Kappa Doradus

Kappa Doradus, Latinized from κ Doradus, is a solitary star^[16] located in the southern constellation Dorado. It is faintly visible to the naked eye as a white-hued point of light with an apparent magnitude of 5.28.^[2] The object is located relatively close at a distance of 220 light-years based on Gaia DR3 parallax measurements^[1] and its distance from the Solar System is not changing, having a somewhat constrained heliocentric radial velocity of 0.00 km/s.^[6] At its current distance, Kappa Doradus' brightness is diminished by two-tenths of a magnitude due to interstellar extinction^[17] and it has an absolute magnitude of +1.15.^[7]

κ Doradus

Location of κ Doradus on the map (circled)
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Dorado
Right ascension	04h 44m 21.17834s[1]
Declination	−59° 43′ 57.8563″[1]
Apparent magnitude (V)	5.28[2] (5.27 - 5.30)[3]
Characteristics
Spectral type	A8 IV[4]
B−V color index	+0.20[5]
Variable type	suspected δ Scuti[3]
Astrometry
Radial velocity (Rv)	0.00±3.70[6] km/s
Proper motion (μ)	RA: +23.860 mas/yr[1] Dec.: +39.974 mas/yr[1]
Parallax (π)	14.8207 ± 0.0795 mas[1]
Distance	220 ± 1 ly (67.5 ± 0.4 pc)
Absolute magnitude (MV)	+1.15[7]
Details
Mass	1.78+0.36 −0.20[8] M☉
Radius	2.88+0.21 −0.19[9] R☉
Luminosity	26.6[10] L☉
Surface gravity (log g)	3.79±0.08[9] cgs
Temperature	7,623±123[11] K
Metallicity [Fe/H]	−0.18[12] dex
Rotational velocity (v sin i)	230[13] km/s
Other designations
κ Dor, 12 G. Doradus[14], NSV 16162, CPD−59°376, FK5 2354, GC 5810, HD 30478, HIP 22040, HR 1530, SAO 233664, TIC 220414802[15]
Database references
SIMBAD	data

The object has been given many different classes. Houk & Cowley (1975) gave a class of A8/9 III/IV,^[18] indicating that it is an evolved A-type star with the characteristics of an A8 and A9 star and the blended luminosity class of a giant star and a subgiant. It has also been given a class of A8 IV and A5 III,^[4][19] indicating either a slightly evolved subgiant or an evolved giant star. Kappa Doradus has 1.78 times the mass of the Sun^[8] and 2.88 times the radius of the Sun.^[9] However, this is only its polar radius, as it has an equatorial bulge 26% greater than its polar radius.^[20] It radiates 26.6 times the luminosity of the Sun^[10] from its photosphere at an effective temperature of 7,623 K.^[11] Kappa Doradus is metal deficient with an iron abundance 66.1% of the Sun's or [Fe/H] = −0.18.^[12] Like many hot stars it spins rapidly, having a projected rotational velocity of 230 km/s,^[13] which causes the aforementioned oblation.^[20]

Kappa Doradus variability was first observed in 1981 by astronomer H. M. Matizen.^[21] In the paper, it is used as a comparison star for Alpha Doradus. Matizen found out that Kappa Doradus show Delta Scuti-like amplitudes of 0.03 magnitudes in the visual passband within hours.^[3] As of 2004 however, it has not been confirmed to be variable.^[22]

