HD 86320

Last updated
HD 86320
Observation data
Epoch J2000.0        Equinox J2000.0 (ICRS)
Constellation Chamaeleon [1]
Right ascension 09h 51m 00.81459s [2]
Declination −80° 03′ 39.7714″ [2]
Apparent magnitude  (V)6.49 [3] (6.69 + 8.62) [4]
Characteristics
Spectral type B8 IV [5]
U−B color index −0.23 [6]
B−V color index +0.06 [6]
Astrometry
Radial velocity (Rv)12.1±2.1 [7] km/s
Proper motion (μ)RA: −7.109 mas/yr [2]
Dec.: +8.963 mas/yr [2]
Parallax (π)3.9544±0.1015  mas [2]
Distance 820 ± 20  ly
(253 ± 6  pc)
Absolute magnitude  (MV)−0.54 [1]
Orbit [8]
Period (P)63.52±5.680  yr
Semi-major axis (a)0.1583±0.0057″
Eccentricity (e)0.50 (fixed)
Inclination (i)34.5±7.0°
Longitude of the node (Ω)142.3±15.8°
Periastron epoch (T)2,457,108.1±451.1  JD
Argument of periastron (ω)
(secondary)		135.2±20.9°
Details
A
Mass 3.069+1.059
−1.104 [9]   M☉
Radius 4.95±0.25 [10]   R☉
Luminosity 332.2+16.8
−15.5 [2]   L☉
Surface gravity (log g)3.49 [11]   cgs
Temperature 10,257±1 [9]   K
Metallicity [Fe/H]0.00 [11]   dex
Rotational velocity (v sin i)>250 [12]  km/s
Age 360 [13] [ failed verification ]  Myr
B
Mass 1.6 [8]   M☉
Other designations
18 G. Chamaeleontis [14] , CPD−79°457, FK5 2791, GC 13624, HD 86320, HIP 48320, SAO 256666, WDS J09510-8004AB [15]
Database references
SIMBAD data

HD 86320 (HIP 48320; 18 G. Chamaeleontis) is a binary star located in the southern circumpolar constellation Chamaeleon. With a combined apparent magnitude of 6.49, [3] the system is a challenge to view with the naked eye, even under ideal conditions. When resolved, the apparent magnitudes of the components are 6.69 and 8.62 respectively. [4] The system is located relatively far at a distance of 820 light years based on Gaia DR3 parallax measurements, [2] and it is drifting away from the Solar System with a heliocentric radial velocity of roughly 12.1  km/s . [7] It has an absolute magnitude of −0.54. [1]

The binary natue of this system was first observed in a 1991 Hipparcos multiple star survey. [4] A preliminary orbit was calculated for the system in 2016. In this solution, the stars take 63.52 years to circle each other in an eccentric orbit at a separation of 0.1583". [8] As of 2021, the 8th magnitude companion is located roughly 0.1" away at a position angle of 344°. [4]

The system has a combined spectral classification of B8 IV, [5] indicating that it is a slightly evolved B-type subgiant that is beginning to cease hydrogen fusion at its core. The primary has 3.07 times the mass of the Sun [9] and 4.95 times the radius of the Sun. [10] It radiates 332.2 times the luminosity of the Sun [2] from its photosphere at an effective temperature of 10,257  K , [9] giving it a bluish-white hue when viewed in the night sky. HD 86320 A has a solar metallicity, [11] and it is estimated to be 360 million years old. [13] It spins rapidly with a projected rotational velocity that is greater than 250  km/s . [12] The companion has 1.6 times the mass of the Sun based on the orbital solution. [8]

References

  1. 1 2 3 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters . 38 (5): 331. arXiv: 1108.4971 . Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. XHIP record for this object at VizieR.
  2. 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.
  3. 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.
  4. 1 2 3 4 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. S2CID   119533755.
  5. 1 2 Houk, N.; Cowley, A. P. (1975). University of Michigan Catalogue of two-dimensional spectral types for the HD stars: Declinations −90° to −53°. Vol. 1. Bibcode:1975mcts.book.....H.
  6. 1 2 Moreno, H.; Carrasco, G. (July 1986). "UBVRI photometry of FK4 and FK4 supplement stars". Astronomy and Astrophysics Supplement Series. 65: 33–39. Bibcode:1986A&AS...65...33M. ISSN   0365-0138.
  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 3 4 Tokovinin, Andrei (2016). "New Orbits Based on Speckle Interferometry at SOAR". The Astronomical Journal. 152 (5): 138. arXiv: 1608.01242 . Bibcode:2016AJ....152..138T. doi: 10.3847/0004-6256/152/5/138 .
  9. 1 2 3 4 Quintana, Alexis L; Wright, Nicholas J; García, Juan Martínez (March 17, 2025). "A census of OB stars within 1 kpc and the star formation and core collapse supernova rates of the Milky Way". Monthly Notices of the Royal Astronomical Society. 538 (3): 1367–1383. arXiv: 2503.08286 . Bibcode:2025MNRAS.538.1367Q. doi: 10.1093/mnras/staf083 . ISSN   0035-8711. S2CID   276890814.
  10. 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.
  11. 1 2 3 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.
  12. 1 2 Andersen, J.; Nordstrom, B. (1983). "Radial velocities of bright southern stars. I - 139 B-type HR and FK stars". Astronomy and Astrophysics Supplement Series. 52: 471–482. Bibcode:1983A&AS...52..471A.
  13. 1 2 Gontcharov, G. A. (November 2012). "Spatial distribution and kinematics of OB stars". Astronomy Letters. 38 (11): 694–706. arXiv: 1606.09028 . Bibcode:2012AstL...38..694G. doi:10.1134/S1063773712110035. eISSN   1562-6873. ISSN   1063-7737. S2CID   255202762.
  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. ↑ "HD 86320". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved November 18, 2025.
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