Astronomy:Nu Leonis

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Short description: Binary star system in the constellation Leo
ν Leonis
Leo constellation map.svg
Red circle.svg
Location of ν Leonis (circled)
Observation data
Epoch J2000.0   Equinox (celestial coordinates)
Constellation Leo
Right ascension  09h 58m 13.37557s[1]
Declination +12° 26′ 41.2865″[1]
Apparent magnitude (V) 5.15[2]
Characteristics
Spectral type B6 IV[3]
U−B color index −0.13[2]
B−V color index −0.04[2]
Astrometry
Radial velocity (Rv)+14.4[4] km/s
Proper motion (μ) RA: −25.66[1] mas/yr
Dec.: −15.56[1] mas/yr
Parallax (π)6.53 ± 0.24[1] mas
Distance500 ± 20 ly
(153 ± 6 pc)
Absolute magnitude (MV)−0.66[5]
Orbit[6]
Period (P)137.2978 d
Eccentricity (e)0.7
Longitude of the node (Ω)293.7°
Periastron epoch (T)2419815.9 JD
Semi-amplitude (K1)
(primary)
20 km/s
Details
Mass3.37±0.05[7] M
Radius2.3[8] R
Luminosity244[7] L
Temperature9,552[9] K
Rotational velocity (v sin i)100[7] km/s
Other designations
ν Leo, 27 Leo, BD+13°2183, HD 86360, HIP 48883, HR 3937, SAO 98876[10]
Database references
SIMBADdata

ν Leonis, Latinised as Nu Leonis, is a binary star system in the zodiac constellation of Leo. It is faintly visible to the naked eye with an apparent visual magnitude of 5.15;[2] parallax measurements[1] indicate it is around 500 light years away. At this distance, the visual extinction from interstellar dust is 0.33 magnitudes.[11]

It is 0.05 degree north of the ecliptic, so it can be occulted by the moon or planets.

This is a single-lined spectroscopic binary system with an orbital period of 137.3 days and an eccentricity of 0.7.[6] The primary component is a B-type subgiant star with a stellar classification of B6 IV.[3] It has about 3.37 times the mass of the Sun,[7] 2.3 times the Sun's radius,[8] and radiates 244[7] times the luminosity of the Sun from an outer atmosphere with an effective temperature of 9,552 K.[9] The rotation rate is moderate with a projected rotational velocity of 100 km/s.[7] Little is known about the companion.[6]

References

  1. 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode2007A&A...474..653V. 
  2. 2.0 2.1 2.2 2.3 Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data (SIMBAD), Bibcode1986EgUBV........0M. 
  3. 3.0 3.1 Cowley, A. et al. (April 1969), "A study of the bright A stars. I. A catalogue of spectral classifications", Astronomical Journal 74: 375–406, doi:10.1086/110819, Bibcode1969AJ.....74..375C. 
  4. Evans, D. S. (June 20–24, 1966), "The Revision of the General Catalogue of Radial Velocities", in Batten, Alan Henry; Heard, John Frederick, Determination of Radial Velocities and their Applications, Proceedings of IAU Symposium no. 30, 30, University of Toronto: International Astronomical Union, p. 57, Bibcode1967IAUS...30...57E. 
  5. Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode2012AstL...38..331A. 
  6. 6.0 6.1 6.2 Harmanec, P. et al. (May 1985), "A spectroscopic orbit of the late B star 27 Leo", Bulletin Astronomical Institutes of Czechoslovakia 36: 160–172, Bibcode1985BAICz..36..160H. 
  7. 7.0 7.1 7.2 7.3 7.4 7.5 Zorec, J.; Royer, F. (January 2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics 537: A120, doi:10.1051/0004-6361/201117691, Bibcode2012A&A...537A.120Z. 
  8. 8.0 8.1 Pasinetti Fracassini, L. E. et al. (2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) – Third edition – Comments and statistics", Astronomy & Astrophysics 367 (2): 521–24, doi:10.1051/0004-6361:20000451, Bibcode2001A&A...367..521P. 
  9. 9.0 9.1 McDonald, I. et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society 427 (1): 343–57, doi:10.1111/j.1365-2966.2012.21873.x, Bibcode2012MNRAS.427..343M. 
  10. "* nu. Leo". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=%2A+nu.+Leo. 
  11. van Belle, Gerard T.; von Braun, Kaspar (2009), "Directly Determined Linear Radii and Effective Temperatures of Exoplanet Host Stars", The Astrophysical Journal 694 (2): 1085–1098, doi:10.1088/0004-637X/694/2/1085, Bibcode2009ApJ...694.1085V.