References

1. Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
2. Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (March 2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H. ISSN 0004-6361. S2CID 17128864.
3. Samus’, N. N.; Kazarovets, E. V.; Durlevich, O. V.; Kireeva, N. N.; Pastukhova, E. N. (January 2017). "General catalogue of variable stars: Version GCVS 5.1". Astronomy Reports. 61 (1): 80–88. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085. eISSN 1562-6881. ISSN 1063-7729. S2CID 125853869.
4. Gray, R. O.; Garrison, R. F. (July 1989). "The late A-type stars - Refined MK classification, confrontation with Stromgren photometry, and the effects of rotation". The Astrophysical Journal Supplement Series. 70: 623. Bibcode:1989ApJS...70..623G. doi:10.1086/191349. eISSN 1538-4365. ISSN 0067-0049. S2CID 121737313.
5. Lake, R. (1965). "Photometric Magnitudes and Colours for Bright Southern Stars (Sixth List)". Monthly Notes of the Astronomical Society of South Africa. 24: 41. Bibcode:1965MNSSA..24...41L. ISSN 0024-8266.
6. Kharchenko, N.V.; Scholz, R.-D.; Piskunov, A.E.; Röser, S.; Schilbach, E. (November 2007). "Astrophysical supplements to the ASCC-2.5: Ia. Radial velocities of ~55000 stars and mean radial velocities of 516 Galactic open clusters and associations". Astronomische Nachrichten. 328 (9): 889–896. arXiv:0705.0878. Bibcode:2007AN....328..889K. doi:10.1002/asna.200710776. eISSN 1521-3994. ISSN 0004-6337. S2CID 119323941.
7. Anderson, E.; Francis, Ch. (May 2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331–346. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. eISSN 1562-6873. ISSN 1063-7737. S2CID 119257644.
8. Stassun, Keivan G.; et al. (9 September 2019). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal. 158 (4): 138. arXiv:1905.10694. Bibcode:2019AJ....158..138S. doi:10.3847/1538-3881/ab3467. eISSN 1538-3881. hdl:1721.1/124721. S2CID 166227927.
9. Allende Prieto, C.; Lambert, D. L. (December 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. ISSN 0004-6361. S2CID 13365201.
10. McDonald, I.; Zijlstra, A. A.; Boyer, M. L. (21 November 2012). "Fundamental parameters and infrared excesses of Hipparcos stars: Parameters and IR excesses from Hipparcos". Monthly Notices of the Royal Astronomical Society. 427 (1): 343–357. arXiv:1208.2037. Bibcode:2012MNRAS.427..343M. doi:10.1111/j.1365-2966.2012.21873.x. eISSN 1365-2966. ISSN 0035-8711. S2CID 118665352.
11. Paunzen, E.; Schnell, A.; Maitzen, H. M. (October 2006). "An empirical temperature calibration for the Δa photometric system II: The A-type and mid F-type stars". Astronomy & Astrophysics. 458 (1): 293–296. arXiv:astro-ph/0607567. Bibcode:2006A&A...458..293P. doi:10.1051/0004-6361:20064889. eISSN 1432-0746. ISSN 0004-6361. S2CID 18219735.
12. Anders, F.; et al. (August 2019). "Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18". Astronomy & Astrophysics. 628: A94. arXiv:1904.11302. Bibcode:2019A&A...628A..94A. doi:10.1051/0004-6361/201935765. eISSN 1432-0746. ISSN 0004-6361. S2CID 131780028.
13. Huang, Su-Shu (September 1953). "A Statistical Study of the Rotation of the Stars". The Astrophysical Journal. 118: 285. Bibcode:1953ApJ...118..285H. doi:10.1086/145751. eISSN 1538-4357. ISSN 0004-637X. S2CID 120328179.
14. Gould, Benjamin Apthorp (1878). "Uranometria Argentina : brillantez y posicion de las estrellas fijas, hasta la septima magnitud, comprendidas dentro de cien grados del polo austral : con atlas". Resultados del Observatorio Nacional Argentino. 1. Bibcode:1879RNAO....1.....G.
15. "* kap Dor". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved September 3, 2023.
16. Eggleton, P. P.; Tokovinin, A. A. (11 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. eISSN 1365-2966. ISSN 0035-8711. S2CID 14878976.
17. Gontcharov, George A.; Mosenkov, Aleksandr V. (28 September 2017). "Verifying reddening and extinction for Gaia DR1 TGAS main sequence stars". Monthly Notices of the Royal Astronomical Society. 472 (4): 3805–3820. arXiv:1709.01160. Bibcode:2017MNRAS.472.3805G. doi:10.1093/mnras/stx2219. eISSN 1365-2966. ISSN 0035-8711. S2CID 118879856.
18. Houk, N.; Cowley, A. P. (1975). University of Michigan Catalogue of two-dimensional spectral types for the HD stars: Declinations −90° to −53°. Vol. 1. Bibcode:1975mcts.book.....H.
19. Abt, Helmut A.; Morrell, Nidia I. (July 1995). "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars". The Astrophysical Journal Supplement Series. 99: 135. Bibcode:1995ApJS...99..135A. doi:10.1086/192182. ISSN 0067-0049. S2CID 120495962.
20. van Belle, Gerard T. (14 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. eISSN 1432-0754. ISSN 0935-4956. S2CID 253689867.
21. Maitzen, H. M. (April 1981). "Variability of the Extreme Silicon Star alpha Dor = HD 29305". Information Bulletin on Variable Stars. 1950: 1. Bibcode:1981IBVS.1950....1M. ISSN 0374-0676.
22. Samus, N. N.; Durlevich, O. V. (November 2004). "VizieR Online Data Catalog: Combined General Catalogue of Variable Stars (Samus+ 2004)". VizieR Online Data Catalog: II/250. Bibcode:2004yCat.2250....0S.