HD 86320

HD 86320
Observation data
Epoch J2000.0      Equinox ICRS
Constellation Chamaeleon
Right ascension 09h 51m 00.81459s
Declination −80° 03′ 39.7714″
Apparent magnitude (V) 6.49 (6.69 + 8.62)
Characteristics
Spectral type B8 IV
U−B color index −0.23
B−V color index +0.06
Astrometry
Radial velocity (Rv)12.1±2.1 km/s
Proper motion (μ) RA: −7.109 mas/yr
Dec.: +8.963 mas/yr
Parallax (π)3.9544±0.1015 mas
Distance820 ± 20 ly
(253 ± 6 pc)
Absolute magnitude (MV)−0.54
Orbit
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
Mass3.069+1.059
−1.104 M☉
Radius4.95±0.25 R☉
Luminosity332.2+16.8
−15.5 L☉
Surface gravity (log g)3.49 cgs
Temperature10,257±1 K
Metallicity [Fe/H]0.00 dex
Rotational velocity (v sin i)>250 km/s
Age346 Myr
B
Mass1.6 M☉
Other designations
18 G. Chamaeleontis, CPD−79°457, FK5 2791, GC 13624, HD 86320, HIP 48320, SAO 256666, WDS J09510-8004AB
Database references
SIMBADdata

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, 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. The system is located relatively far at a distance of 820 light years based on Gaia DR3 parallax measurements, and it is drifting away from the Solar System with a heliocentric radial velocity of roughly 12.1 km/s. It has an absolute magnitude of −0.54.

The binary natue of this system was first observed in a 1991 Hipparcos multiple star survey. 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". As of 2021, the 8th magnitude companion is located roughly 0.1" away at a position angle of 344°.

The system has a combined spectral classification of B8 IV, 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 and 4.95 times the radius of the Sun. It radiates 332.2 times the luminosity of the Sun from its photosphere at an effective temperature of 10,257 K, giving it a bluish-white hue when viewed in the night sky. HD 86320 A has a solar metallicity, and it is estimated to be 346 million years old. It spins rapidly with a projected rotational velocity that is greater than 250 km/s. The companion has 1.6 times the mass of the Sun based on the orbital solution.

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. (2012). "Dependence of kinematics on the age of stars in the solar neighborhood". Astronomy Letters. 38 (12): 771. arXiv:1606.08814. Bibcode:2012AstL...38..771G. doi:10.1134/S1063773712120031.
  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.