Astronomy:Delta Coronae Australis
  | |
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Corona Australis[1] |
| Right ascension | 19h 08m 20.970s[2] |
| Declination | −40° 29′ 48.113″[2] |
| Apparent magnitude (V) | 4.57[1] |
| Characteristics | |
| Evolutionary stage | horizontal branch[3] |
| Spectral type | K1III[4] |
| B−V color index | +1.070±0.052[1] |
| Astrometry | |
| Radial velocity (Rv) | +21.24±0.19[5] km/s |
| Proper motion (μ) | RA: +47.391[2] mas/yr Dec.: −27.246[2] mas/yr |
| Parallax (π) | 17.6582 ± 0.246[2] mas |
| Distance | 185 ± 3 ly (56.6 ± 0.8 pc) |
| Absolute magnitude (MV) | 0.93[6] |
| Details[3] | |
| Mass | 1.50±0.01 M☉ |
| Radius | 11.25±0.11 R☉ |
| Luminosity | 53±1 L☉ |
| Surface gravity (log g) | 2.59±0.10 cgs |
| Temperature | 4,645±14 K |
| Metallicity [Fe/H] | +0.01±0.10 dex |
| Age | 2.80±0.13 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Delta Coronae Australis, also named Qedty,[8] is a single[9] star located in the southern constellation of Corona Australis. Its Bayer designation is Latinized from δ Coronae Australis, and abbreviated Delta CrA or δ CrA. This body is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 4.57.[1] The star is located at a distance of about 185 light-years (57 pc) from the Sun based on parallax, and is drifting further away with a radial velocity of +21 km/s.[5]
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 11.25 times the radius of the Sun. It is a red clump giant,[3][6] which indicates it is on the horizontal branch and is generating energy through core helium fusion. The star is 2.8 billion years old with 1.5 times the mass of the Sun. It is radiating 53 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,645 K.[3]
This star was part of the ancient Egyptian constellation Qedty, the Two Nets, used in decan star clocks. The IAU Working Group on Star Names adopted the name Qedty for this star on 13 August 2026.[8]
References
- ↑ 1.0 1.1 1.2 1.3 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A XHIP record for this object at VizieR.
- ↑ 2.0 2.1 2.2 2.3 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.
- ↑ 3.0 3.1 3.2 3.3 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. Bibcode: 2018A&A...616A..68G.
- ↑ 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, Bibcode: 1978mcts.book.....H.
- ↑ 5.0 5.1 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. Bibcode: 2018A&A...616A...1G. Gaia DR2 record for this source at VizieR.
- ↑ 6.0 6.1 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. Bibcode: 2007MNRAS.382..553L.
- ↑ "del CrA". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=del+CrA.
- ↑ 8.0 8.1 "IAU Catalog of Star Names". https://exopla.net/star-names/modern-iau-star-names/.
- ↑ 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. Bibcode: 2008MNRAS.389..869E.
 |  |
