19 Sextantis

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

19 Sextantis (HD 88547; HR 4004; 34 G. Sextantis), or simply 19 Sex, is a solitary star 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. Gaia DR3 parallax measurements imply a distance of 516 light-years and it is currently receding with a heliocentric radial velocity of 31.8 km/s. At its current distance, 19 Sex's brightness is diminished by an interstellar extinction of 0.17 magnitudes.

19 Sex has a stellar classification of K1 III, 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. Stellar evolution models from Stock et al. (2018) model it to be a red giant branch star (100% chance) 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, it has expanded to 23.13 times the radius of the Sun. It radiates 241 times the luminosity of the Sun from its photosphere at an effective temperature of 4,576 K. 19 Sex is metal deficient with an iron abundance of [Fe/H] = −0.53 or 29.5% of the Sun's and it spins modestly with a projected rotational velocity of 2.5 km/s.

References

  1. 1 2 3 4 5 6 7 8 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 3 4 5 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. 1 2 3 4 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. 1 2 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. 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.
  7. 1 2 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. 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.
  9. 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.
  10. 1 2 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.