Zeta Coronae Borealis

ζ Coronae Borealis , Latinised as Zeta Coronae Borealis, is the Bayer designation of a double star in the constellation Corona Borealis. The two components are separated by six arc-seconds and share the same Hipparcos catalogue number and Flamsteed designation. Each of the two is also a spectroscopic multiple system, with a total of five stars in the group.

ζ Coronae Borealis
Location of ζ Coronae Borealis (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Corona Borealis
ζ1
Right ascension 15h 39m 22.247s[1]
Declination +36° 38′ 12.42″[1]
Apparent magnitude (V) 5.95[2]
ζ2
Right ascension 15h 39m 22.668s[1]
Declination +36° 38′ 08.78″[1]
Apparent magnitude (V) 4.99[2]
Characteristics
ζ1
Evolutionary stage Main sequence
Spectral type B9 V[2]
ζ2
Evolutionary stage Main sequence
Spectral type B6 V + B7 V[2]
Astrometry
ζ1
Radial velocity (Rv)−19.4[3] km/s
Proper motion (μ) RA: −14.199±0.093[4] mas/yr
Dec.: −3.871±0.128[4] mas/yr
Parallax (π)6.2190 ± 0.0685[4] mas
Distance524 ± 6 ly
(161 ± 2 pc)
ζ2
Radial velocity (Rv)−24.3[3] km/s
Proper motion (μ) RA: −15.624±0.273[5] mas/yr
Dec.: −7.310±0.342[5] mas/yr
Parallax (π)6.6433 ± 0.1841[5] mas
Distance490 ± 10 ly
(151 ± 4 pc)
Orbit[6]
Primaryζ2A
Companionζ2 B
Period (P)1.72357 days
Eccentricity (e)0.013
Inclination (i)38°
Semi-amplitude (K1)
(primary)		109.6 km/s
Semi-amplitude (K2)
(secondary)		121.2 km/s
Orbit
Primaryζ2 AB
Companionζ2 C
Period (P)251.5 days
Eccentricity (e)0.48
Semi-amplitude (K1)
(primary)		28.5 km/s
Details
ζ1 A
Mass3.19[7] M☉
Rotational velocity (v sin i)15[8] km/s
ζ2 A
Mass4.13[9] M☉
Rotation1.7 days[9]
Rotational velocity (v sin i)46±7[9] km/s
ζ2 B
Mass3.73[9] M☉
Rotational velocity (v sin i)7.5±2[9] km/s
ζ2 C
Mass3.78[9] M☉
Other designations
7 Coronae Borealis, HIP 76669, BD+37°2665, CCDM J15394+3638, WDS J15394+3638
ζ1: HR 5833, HD 139891
ζ2: HR 5834, HD 139892
Database references
SIMBADζ
ζ1
ζ2

Nomenclature

ζ Coronae Borealis has the Flamsteed designation 7 Coronae Borealis and the Hipparcos catalogue number HIP 76669. As a double star, the brighter component is designated A (e.g. WDS J15394+3638 A) while the fainter of the two is designated B. The brighter star is also known as ζ2 Coronae Borealis and the fainter as ζ1 Coronae Borealis.

Each of the pair has its own Bright Star Catalogue and Henry Draper Catalogue numbers: HR 5833 and 5834, and HD 139891 and 139892 for ζ1 and ζ2 respectively.

System

ζ1 Coronae Borealis is a single-lined spectroscopic binary, with an orbital period of about 9.5 days. The nature of the companion is unknown.[7]

The brighter star, ζ2 Coronae Borealis, is a spectroscopic triple system, consisting of three massive stars. The inner pair orbit in 1.7 days, while the outer pair orbit in 251 days.[7]

References
  1. Cutri, R. M.; Skrutskie, M. F.; Van Dyk, S.; Beichman, C. A.; Carpenter, J. M.; Chester, T.; Cambresy, L.; Evans, T.; Fowler, J.; Gizis, J.; Howard, E.; Huchra, J.; Jarrett, T.; Kopan, E. L.; Kirkpatrick, J. D.; Light, R. M.; Marsh, K. A.; McCallon, H.; Schneider, S.; Stiening, R.; Sykes, M.; Weinberg, M.; Wheaton, W. A.; Wheelock, S.; Zacarias, N. (2003). "VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)". VizieR On-line Data Catalog: II/246. Originally Published in: 2003yCat.2246....0C. 2246. Bibcode:2003yCat.2246....0C.
  2. Eggleton, P. P.; Tokovinin, A. A. (2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society. 389 (2): 869. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x.
  3. Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Washington: 0. Bibcode:1953GCRV..C......0W.
  4. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  5. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  6. Gordon, K. D.; Mulliss, C. L. (1997). "Zeta$^2$ Coronae Borealis, A Spectroscopic Triple System Including an Asynchronous Close Binary". Publications of the Astronomical Society of the Pacific. 109: 221. arXiv:astro-ph/9611090. Bibcode:1997PASP..109..221G. doi:10.1086/133877.
  7. "Multiple Star Catalogue". Retrieved 2018-11-23.
  8. Abt, Helmut A.; Levato, Hugo; Grosso, Monica (2002). "Rotational Velocities of B Stars". The Astrophysical Journal. 573 (1): 359. Bibcode:2002ApJ...573..359A. doi:10.1086/340590.
  9. Tokovinin, A. (2008). "Comparative statistics and origin of triple and quadruple stars". Monthly Notices of the Royal Astronomical Society. 389 (2): 925–938. arXiv:0806.3263. Bibcode:2008MNRAS.389..925T. doi:10.1111/j.1365-2966.2008.13613.x.
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