Wikipedia

Chi2 Fornacis

For other stars with a similar Bayer designation, see χ Fornacis.

Chi2 Fornacis, Latinized from χ2 Fornacis, is a solitary star[15] located in the southern constellation Fornax, the furnace. It is faintly visible to the naked eye as an orange-hued point of light with an apparent magnitude of 5.70. Gaia DR3 parallax measurements imply a distance of 476 light-years and it is currently receding with a heliocentric radial velocity of approximately 30 km/s.[6] At its current distance, Chi2 Fornacis' brightness is diminished by an interstellar extinction of 0.11 magnitudes[16] and it has an absolute magnitude of 0.00.[7]

χ2 Fornacis
Location of χ2 Fornacis (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Fornax
Right ascension 03h 27m 33.42119s[1]
Declination −35° 40′ 52.7728″[1]
Apparent magnitude (V) 5.70±0.01[2]
Characteristics
Spectral type K2 III[3]
B−V color index +1.29[4]
Variable type suspected[5]
Astrometry
Radial velocity (Rv)30.0±4.3[6] km/s
Proper motion (μ) RA: +77.064 mas/yr[1]
Dec.: +5.989 mas/yr[1]
Parallax (π)6.8558 ± 0.0446 mas[1]
Distance476 ± 3 ly
(145.9 ± 0.9 pc)
Absolute magnitude (MV)0.00[7]
Details
Mass1.18[8] M☉
Radius23.58±1.19[9] R☉
Luminosity194+4
−3[1] L☉
Surface gravity (log g)1.83[8] cgs
Temperature4,477±122[10] K
Metallicity [Fe/H]+0.02[11] dex
Rotational velocity (v sin i)<1.0[12] km/s
Other designations
χ2 For, 91 G. Fornacis[13], NSV 15697, CD−36°1306, CPD−36°355, FK5 2244, GC 4129, HD 21574, HIP 16112, HR 1054, SAO 194312, TIC 142889216[14]
Database references
SIMBADdata

Chi2 Fornacis is an old-disk star[11] and it has a stellar classification of K2 III.[3] The class indicates that it is an evolved K-type giant that has ceased hydrogen fusion at its core and left the main sequence. It has 118% the mass of the Sun[8] but it has expanded to 23.58 times the radius of the Sun.[9] It radiates 194 times the luminosity of the Sun[1] from its photosphere at an effective temperature of 4,477 K.[10] Chi2 Fornacis is slightly metal enriched with a near-solar iron abundance of [Fe/H] = +0.02.[11] It spins too slowly for its projected rotational velocity to be measured accurately, having a projected rotational velocity lower than 1.0 km/s.[12]

The star was observed to be variable in infrared light during a 1991 IRAS survey for galaxy clusters.[17] However, its variability in optical light is unknown. In addition, subsequent observations have not confirmed the variability in infrared and optical light.[18] The lenticular galaxy NGC 1380 lies 2 degrees north-northeast of Chi2 Fornacis.[19]

References

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  1. ^ a b c d e f 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. ^ a b Houk, N. (1982). Michigan Catalogue of Two-dimensional Spectral Types for the HD stars. Declinations −40° to −26°. Vol. 3. Bibcode:1982mcts.book.....H.
  4. ^ Johnson, H. L.; Mitchell, R. I.; Iriarte, B.; Wisniewski, W. Z. (1966). "UBVRIJKL Photometry of the Bright Stars". Communications of the Lunar and Planetary Laboratory. 4: 99–110. Bibcode:1966CoLPL...4...99J.
  5. ^ 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.
  6. ^ a b Gontcharov, G. A. (November 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. eISSN 1562-6873. ISSN 1063-7737. S2CID 119231169.
  7. ^ a b 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. ^ a b c 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.
  9. ^ a b Kervella, P.; Thévenin, F.; Di Folco, E.; Ségransan, D. (April 8, 2004). "The angular sizes of dwarf stars and subgiants: Surface brightness relations calibrated by interferometry". Astronomy & Astrophysics. 426 (1): 297–307. arXiv:astro-ph/0404180. Bibcode:2004A&A...426..297K. doi:10.1051/0004-6361:20035930. eISSN 1432-0746. ISSN 0004-6361. S2CID 6077801.
  10. ^ a b 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.
  11. ^ a b c Eggen, O. J. (July 1993). "Evolved GK stars near the sun. I - The old disk population". The Astronomical Journal. 106: 80. Bibcode:1993AJ....106...80E. doi:10.1086/116622.
  12. ^ a b De Medeiros, J. R.; Alves, S.; Udry, S.; Andersen, J.; Nordström, B.; Mayor, M. (January 2014). "A catalog of rotational and radial velocities for evolved stars V: Southern stars *". Astronomy & Astrophysics. 561: A126. arXiv:1312.3474. Bibcode:2014A&A...561A.126D. doi:10.1051/0004-6361/201220762. eISSN 1432-0746. ISSN 0004-6361. S2CID 54046583.
  13. ^ 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.
  14. ^ "Chi02 For". simbad.cds.unistra.fr. Retrieved 2024-01-18.
  15. ^ 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.
  16. ^ 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.
  17. ^ Wang, G.; Clowes, R. G.; Leggett, S. K.; MacGillivray, H. T.; Savage, A. (1991). "Optical identifications of IRAS point sources: the Fornax, Hydra I and Coma clusters". Monthly Notices of the Royal Astronomical Society. 248 (1): 112–127. Bibcode:1991MNRAS.248..112W. doi:10.1093/mnras/248.1.112. ISSN 0035-8711. S2CID 120387905.
  18. ^ 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.
  19. ^ O'Meara, Stephen James (2013). Deep-Sky Companions: Southern Gems. Cambridge University Press. pp. 78–80. Bibcode:2013dcsg.book.....O. ISBN 9781107015012.
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