Omicron Lupi

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Omicron Lupi
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Lupus
Right ascension 14h 51m 38.30289s[1]
Declination −43° 34′ 31.2965″[1]
Apparent magnitude (V) 4.323[2] (4.84 + 5.27)[3]
Spectral type B5 IV[3]
U−B color index −0.620[2]
B−V color index −0.159[2]
Radial velocity (Rv) +7.30±0.74[4] km/s
Proper motion (μ) RA: −25.20[1] mas/yr
Dec.: −27.13[1] mas/yr
Parallax (π) 8.07 ± 0.59[1] mas
Distance 400 ± 30 ly
(124 ± 9 pc)
Absolute magnitude (MV) −1.2±0.3[5]
Mass 5.7±0.2[5] M
Radius 3.5[5] R
Luminosity 1,260[5] L
Surface gravity (log g) 4.1±0.1[5] cgs
Temperature 18,000[6] K
Rotational velocity (v sin i) 25[6] km/s
Other designations
ο Lup, CD−43° 9391, HD 130807, HIP 72683, HR 5528, SAO 225248.[7]
Database references

Omicron Lupi (ο Lup) is a binary star[3] in the southern constellation of Lupus. It is a visible to the naked eye with a combined apparent visual magnitude of 4.323.[2] Based upon an annual parallax shift of 8.07 mas as seen from Earth,[1] it is located around 400 light years from the Sun, give or take 30 light years. At that distance, the visual magnitude of the system is diminished by an extinction factor of 0.13±0.01 due to interstellar dust.[5] It is a member of the Upper Centaurus Lupus[8] subgroup of the nearby Scorpius–Centaurus Association.[6]

This is a visual binary star system with the components having an angular separation of 0.1 arc seconds.[8] The primary, component A, is a magnitude 4.84 B-type subgiant star with a stellar classification of B5 V.[3] It displays radial velocity variations indicating it has an unseen second companion orbiting at a separation of at least 17 AU with a period of 27 years or more.[6] The spectrum of the primary displays a Zeeman effect indicating a magnetic field with a strength ranging from −94 to 677 G.[6] The visible companion, component B, has a visual magnitude of 5.27.[3]


  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 Cousins, A. W. J. (1973), "Revised zero points and UBV photometry of stars in the Harvard E and F regions", Memoirs of the Royal Astronomical Society, 77: 223–236, Bibcode:1973MmRAS..77..223C. 
  3. ^ a b c d e Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878Freely accessible, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x. 
  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. ^ a b c d e f Petit, V.; et al. (February 2013), "A magnetic confinement versus rotation classification of massive-star magnetospheres", Monthly Notices of the Royal Astronomical Society, 429 (1): 398−422, arXiv:1211.0282Freely accessible, Bibcode:2013MNRAS.429..398P, doi:10.1093/mnras/sts344. 
  6. ^ a b c d e Alecian, E.; et al. (December 2011), "First HARPSpol discoveries of magnetic fields in massive stars", Astronomy & Astrophysics, 536: 4, arXiv:1111.3433Freely accessible, Bibcode:2011A&A...536L...6A, doi:10.1051/0004-6361/201118354, L6. 
  7. ^ "omi Lup -- Star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2017-03-10. 
  8. ^ a b Chen, Christine H.; et al. (September 2012), "A Spitzer MIPS Study of 2.5-2.0 M Stars in Scorpius-Centaurus", The Astrophysical Journal, 756 (2): 24, arXiv:1207.3415Freely accessible, Bibcode:2012ApJ...756..133C, doi:10.1088/0004-637X/756/2/133, 133.