Nu Leonis
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]
  | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| 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 |
| Distance | 500 ± 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 | |
| Mass | 3.37±0.05[7] M☉ |
| Radius | 2.3[8] R☉ |
| Luminosity | 244[7] L☉ |
| Temperature | 9,552[9] K |
| Rotational velocity (v sin i) | 100[7] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
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
- van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357.
- Mermilliod, J.-C. (1986), Compilation of Eggen's UBV data, transformed to UBV (unpublished), SIMBAD, Bibcode:1986EgUBV........0M.
- Cowley, A.; et al. (April 1969), "A study of the bright A stars. I. A catalogue of spectral classifications", Astronomical Journal, 74: 375–406, Bibcode:1969AJ.....74..375C, doi:10.1086/110819.
- Evans, D. S. (June 20–24, 1966), Batten, Alan Henry; Heard, John Frederick (eds.), The Revision of the General Catalogue of Radial Velocities, University of Toronto: International Astronomical Union, Bibcode:1967IAUS...30...57E.
- Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015.
- Harmanec, P.; et al. (May 1985), "A spectroscopic orbit of the late B star 27 Leo", Bulletin Astronomical Institutes of Czechoslovakia, 36: 160–172, Bibcode:1985BAICz..36..160H.
- Zorec, J.; Royer, F. (January 2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics, 537: A120, arXiv:1201.2052, Bibcode:2012A&A...537A.120Z, doi:10.1051/0004-6361/201117691.
- 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: 521–24, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451.
- 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:1208.2037, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x.
- "* nu. Leo". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2016-09-29.
- 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, arXiv:0901.1206, Bibcode:2009ApJ...694.1085V, doi:10.1088/0004-637X/694/2/1085.