HD 165259

HD 165259
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Apus
A
Right ascension 18h 12m 34.08358s[1]
Declination −73° 40′ 20.7691″[1]
Apparent magnitude (V) 5.91[2]
B
Right ascension 18h 12m 33.47381s[3]
Declination −73° 40′ 20.9419″[3]
Apparent magnitude (V) 9.03[2]
Characteristics
A
Spectral type F5V[4]
U−B color index +0.05[5]
B−V color index +0.46[5]
B
Spectral type G1 V[6]
U−B color index +0.74[6]
B−V color index +1.06[6]
Astrometry
Radial velocity (Rv)13.1±1[7] km/s
Absolute magnitude (MV)+2.74[8]
A
Proper motion (μ) RA: −91.400[1] mas/yr
Dec.: −254.341[1] mas/yr
Parallax (π)23.6778±0.0399 mas[1]
Distance137.7 ± 0.2 ly
(42.23 ± 0.07 pc)
B
Proper motion (μ) RA: −62.130[3] mas/yr
Dec.: −241.999[3] mas/yr
Parallax (π)23.7101 ± 0.0338 mas[3]
Distance137.6 ± 0.2 ly
(42.18 ± 0.06 pc)
Orbit[9]
PrimaryA
CompanionB
Period (P)450 yr
Semi-major axis (a)2.014″
Eccentricity (e)0.3
Inclination (i)46.7°
Longitude of the node (Ω)65.3°
Periastron epoch (T)2147.2
Argument of periastron (ω)
(primary)		348.8°
Orbit[9]
PrimaryAa
CompanionAb
Period (P)44.2 yr
Semi-major axis (a)0.373″
Eccentricity (e)0
Inclination (i)83.5°
Longitude of the node (Ω)105.2°
Periastron epoch (T)2027.22
Argument of periastron (ω)
(primary)		0°
Details
Aa
Mass1.46[9] M☉
Radius2.04[1] R☉
Luminosity6.2[1] L☉
Surface gravity (log g)3.92[10] cgs
Temperature6,411±218[10] K
Metallicity [Fe/H]+0.26[11] dex
Rotational velocity (v sin i)<5[12] km/s
Age1.8+0.1
−0.2[12] Gyr
Ab
Mass0.73[9] M☉
B
Mass0.82[9] M☉
Surface gravity (log g)4.3[13] cgs
Temperature5,328[13] K
Metallicity [Fe/H]−0.22[13] dex
Other designations
67 G. Apodis[14], CD−73°1348, CPD−73°1888, GC 24731, HD 165259, HIP 89234, HR 6751, SAO 257571, WDS J18126-7340AB[15]
Database references
SIMBADdata

HD 165259, also known as HR 6751 is a triple star system located in the southern circumpolar constellation of Apus. It has an apparent magnitude of 5.86,[8] making it faintly visible to the naked eye. Parallax measurements place the system at a distance of 138 light years,[1][3] and it is currently receding with a heliocentric radial velocity of 13.1 km/s.[7]

HD 165259 consists of two main sequence stars, with stellar classifications of F5 V[4] and G1 V,[6] separated by two arc-seconds as of 2020.[16] Speckle interferometry in 2008 revealed the primary to be a close binary itself, with the two components separated by 0.3″.[17] By 2020, the separation had decreased to 0.2″.[16] The outer pair take 542 years to complete a revolution while the inner pair complete their orbit within 32 years.[18]

At present the primary is somewhat more massive than the Sun and a slightly enlarged radius of 2.0 R☉ as it is nearing the end of its main sequence life.[1] It radiates at 6.2 times the luminosity of the Sun[1] from its photosphere at an effective temperature of 6,411 K,[10] giving a yellow-white hue. HD 165259A has an iron abundance 82% above solar levels,[11] making it metal enriched. It is estimated to be nearly 2 billion years old and has a projected rotational velocity of less than 5 km/s.[12] HD 165259B has 82% the mass of the Sun[9] and an effective temperature of 5,328 K,[13] giving an orange glow. The faint star orbiting the primary has a mass 73% that of the Sun.[9]

