Wikipedia

19 Sextantis

19 Sextantis (HD 88547; HR 4004; 34 G. Sextantis), or simply 19 Sex, is a solitary star[13] located in the equatorial constellation Sextans. It is faintly visible to the naked eye as an orange-hued point of light with an apparent magnitude of 5.78.[2] Gaia DR3 parallax measurements imply a distance of 516 light-years[1] and it is currently receding with a heliocentric radial velocity of 31.8 km/s.[7] At its current distance, 19 Sex's brightness is diminished by an interstellar extinction of 0.17 magnitudes.[14]

19 Sextantis
Location of 19 Sex on the map (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Sextans
Right ascension 10h 12m 48.36462s[1]
Declination +04° 36′ 52.8378″[1]
Apparent magnitude (V) 5.78±0.01[2]
Characteristics
Evolutionary stage red giant branch[3]
Spectral type K1 III[4] or K0 III[5]
U−B color index +1.11[6]
B−V color index +1.18[6]
Astrometry
Radial velocity (Rv)31.80±0.21[7] km/s
Proper motion (μ) RA: −50.538 mas/yr[1]
Dec.: −6.118 mas/yr[1]
Parallax (π)6.3184 ± 0.0625 mas[1]
Distance516 ± 5 ly
(158 ± 2 pc)
Details
Mass0.88+0.08
−0.03[3] M☉
Radius23.13±1.17[8] R☉
Luminosity241+4
−5[1] L☉
Temperature4,576±123[9] K
Metallicity [Fe/H]−0.53[10] dex
Rotational velocity (v sin i)2.5±0.8[4] km/s
Age7.94+1.83
−0.70[3] Gyr
Other designations
19 Sex, 34 G. Sextantis[11], AG+04°1386, BD+05°2301, GC 14022, HD 88547, HIP 50027, HR 4004, SAO 118164, TIC 277696329[12]
Database references
SIMBADdata

19 Sex has a stellar classification of K1 III,[4] indicating that it is an evolved K-type giant star that has ceased hydrogen fusion at it core and it has left the main sequence. It has also been given a slightly hotter class of K0 III.[5] Stellar evolution models from Stock et al. (2018) model it to be a red giant branch star (100% chance)[3] that is currently fusing a hydrogen shell around an inert helium core. It has 88% the mass of the Sun but at the age of 7.94 billion years,[3] it has expanded to 23.13 times the radius of the Sun.[8] It radiates 241 times the luminosity of the Sun[1] from its photosphere at an effective temperature of 4,576 K.[9] 19 Sex is metal deficient with an iron abundance of [Fe/H] = −0.53 or 29.5% of the Sun's[10] and it spins modestly with a projected rotational velocity of 2.5 km/s.[4]

References

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  1. ^ a b c d e f g 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. ^ a b 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 c d e Stock, Stephan; Reffert, Sabine; Quirrenbach, Andreas (August 2018). "Precise radial velocities of giant stars: X. Bayesian stellar parameters and evolutionary stages for 372 giant stars from the Lick planet search". Astronomy & Astrophysics. 616: A33. arXiv:1805.04094. Bibcode:2018A&A...616A..33S. doi:10.1051/0004-6361/201833111. ISSN 0004-6361. S2CID 247657118.
  4. ^ a b c d Henry, Gregory W.; Fekel, Francis C.; Henry, Stephen M.; Hall, Douglas S. (September 2000). "Photometric Variability in a Sample of 187 G and K Giants". The Astrophysical Journal Supplement Series. 130 (1): 201–225. Bibcode:2000ApJS..130..201H. doi:10.1086/317346. ISSN 0067-0049.
  5. ^ a b Adams, Walter S.; Joy, Alfred H.; Humason, Milton L.; Brayton, Ada Margaret (April 1935). "The Spectroscopic Absolute Magnitudes and Parallaxes of 4179 Stars". The Astrophysical Journal. 81: 187. Bibcode:1935ApJ....81..187A. doi:10.1086/143628. eISSN 1538-4357. ISSN 0004-637X. S2CID 121056016.
  6. ^ a b 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.
  7. ^ a b Famaey, B.; Jorissen, A.; Luri, X.; Mayor, M.; Udry, S.; Dejonghe, H.; Turon, C. (January 2005). "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters". Astronomy and Astrophysics. 430: 165. arXiv:astro-ph/0409579. Bibcode:2005A&A...430..165F. doi:10.1051/0004-6361:20041272. S2CID 17804304.
  8. ^ 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.
  9. ^ 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.
  10. ^ a b Hekker, S.; Meléndez, J. (December 2007). "Precise radial velocities of giant stars: III. Spectroscopic stellar parameters". Astronomy & Astrophysics. 475 (3): 1003–1009. arXiv:0709.1145. Bibcode:2007A&A...475.1003H. doi:10.1051/0004-6361:20078233. ISSN 0004-6361. S2CID 10436552.
  11. ^ 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.
  12. ^ "*19 Sex". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved January 13, 2024.
  13. ^ 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.
  14. ^ 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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