Kappa2 Coronae Australis

For other star systems with this Bayer designation see κ Coronae Australis
κ2 Coronae Australis
Location of Kappa2 CrA (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Corona Australis
Right ascension 18h 33m 23.13130s[1]
Declination −38° 43′ 33.5392″[1]
Apparent magnitude (V) 5.59±0.01[2]
Characteristics
Spectral type B9 Vnn[3]
B−V color index −0.06[4]
Astrometry
Radial velocity (Rv)−15.0±7.4[5] km/s
Proper motion (μ) RA: −2.911 mas/yr[1]
Dec.: −20.468 mas/yr[1]
Parallax (π)4.6115 ± 0.0747 mas[1]
Distance710 ± 10 ly
(217 ± 4 pc)
Details
Mass3.12+0.41
−0.37[6] M☉
Radius5.28±0.28[7] R☉
Luminosity460[8] L☉
Surface gravity (log g)3.58±0.07[6] cgs
Temperature12,600[9] K
Metallicity [Fe/H]−0.10[10] dex
Other designations
κ2 CrA, 17 G. Coronae Australis[11], CD−38°12895, GC 25314, HD 170868, HIP 90968, HR 6953, SAO 210294, 210295, CCDM J18334-3843A, WDS J18334-3844A[12]
Database references
SIMBADdata

Kappa2 Coronae Australis (Kappa2 CrA), Latinized from κ2 Coronae Australis, is the primary of a probable binary system[13] located in the southern constellation Corona Australis. It is visible to the naked eye as a bluish-white hued star with an apparent visual magnitude of 5.59.[2] The distance to this star is roughly 710 light years based on Gaia DR3 parallax measurements.[1] The radial velocity is poorly constrained, but the star appears to be moving closer with a radial velocity of around −15 km/s.[5] At its current distance, Kappa2 CrA's brightness is diminished by 0.45 magnitudes due to interstellar dust.[14]

This is an ordinary B-type main-sequence star with a stellar classification of B9Vnn, with the nn meaning extremely nebulous absorption lines, usually due to rapid rotation.[3] It has 3.12 times the mass of the Sun[6] and a radius 5.28 times larger than the Sun,[7] which is large for stars of this type. It radiates 460 times the luminosity of the Sun from its photosphere[8] at an effective temperature of 12,600 K.[9] The large radius combined with the high luminosity of the star may indicate that Kappa2 CrA is highly evolved.[citation needed]

Kappa2 CrA forms a binary star with Kappa1 Coronae Australis, also known as HR 6952.[15] Kappa1 is located 20.5" away along a position angle of 359°.[16] The two were once thought to be an optical pair due to the large difference in their parallaxes but are now considered to be physical based on Gaia measurements. The satellite places Kappa1 and Kappa2 around 700 light years away.[1]

  1. ^ a b c d e f Cite error: The named reference GaiaDR3 was invoked but never defined (see the help page).
  2. ^ a b Cite error: The named reference Tycho2000 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference abt1995 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference Corben1971 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Kharchenko2007 was invoked but never defined (see the help page).
  6. ^ a b c Cite error: The named reference Stassun2019 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference Kervella2004 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference McDonald2012 was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference Phillip1980 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Anders2019 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Gould1879 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference Gontcharov2017 was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference valeri2020 was invoked but never defined (see the help page).
  16. ^ Cite error: The named reference Mason2001 was invoked but never defined (see the help page).