References

  1. 1 2 3 4 5 6 7 8 9 10 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 Fabricius, C.; Høg, E.; Makarov, V. V.; Mason, B. D.; Wycoff, G. L.; Urban, S. E. (March 2002). "The Tycho double star catalogue". Astronomy & Astrophysics. 384 (1): 180–189. Bibcode:2002A&A...384..180F. doi:10.1051/0004-6361:20011822. ISSN 0004-6361.
  3. 1 2 3 4 5 6 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.
  4. 1 2 Houk, N.; Cowley, A. P. (1975). University of Michigan Catalogue of two-dimensional spectral types for the HD stars. Volume I. Declinations −90° to −53°. Bibcode:1975mcts.book.....H.
  5. 1 2 Nicolet, B. (1978). "Photoelectric photometric Catalogue of homogeneous measurements in the UBV System". Astronomy and Astrophysics Supplement Series. 34: 1–49. Bibcode:1978A&AS...34....1N.
  6. 1 2 3 4 Corbally, C. J. (August 1984). "Close visual binaries. I - MK classifications". The Astrophysical Journal Supplement Series. 55: 657. Bibcode:1984ApJS...55..657C. doi:10.1086/190973. eISSN 1538-4365. ISSN 0067-0049.
  7. 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.
  8. 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.
  9. 1 2 3 4 5 6 7 Tokovinin, Andrei (2025). "Orbits of Six Triple Systems". The Astronomical Journal. 169 (3): 124. arXiv:2501.04807. Bibcode:2025AJ....169..124T. doi:10.3847/1538-3881/ada3c6.
  10. 1 2 3 David, Trevor J.; Hillenbrand, Lynne A. (12 May 2015). "The Ages of Early-type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets". The Astrophysical Journal. 804 (2): 146. arXiv:1501.03154. Bibcode:2015ApJ...804..146D. doi:10.1088/0004-637X/804/2/146. eISSN 1538-4357.
  11. 1 2 Casagrande, L.; Schönrich, R.; Asplund, M.; Cassisi, S.; Ramírez, I.; Meléndez, J.; Bensby, T.; Feltzing, S. (26 May 2011). "New constraints on the chemical evolution of the solar neighbourhood and Galactic disc(s): Improved astrophysical parameters for the Geneva-Copenhagen Survey⋆". Astronomy & Astrophysics. 530: A138. arXiv:1103.4651. Bibcode:2011A&A...530A.138C. doi:10.1051/0004-6361/201016276. eISSN 1432-0746. ISSN 0004-6361.
  12. 1 2 3 Nordström, B.; Mayor, M.; Andersen, J.; Holmberg, J.; Pont, F.; Jørgensen, B. R.; Olsen, E. H.; Udry, S.; Mowlavi, N. (16 April 2004). "The Geneva-Copenhagen survey of the Solar neighbourhood". Astronomy & Astrophysics. 418 (3): 989–1019. arXiv:astro-ph/0405198. Bibcode:2004A&A...418..989N. doi:10.1051/0004-6361:20035959. eISSN 1432-0746. ISSN 0004-6361.
  13. 1 2 3 4 Anders, F.; et al. (February 2022). "Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia EDR3 stars brighter than G = 18.5". Astronomy & Astrophysics. 658: A91. arXiv:2111.01860. Bibcode:2022A&A...658A..91A. doi:10.1051/0004-6361/202142369. eISSN 1432-0746. ISSN 0004-6361.
  14. ↑ 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.
  15. ↑ "HR 6635". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved August 15, 2022.
  16. 1 2 Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I.; Douglass, Geoffrey G.; Worley, Charles E. (December 2001). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog". The Astronomical Journal. 122 (6): 3466–3471. Bibcode:2001AJ....122.3466M. doi:10.1086/323920. ISSN 0004-6256.
  17. ↑ Tokovinin, Andrei; Mason, Brian D.; Hartkopf, William I. (2010). "Speckle Interferometry at the Blanco and SOAR Telescopes in 2008 and 2009". The Astronomical Journal. 139 (2): 743–756. arXiv:0911.5718. Bibcode:2010AJ....139..743T. doi:10.1088/0004-6256/139/2/743. S2CID 26379213.
  18. ↑ Tokovinin, Andrei (14 March 2014). "From Binaries to Multiples. II. Hierarchical Multiplicity of F and G Dwarfs". The Astronomical Journal. 147 (4): 87. arXiv:1401.6827. Bibcode:2014AJ....147...87T. doi:10.1088/0004-6256/147/4/87. eISSN 1538-3881. ISSN 0004-6256.
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