancy (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, 2, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode1978mcts.book.....H. 
  5. 5.0 5.1 Liu, Y. J. et al. (2007). "The abundances of nearby red clump giants". Monthly Notices of the Royal Astronomical Society 382 (2): 553–66. doi:10.1111/j.1365-2966.2007.11852.x. Bibcode2007MNRAS.382..553L. 
  6. "del CrA". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=del+CrA. 
  7. Eggleton, P. P.; Tokovinin, A. A. (2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society 389 (2): 869. doi:10.1111/j.1365-2966.2008.13596.x. Bibcode2008MNRAS.389..869E.