Iota Coronae Borealis

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Iota Coronae Borealis
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Corona Borealis
Right ascension 16h 01m 26.56488s[1]
Declination +29° 51′ 03.8243″[1]
Apparent magnitude (V) 4.96[2]
Spectral type A0 IIIp(HgMnEu)s[3]
U−B color index −0.15[2]
B−V color index −0.06[2]
Radial velocity (Rv)−20.8±0.4[4] km/s
Proper motion (μ) RA: −38.31[1] mas/yr
Dec.: −6.56[1] mas/yr
Parallax (π)10.46 ± 0.24[1] mas
Distance312 ± 7 ly
(96 ± 2 pc)
Absolute magnitude (MV)+0.08[5]
Period (P)35.474 d
Eccentricity (e)0.56
Periastron epoch (T)2441566.96 JD
Argument of periastron (ω)
Semi-amplitude (K1)
2.3 km/s
ι CrB A
Luminosity90[7] L
Surface gravity (log g)3.84±0.16[8] cgs
Temperature10,727±278[8] K
Metallicity [Fe/H]−0.01±0.12[8] dex
Rotational velocity (v sin i)18[9] km/s
Other designations
ι CrB, 14 CrB, BD+30° 2738, HD 143807, HIP 78493, HR 5971, SAO 84152[10]
Database references

Iota Coronae Borealis, Latinized from ι Coronae Borealis, is a binary star[6] system in the constellation Corona Borealis. It is visible to the naked eye with a combined apparent visual magnitude of is 4.96.[2] Based upon an annual parallax shift of 10.46 mas as seen from the Earth,[1] it is located about 312 light years from the Sun.

This is a single-lined spectroscopic binary with an orbital period of 35.5 days and an eccentricity of 0.56.[6] The visible member, component A, has a stellar classification of A0 IIIp(HgMnEu)s,[3] indicating it is a chemically peculiar mercury-manganese star with narrow absorption lines. The secondary member, component B, appears to be an A-type star.[11]


  1. ^ a b c d e f van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752Freely accessible, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357. 
  2. ^ a b c d Fernie, J. D. (1983), "New UBVRI photometry for 900 supergiants", Astrophysical Journal Supplement Series, 52: 7, Bibcode:1983ApJS...52....7F, doi:10.1086/190856. 
  3. ^ a b Abt, Helmut A.; Morrell, Nidia I. (1995), "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars", Astrophysical Journal Supplement, 99: 135, Bibcode:1995ApJS...99..135A, doi:10.1086/192182. 
  4. ^ de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, arXiv:1208.3048Freely accessible, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, A61. 
  5. ^ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971Freely accessible, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015. 
  6. ^ a b c Pourbaix, D.; et al. (2004), "SB9: The ninth catalogue of spectroscopic binary orbits", Astronomy and Astrophysics, 424 (2): 727–732, arXiv:astro-ph/0406573Freely accessible, Bibcode:2004A&A...424..727P, doi:10.1051/0004-6361:20041213. 
  7. ^ McDonald, I.; et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society, 427 (1): 343–57, arXiv:1208.2037Freely accessible, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x 
  8. ^ a b c Prugniel, Ph.; Vauglin, I.; Koleva, M. (July 2011), "The atmospheric parameters and spectral interpolator for the MILES stars", Astronomy & Astrophysics, 531: A165, arXiv:1104.4952Freely accessible, Bibcode:2011A&A...531A.165P, doi:10.1051/0004-6361/201116769. 
  9. ^ Royer, F.; et al. (October 2002), "Rotational velocities of A-type stars in the northern hemisphere. II. Measurement of v sin i", Astronomy and Astrophysics, 393: 897–911, arXiv:astro-ph/0205255Freely accessible, Bibcode:2002A&A...393..897R, doi:10.1051/0004-6361:20020943. 
  10. ^ "iot CrB". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-05-05. 
  11. ^ Dubaj, D.; Monier, R.; Alecian, G.; Leblanc, F. (December 2005), Casoli, F.; Contini, T.; Hameury, J.M.; Pagani, L., eds., "Abundance determinations for the two components of the spectroscopic binary star HD143807", SF2A-2005: Semaine de l'Astrophysique Francaise, EdP-Sciences: 335, Bibcode:2005sf2a.conf..335D.