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Lambda Coronae Australis
Observation data
Epoch J2000       Equinox J2000
Constellation Corona Australis
Right ascension 18h 43m 46.94143s [1]
Declination −38° 19′ 24.3941″ [1]
Apparent magnitude (V) 5.11 [2] + 10.01 [3]
Characteristics
Spectral type A0/1V [4] + K0 [5]
B−V color index +0.075±0.002 [6]
Astrometry
Radial velocity (Rv)−26.40±4.2 [7] km/s
Proper motion (μ) RA: +1.047 [1]  mas/ yr
Dec.: −53.774 [1]  mas/ yr
Parallax (π)15.8771 ± 0.2823  mas [1]
Distance205 ± 4  ly
(63 ± 1  pc)
Absolute magnitude (MV)1.15 [2]
Details
λ CrA A
Mass2.17±0.10 [2]  M☉
Radius2.24 [2]  R☉
Luminosity31.25 [6]  L☉
Surface gravity (log g)4.08±0.08 [2]  cgs
Temperature8,609 [8]  K
Metallicity [Fe/H]−0.30 [8]  dex
Rotational velocity (v sin i)148.6±1.6 [9] km/s
Age273 [10]  Myr
Other designations
λ CrA, CD−38°13036, HD 172777, HIP 91875, HR 7021, SAO 210501, WDS J18438-3819A [11]
Database references
SIMBAD data

λ Coronae Australis, Latinized as Lambda Coronae Australis is a binary star [5] system located in the southern constellation of Corona Australis. It is visible to the naked eye as a faint, white-hued point of light with an apparent visual magnitude of 5.11. [2] The system is located at a distance of 205  light-years, based on parallax, [1] and is drifting further away with a radial velocity of −26 km/s. [7]

The primary member of this system, designated component A, is an A-type main-sequence star with a stellar classification of A0/1V. [4] It is 273 [10] million years old and is spinning with a projected rotational velocity of 149 km/s. [9] This high rotation rate is producing an equatorial bulge that is 7% larger than the polar radius. [12] It has 2.17 times the mass of the Sun and 2.24 times the Sun's radius. [2] The star is radiating 31 [6] times the Sun's luminosity from its photosphere at an effective temperature of 8,609 K. [8]

The secondary companion, component B, [13] has an apparent visual magnitude of 10.01 [3] and a class of K0. [5] As of 2016, it has an angular separation of 29.5 ″ from the primary along a position angle of 213°. [3] Component C [14] is a visual companion of magnitude 9.9 and separation 43.3″ from the primary. [3]

References

  1. ^ a b c d e f Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv: 1804.09365. Bibcode: 2018A&A...616A...1G. doi: 10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  2. ^ a b c d e f g Allende Prieto, C.; Lambert, D. L. (1999). "Fundamental parameters of nearby stars from the comparison with evolutionary calculations: masses, radii and effective temperatures". Astronomy and Astrophysics. 352: 555–562. arXiv: astro-ph/9911002. Bibcode: 1999A&A...352..555A.
  3. ^ a b c d Mason, B. D.; et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal, 122 (6): 3466, Bibcode: 2001AJ....122.3466M, doi: 10.1086/323920, retrieved 2015-07-22
  4. ^ a b Houk, N.; Smith-Moore, M. (1988). Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars. Vol. 4. Ann Arbor, MI: Department of Astronomy, University of Michigan. Bibcode: 1988mcts.book.....H.
  5. ^ a b c Eggleton, P. P.; Tokovinin, A. A. (September 2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society. 389 (2): 869–879. arXiv: 0806.2878. Bibcode: 2008MNRAS.389..869E. doi: 10.1111/j.1365-2966.2008.13596.x. S2CID  14878976.
  6. ^ a b c Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv: 1108.4971. Bibcode: 2012AstL...38..331A. doi: 10.1134/S1063773712050015. S2CID  119257644.
  7. ^ a b 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: 1606.08053. Bibcode: 2006AstL...32..759G. doi: 10.1134/S1063773706110065. S2CID  119231169.
  8. ^ a b c Erspamer, D.; North, P. (2003). "Automated spectroscopic abundances of a and F-type stars using echelle spectrographs. II. Abundances of 140 A-F stars from ELODIE". Astronomy and Astrophysics. 398 (3): 1121–1136. arXiv: astro-ph/0210065. Bibcode: 2003A&A...398.1121E. doi: 10.1051/0004-6361:20021711. S2CID  1109164.
  9. ^ a b Díaz, C. G.; et al. (July 2011). "Accurate stellar rotational velocities using the Fourier transform of the cross correlation maximum". Astronomy & Astrophysics. 531: A143. arXiv: 1012.4858. Bibcode: 2011A&A...531A.143D. doi: 10.1051/0004-6361/201016386. S2CID  119286673.
  10. ^ a b David, Trevor J.; Hillenbrand, Lynne A. (2015). "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets". The Astrophysical Journal. 804 (2): 146. arXiv: 1501.03154. Bibcode: 2015ApJ...804..146D. doi: 10.1088/0004-637X/804/2/146. S2CID  33401607.
  11. ^ "lam CrA". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-09-16.
  12. ^ van Belle, Gerard T. (March 2012). "Interferometric observations of rapidly rotating stars". The Astronomy and Astrophysics Review. 20 (1): 51. arXiv: 1204.2572. Bibcode: 2012A&ARv..20...51V. doi: 10.1007/s00159-012-0051-2. S2CID  119273474.
  13. ^ "CD-38 13036B". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-09-16.
  14. ^ "CD-38 13036C". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-09-16.
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