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 346 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
[edit]- ^ a b c 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.
- ^ 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.
- ^ 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.
- ^ a b c d 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.
- ^ a b 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.
- ^ a b 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.
- ^ a b 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.
- ^ a b c d 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.
- ^ a b c d 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.
- ^ 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.
- ^ a b c 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.
- ^ a b 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.
- ^ a b 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.
- ^ 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.
- ^ "HD 86320". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved November 18, 2025.
