18 Sextantis

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18 Sextantis
Sextans constellation map.svg
Red circle.svg
Location of 18 Sex on the map (circled)
Observation data
Epoch J2000.0        Equinox J2000.0 (ICRS)
Constellation Sextans
Right ascension 10h 10m 55.86074s [1]
Declination −08° 25′ 06.4527″ [1]
Apparent magnitude  (V)5.62±0.01 [2]
Characteristics
Spectral type K2/3 III [3]
U−B color index +1.42 [4]
B−V color index +1.30 [4]
Astrometry
Radial velocity (Rv)0.2±2.9 [5] km/s
Proper motion (μ)RA: −0.115 mas/yr [1]
Dec.: −43.987 mas/yr [1]
Parallax (π)5.8416±0.0881  mas [1]
Distance 558 ± 8  ly
(171 ± 3  pc)
Absolute magnitude  (MV)−0.16 [6]
Details
Radius 27.3±1.4 [7]   R☉
Luminosity 222±12 [8]   L☉
Surface gravity (log g)1.72 [9]   cgs
Temperature 4,410±122 [10]   K
Metallicity [Fe/H]−0.31+0.01
−0.00 [11]   dex
Rotational velocity (v sin i)<1.0 [12]  km/s
Other designations
18 Sex, 32 G. Sextantis [13] , BD−07°2977, GC 13990, HD 88333, HIP 49865, HR 3996, SAO 137395, TIC 26206896 [14]
Database references
SIMBAD data

18 Sextantis (HD 88333; HR 3996; 32 G. Sextantis), or simply 18 Sex, is a solitary star [15] located in the southern constellation Sextans. It is faintly visible to the naked eye as an orange-hued point of light with an apparent magnitude of 5.62. [2] Gaia DR3 parallax measurements imply a distance of 558 light-years [1] and it is slowly receding with a poorly constrained heliocentric radial velocity of approximately 0.2  km/s . [5] At its current distance, 18 Sex's brightness is diminished with an interstellar extinction of two-tenths of a magnitude [16] and it has an absolute magnitude of −0.16. [6]

18 Sex has a stellar classification of K2/3 III, [3] indicating that it is an evolved star with the characteristics of a K2 and K3 giant star. At present, it has exhausted hydrogen at its core and it has expanded to 27.3 times the radius of the Sun. [7] It radiates 222 times the luminosity of the Sun [8] from its enlarged photosphere at an effective temperature of 4,410  K . [10] Gaia DR3 models it to be a larger and brighter red giant branch star with a radius of 35.27  R☉ and a luminosity of 384  L☉. [1] 18 Sex is metal deficient with an iron abundance of [Fe/H] = −0.31 or 49% of the Sun's [11] and it spins too slowly for its projected rotational velocity to be measured accurately, having a velocity lower than 1.0  km/s . [12]

See also

References

  1. 1 2 3 4 5 6 7 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. 1 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. 1 2 Houk, Nancy; Swift, Carrie (1999). Michigan catalogue of two-dimensional spectral types for the HD Stars; vol. 5. Bibcode:1999mctd.book.....H.
  4. 1 2 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. 1 2 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.
  6. 1 2 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.
  7. 1 2 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.
  8. 1 2 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.
  9. ↑ 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. S2CID   73594365.
  10. 1 2 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. 1 2 Poggio, E.; Recio-Blanco, A.; Palicio, P. A.; Re Fiorentin, P.; de Laverny, P.; Drimmel, R.; Kordopatis, G.; Lattanzi, M. G.; Schultheis, M.; Spagna, A.; Spitoni, E. (30 September 2022). "The chemical signature of the Galactic spiral arms revealed by Gaia DR3". Astronomy & Astrophysics. 666: L4. arXiv: 2206.14849 . Bibcode:2022A&A...666L...4P. doi: 10.1051/0004-6361/202244361 . eISSN   1432-0746. ISSN   0004-6361.
  12. 1 2 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. ↑ "* 18 Sex". SIMBAD . Centre de données astronomiques de Strasbourg.
  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.
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