AF Columbae

AF Columbae

A light curve for AF Columbae, plotted from Hipparcos data[1]
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Columba
Right ascension	06^h 10^m 10.40393^s[2]
Declination	−40° 21′ 13.6464″[2]
Apparent magnitude (V)	5.60 - 5.71[3]
Characteristics
Evolutionary stage	AGB[4]
Spectral type	M2 II/III[5]
B−V color index	+1.68[6]
Variable type	Lb[7]
Astrometry
Radial velocity (Rv)	−19±7.4[8] km/s
Proper motion (μ)	RA: −20.650 mas/yr[2] Dec.: +74.080 mas/yr[2]
Parallax (π)	3.9737 ± 0.0841 mas[2]
Distance	820 ± 20 ly (252 ± 5 pc)
Absolute magnitude (MV)	−1.53[9]
Details
Mass	1.54[10] M☉
Radius	148[11] R☉
Luminosity (bolometric)	1,853[12] L☉
Surface gravity (log g)	0.26[13] cgs
Temperature	3,611±122[14] K
Other designations
82 G. Columbae[15], AF Col, NSV 2864, CD−40°2291, CPD−40°930, GC 7873, HD 42682, HIP 29263, HR 2203, SAO 217753[16]
Database references
SIMBAD	data

AF Columbae, also known as HD 42682, is a solitary,[17] red hued variable star located in the southern constellation Columba, the dove. It has an apparent magnitude that fluctuates between 5.6 and 5.71.[3] Nevertheless, it is faintly visible to the naked eye. Parallax measurements from the Gaia spacecraft place the star relatively far at a distance of 820 light years.[2] However, it is approaching the Solar System with a poorly constrained radial velocity of −19 km/s.[8]

AF Columbae is a red giant that is currently on the asymptotic giant branch,[4] generating energy via hydrogen and helium shell burning. It has a stellar classification of M2 II/III,[5] indicating an evolved M-type star with the blended luminosity class of a regular giant star and a bright giant. At present it has 1.54 times the mass of the Sun[10] but has expanded to 148 times its girth.[11] It shines with a bolometric luminosity 1,853 times that of the Sun[12] from its enlarged photosphere at an effective temperature of 3,611 K.[14]

The star was discovered to be a variable star when the Hipparcos data was analyzed. It was given its variable star designation, AF Columbae, in 1999.[18] The object is classified as a slow irregular variable of subtype Lb.[7] Tabur et al. (2009) found 5 periods for AF Columbae. Most of them last for 40-50 days, while one of them last for 112 days.[19] It appears to be a runaway star, having an unusually high peculiar velocity of 93.2+4.6
−5.2 km/s.[20]

References

1. "Light Curve". Hipparcos ESA. ESA. Retrieved 17 February 2022.
2. 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.
3. Kukarkin, B. V.; Kholopov, P. N.; Artiukhina, N. M.; Fedorovich, V. P.; Frolov, M. S.; Goranskij, V. P.; Gorynya, N. A.; Karitskaya, E. A.; Kireeva, N. N.; Kukarkina, N. P.; Kurochkin, N. E.; Medvedeva, G. I.; Perova, N. B.; Ponomareva, G. A.; Samus, N. N.; Shugarov, S. Y. (1981). "Catalogue of suspected variable stars". Moscow: 0. Bibcode:1981CSV...C......0K.
4. Eggen, Olin J. (July 1992). "Asymptotic giant branch stars near the sun". The Astronomical Journal. 104: 275. Bibcode:1992AJ....104..275E. doi:10.1086/116239. ISSN 0004-6256.
5. Houk, Nancy (1978). Michigan catalogue of two-dimensional spectral types for the HD stars Volume II: Declinations −52° to −41°. Bibcode:1978mcts.book.....H.
6. Corben, P. M. (April 1971). "Photoelectric Magnitudes and Colours for Bright Southern Stars". Monthly Notes of the Astronomical Society of South Africa. 30 (4): 37. Bibcode:1971MNSSA..30...37C. ISSN 0024-8266.
7. 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.
8. 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.
9. 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.
10. Kervella, Pierre; Arenou, Frédéric; Mignard, François; Thévenin, Frédéric (March 2019). "Stellar and substellar companions of nearby stars from Gaia DR2. Binarity from proper motion anomaly". Astronomy and Astrophysics. 623: A72. arXiv:1811.08902. Bibcode:2019A&A...623A..72K. doi:10.1051/0004-6361/201834371. ISSN 0004-6361. S2CID 119491061.
11. Kervella, Pierre; Arenou, Frédéric; Thévenin, Frédéric (2022). "Stellar and substellar companions from Gaia EDR3". Astronomy & Astrophysics. 657: A7. arXiv:2109.10912. Bibcode:2022A&A...657A...7K. doi:10.1051/0004-6361/202142146. eISSN 1432-0746. ISSN 0004-6361.
12. 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.
13. McDonald, I.; Zijlstra, A. A.; Watson, R. A. (15 June 2017). "Fundamental parameters and infrared excesses of Tycho–Gaia stars". Monthly Notices of the Royal Astronomical Society. 471 (1): 770–791. arXiv:1706.02208. Bibcode:2017MNRAS.471..770M. doi:10.1093/mnras/stx1433. eISSN 1365-2966. ISSN 0035-8711.
14. 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.
15. 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.
16. "AF Columbae". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved September 7, 2022.
17. 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.
18. Kazarovets, E. V.; Samus, N. N.; Durlevich, O. V.; Frolov, M. S.; Antipin, S. V.; Kireeva, N. N.; Pastukhova, E. N. (January 1999). "The 74th Special Name-list of Variable Stars" (PDF). Information Bulletin on Variable Stars. 4659: 1–27. Retrieved 26 January 2025.
19. Tabur, V.; Bedding, T. R.; Kiss, L. L.; Moon, T. T.; Szeidl, B.; Kjeldsen, H. (21 December 2009). "Long-term photometry and periods for 261 nearby pulsating M giants". Monthly Notices of the Royal Astronomical Society. 400 (4): 1945–1961. arXiv:0908.3228. Bibcode:2009MNRAS.400.1945T. doi:10.1111/j.1365-2966.2009.15588.x. eISSN 1365-2966. ISSN 0035-8711.
20. Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (October 12, 2010). "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun". Monthly Notices of the Royal Astronomical Society. 410 (1). Oxford University Press (OUP): 190–200. arXiv:1007.4883. Bibcode:2011MNRAS.410..190T. doi:10.1111/j.1365-2966.2010.17434.x. ISSN 0035-8711.