HD 178322

HD 178322
Location of HD 178322 (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Corona Australis
Right ascension 19h 09m 57.65200s[1]
Declination −41° 53′ 32.0836″[1]
Apparent magnitude (V) 5.86±0.01[2]
Characteristics
Spectral type B5 V + B6 V[3]
U−B color index −0.49[4]
B−V color index −0.08[4]
Variable type suspected[5]
Astrometry
Radial velocity (Rv)13.3±2[6] km/s
Proper motion (μ) RA: −0.360 mas/yr[1]
Dec.: −10.096 mas/yr[1]
Parallax (π)2.104 ± 0.1145 mas[1]
Distance1,550 ± 80 ly
(480 ± 30 pc)
Absolute magnitude (MV)−2.31[7] (combined)
Orbit[8]
PrimaryA
CompanionB
Period (P)12.4700 d
Semi-major axis (a)0.235 AU[9]
Eccentricity (e)0.05
Inclination (i)71.19°
Periastron epoch (T)2,438,237.4500 JD
Argument of periastron (ω)
(secondary)		199.1[10]°
Argument of periastron (ω)
(primary)		19.10[10]°
Semi-amplitude (K1)
(primary)		79.70 km/s
Semi-amplitude (K2)
(secondary)		78.90 km/s
Details
Age50.1±8.4[11] Myr
A
Mass4.39[10] M☉
Radius3.26[9] R☉
Luminosity11,749[12] L☉
Temperature15,488[12] K
Rotational velocity (v sin i)45[9] km/s
B
Mass4.35[10] M☉
Radius3.07[9] R☉
Luminosity513[12] L☉
Temperature14,454[12] K
Rotational velocity (v sin i)45±7[9] km/s
Other designations
45 G. Coronae Australis[13], CD−42°13933, CPD−42°8616, GC 26375, HD 178322, HIP 94157, HR 7257, SAO 229531[14]
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,[2] 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,[1] and it is currently receding with a heliocentric radial velocity of 13.3 km/s.[6] At its current distance, HD 178322's brightness is diminished by an extinction of 0.28 magnitudes[15] and it has an absolute magnitude of −2.31.[7] The system has a high peculiar velocity of 28.9+4.1
−7.9 km/s,[11] indicating that it may be a runaway star system; it is said to be part of the Scorpius-Centaurus Association.[16]

The components of HD 178322 are both B-type main-sequence stars with stellar classifications of B5 V and B6 V respectively.[3] Both stars have roughly 4.4 times the mass of the Sun[10] and they spin moderately with projected rotational velocities of 45 km/s.[9] The primary has 3.26 times the radius of the Sun[9] and it radiates 11,749 times the luminosity of the Sun[12] from its photosphere at an effective temperature of 15,488 K. The companion has 3.07 times the Sun's girth[9] and it radiates 513 times the luminosity of the Sun[12] from its photosphere at an effective temperature of 14,454 K.[12] Both stars take roughly 12 days to complete a relatively circular orbit[8] at a separation of 0.235 AU.[9] The system is estimated to be 50 million years old.[11]

  1. ^ a b c d e Cite error: The named reference GaiaDR3 was invoked but never defined (see the help page).
  2. ^ a b Cite error: The named reference Tycho2000 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Levato1975 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Gutierrez-Moreno1968 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference Samus2017 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Evans1966 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Thackera1965 was invoked but never defined (see the help page).
  9. ^ a b c d e f g h i Cite error: The named reference Howe2009 was invoked but never defined (see the help page).
  10. ^ a b c d e Cite error: The named reference Kraicheva1980 was invoked but never defined (see the help page).
  11. ^ a b c Cite error: The named reference Tetzlaff2011 was invoked but never defined (see the help page).
  12. ^ a b c d e f g Cite error: The named reference Vansina1982 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference Gould1879 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference Schmidt-Kaler1982 was invoked but never defined (see the help page).
  16. ^ Cite error: The named reference Buscombe1960 was invoked but never defined (see the help page).