HD 178322

HD 178322
Location of HD 178322 (circled)
Observation data
Epoch J2000.0      Equinox ICRS
Constellation Corona Australis
Right ascension 19h 09m 57.65200s
Declination −41° 53′ 32.0836″
Apparent magnitude (V) 5.86±0.01
Characteristics
Spectral type B5 V + B6 V
U−B color index −0.49
B−V color index −0.08
Variable type suspected
Astrometry
Radial velocity (Rv)13.3±2 km/s
Proper motion (μ) RA: −0.360 mas/yr
Dec.: −10.096 mas/yr
Parallax (π)2.104±0.1145 mas
Distance1,550 ± 80 ly
(480 ± 30 pc)
Absolute magnitude (MV)−2.31 (combined)
Orbit
PrimaryA
SecondaryB
Period (P)12.4700 d
Semi-major axis (a)0.235 AU
Eccentricity (e)0.05
Inclination (i)71.19°
Periastron epoch (T)2,438,237.4500 JD
Argument of periastron (ω)
(secondary)		199.1°
Argument of periastron (ω)
(primary)		19.10°
Semi-amplitude (K1)
(primary)		79.70 km/s
Semi-amplitude (K2)
(secondary)		78.90 km/s
Details
Age50.1±8.4 Myr
A
Mass4.39 M☉
Radius3.26 R☉
Luminosity11,749 L☉
Temperature15,488 K
Rotational velocity (v sin i)45 km/s
B
Mass4.35 M☉
Radius3.07 R☉
Luminosity513 L☉
Temperature14,454 K
Rotational velocity (v sin i)45±7 km/s
Other designations
45 G. Coronae Australis, CD−42°13933, CPD−42°8616, GC 26375, HD 178322, HIP 94157, HR 7257, SAO 229531
Database references
SIMBADdata

HD 178322, also known as HR 7257 or rarely 45 G. Coronae Australis, is a double-lined spectroscopic binary located in the southern constellation Corona Australis. It has a combined apparent magnitude of 5.86, making it faintly visible to the naked eye under ideal conditions. The system is located relatively far at a distance of roughly 1,550 light-years based on Gaia DR3 parallax measurements, and it is currently receding with a heliocentric radial velocity of 13.3 km/s. At its current distance, HD 178322's brightness is diminished by an extinction of 0.28 magnitudes and it has an absolute magnitude of −2.31. The system has a high peculiar velocity of 28.9+4.1
−7.9 km/s, indicating that it may be a runaway star system; it is said to be part of the Scorpius-Centaurus Association.

The components of HD 178322 are both B-type main-sequence stars with stellar classifications of B5 V and B6 V respectively. Both stars have roughly 4.4 times the mass of the Sun and they spin moderately with projected rotational velocities of 45 km/s. The primary has 3.26 times the radius of the Sun and it radiates 11,749 times the luminosity of the Sun from its photosphere at an effective temperature of 15,488 K. The companion has 3.07 times the Sun's girth and it radiates 513 times the luminosity of the Sun from its photosphere at an effective temperature of 14,454 K. Both stars take roughly 12 days to complete a relatively circular orbit at a separation of 0.235 AU. The system is estimated to be 50 million years old.

References

  1. 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.
  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 Levato, H. (January 1975). "Rotational velocities and spectral types for a sample of binary systems". Astronomy and Astrophysics Supplement Series. 19: 91–99. Bibcode:1975A&AS...19...91L. ISSN 0365-0138. S2CID 118523421.
  4. 1 2 Gutierrez-Moreno, Adelina; Moreno, Hugo (June 1968). "A Photometric Investigation of the SCORPlO-CENTAURUS Association". The Astrophysical Journal Supplement Series. 15: 459. Bibcode:1968ApJS...15..459G. doi:10.1086/190168. eISSN 1538-4365. ISSN 0067-0049. S2CID 123957668.
  5. ↑ Samus’, N. N.; Kazarovets, E. V.; Durlevich, O. V.; Kireeva, N. N.; Pastukhova, E. N. (January 2017). "General catalogue of variable stars: Version GCVS 5.1". Astronomy Reports. 61 (1): 80–88. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085. eISSN 1562-6881. ISSN 1063-7729. S2CID 125853869.
  6. 1 2 Evans, David S. (June 20–24, 1966), "The Revision of the General Catalogue of Radial Velocities", in Batten, Alan Henry; Heard, John Frederick (eds.), Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30, vol. 30, University of Toronto: International Astronomical Union, p. 57, Bibcode:1967IAUS...30...57E, doi:10.1017/S007418090010662X (inactive 1 July 2025), S2CID 122899856{{citation}}: CS1 maint: DOI inactive as of July 2025 (link)
  7. 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.
  8. 1 2 Thackeray, A. D.; Hutchings, J. B. (1 February 1965). "Orbits of Two Double-lined Binaries HD 140008 and 178322". Monthly Notices of the Royal Astronomical Society. 129 (2): 191–197. Bibcode:1965MNRAS.129..191T. doi:10.1093/mnras/129.2.191. eISSN 1365-2966. ISSN 0035-8711. S2CID 125267464.
  9. 1 2 3 4 5 6 7 8 9 Howe, K. S.; Clarke, C. J. (1 January 2009). "An analysis of v sin (i) correlations in early-type binaries". Monthly Notices of the Royal Astronomical Society. 392 (1): 448–454. Bibcode:2009MNRAS.392..448H. doi:10.1111/j.1365-2966.2008.14073.x. eISSN 1365-2966. ISSN 0035-8711. S2CID 120183969.
  10. 1 2 3 4 5 Kraicheva, Z.; Popova, E.; Tutukov, A.; Yungelson, L. (July 1980). "Catalogue of physical parameters of spectroscopic binary stars". Bull. Inf. Centre Données Stellaires. 19: 71. Bibcode:1980BICDS..19...71K. S2CID 118298938.
  11. 1 2 3 Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (October 12, 2010). "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun". Monthly Notices of the Royal Astronomical Society. 410 (1). Oxford University Press (OUP): 190–200. arXiv:1007.4883. Bibcode:2011MNRAS.410..190T. doi:10.1111/j.1365-2966.2010.17434.x. ISSN 0035-8711. S2CID 118629873.
  12. 1 2 3 4 5 6 7 Vansina, F.; De Grève, J. P. (October 1982). "Close binary systems before and after mass transfer". Astrophysics and Space Science. 87 (1–2): 377–401. Bibcode:1982Ap&SS..87..377V. doi:10.1007/BF00648931. eISSN 1572-946X. ISSN 0004-640X. S2CID 123986012.
  13. ↑ 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.
  14. ↑ "HD 178322". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved May 30, 2023.
  15. ↑ Schmidt-Kaler, Th. (October 1982). "Automated spectral classification. A survey". Bulletin d'Information du Centre de Donnees Stellaires. 23: 2. Bibcode:1982BICDS..23....2S. ISSN 1169-8837. S2CID 230958433.
  16. ↑ Buscombe, W.; Morris, P. M. (1 September 1960). "The Scorpio-Centaurus Association: I. Radial Velocities of 120 Bright Stars". Monthly Notices of the Royal Astronomical Society. 121 (3): 263–278. Bibcode:1960MNRAS.121..263B. doi:10.1093/mnras/121.3.263. eISSN 1365-2966. ISSN 0035-8711. S2CID 121858509.