Nu2 Boötis

Nu2 Boötis is a white-hued binary star[10] system in the northern constellation of Boötes. It is faintly visible to the naked eye with a combined apparent visual magnitude of 5.02.[2] Based upon an annual parallax shift of 7.86 mas as seen from the Earth[1], it is located roughly 415 light years from the Sun. The system is moving closer to the Sun with a radial velocity of −16.6 km/s.[5]

For other stars with this Bayer designation, see ν Boötis.
Nu2 Boötis

ν1 (right) and ν2 (left) Boötis in optical light
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Boötes
Right ascension  15h 31m 46.98170s[1]
Declination +40° 53′ 57.5405″[1]
Apparent magnitude (V) 5.02[2] (5.80 + 5.80)[3]
Characteristics
Spectral type A5 V[4]
U−B color index +0.11[2]
B−V color index +0.07[2]
R−I color index 0.04
Astrometry
Radial velocity (Rv)−16.6±3.7[5] km/s
Proper motion (μ) RA: -21.905[1] mas/yr
Dec.: -7.876[1] mas/yr
Parallax (π)7.8618 ± 0.1449[1] mas
Distance415 ± 8 ly
(127 ± 2 pc)
Absolute magnitude (MV)−0.59[6]
Orbit[7]
Period (P)9.026±0.017 yr
Semi-major axis (a)0.0615±0.0007″
Eccentricity (e)0.006±0.015
Inclination (i)109.7±1.2°
Longitude of the node (Ω)199.4±0.9°
Periastron epoch (T)2000.75±0.24
Argument of periastron (ω)
(secondary)		293±9°
Details
Mass2.84±0.11[8] M☉
Luminosity146[8] L☉
Temperature8,472[8] K
Rotational velocity (v sin i)217[8] km/s
Other designations
ν2 Boo, 53 Boötis, BD+41° 2611, GC 20883, HD 138629, HIP 76041, HR 5774, SAO 45590, ADS 9688, CCDM 15318+4054, WDS J15318+4054AB[9]
Database references
SIMBADdata
Data sources:
Hipparcos Catalogue,
CCDM (2002),
Bright Star Catalogue (5th rev. ed.)

This stellar pair have a nearly circular orbit with a period of nine years and a semimajor axis of 0.0615 arc seconds.[10] They are both of visual magnitude 5.80 and display a similar spectrum, with the primary, component A, being an A-type main sequence star with a stellar classification of A5 V.[4] This has been identified as an A-type shell star, suggesting there is a circumstellar disk of gas orbiting one or both stars.[11]

References
  1. 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.
  2. Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99), Bibcode:1966CoLPL...4...99J.
  3. Mason, B. D.; et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal, 122: 3466–3471, Bibcode:2001AJ....122.3466M, doi:10.1086/323920
  4. 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.
  5. 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:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, A61.
  6. 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.
  7. Hartkopf, W. I.; et al. (June 30, 2006), Sixth Catalog of Orbits of Visual Binary Stars, United States Naval Observatory, retrieved 2017-09-13.
  8. Zorec, J.; Royer, F. (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.
  9. "nu02 Boo". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-09-09.
  10. 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:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x.
  11. Hauck, B.; Jaschek, C. (February 2000), "A-shell stars in the Geneva system", Astronomy and Astrophysics, 354: 157–162, Bibcode:2000A&A...354..157H.
  • Hoffleit; et al. (1991), "HR 5774", Bright Star Catalogue (5th Revised ed.), retrieved 2017-09-13.
  • "Nu2 Boötis", Aladin previewer, Centre de Données astronomiques de Strasbourg, retrieved 2017-09-12.
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