Astronomy:Nu Draconis

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Short description: Star system in the constellation Draco
ν Draconis
Location of ν Draconis (circled in red)
Observation data
{{#ifeq:J2000|J2000.0 (ICRS)|Epoch J2000.0      Equinox J2000.0 (ICRS)| Epoch J2000      [[Astronomy:Equinox (celestial coordinates)|Equinox J2000}}
Constellation Draco
ν1 Dra
Right ascension  17h 32m 10.56856s[1]
Declination +55° 11′ 03.2739″[1]
Apparent magnitude (V) +4.88[2]
ν2 Dra
Right ascension  17h 32m 16.02464s[1]
Declination +55° 10′ 22.6504″[1]
Apparent magnitude (V) +4.88[2]
Characteristics
ν1 Dra
Evolutionary stage main sequence[3]
Spectral type A8Vm[4] (kA3hF0mF0[5])
U−B color index +0.03[2]
B−V color index +0.26[2]
ν2 Dra
Evolutionary stage main sequence[6]
Spectral type A4IVm[4] (kA3hF1mF0[5])
U−B color index +0.04[2]
B−V color index +0.27[2]
Astrometry
ν1 Dra
Radial velocity (Rv)−15.2[7] km/s
Proper motion (μ) RA: +147.39[1] mas/yr
Dec.: +54.31[1] mas/yr
Parallax (π)33.06 ± 0.15[1] mas
Distance98.7 ± 0.4 ly
(30.2 ± 0.1 pc)
ν2 Dra
Radial velocity (Rv)−16.0[7] km/s
Proper motion (μ) RA: +142.65[1] mas/yr
Dec.: +62.43[1] mas/yr
Parallax (π)32.80 ± 0.18[1] mas
Distance99.4 ± 0.5 ly
(30.5 ± 0.2 pc)
Orbit[8]
Period (P)38.034 days
Eccentricity (e)0.03
Semi-amplitude (K1)
(primary)		10.0 km/s
Details
ν1 Dra
Mass1.85[9] M☉
Radius1.8[3] R☉
Luminosity8.1[3] L☉
Surface gravity (log g)4.2[10] cgs
Temperature7,533[10] K
Metallicity+0.03[10]
Rotational velocity (v sin i)86[11] km/s
Age1.0[3] Gyr
ν2 Dra
Mass1.61 + 0.24[9] M☉
Radius1.812[12] R☉
Surface gravity (log g)4.11[13] cgs
Temperature7,272[10] K
Rotational velocity (v sin i)68[11] km/s
Age1.2[6] Gyr
Other designations
ν Draconis, ν Dra, Kuma
ν1 Dra: 24 Dra, BD+55 1944, FK5 655, HD 159541, HIP 85819, HR 6554, SAO 30447[14]
ν2 Dra: 25 Dra, BD+55 1945, FK5 657, HD 159560, HIP 85829, HR 6555, SAO 30450[15]
Database references
SIMBADν Dra
ν1 Dra
ν2 Dra

Nu Draconis (also known as ν Dra, ν Draconis, where ν is the Greek letter nu, or as Kuma /ˈkjuːmə/) is a double star in the constellation Draco. The respective components are designated ν1 Draconis and ν2 Draconis. The second component is a spectroscopic binary star system.[15]

This star, along with β Dra (Rastaban), γ Dra (Eltanin), μ Dra (Alrakis) and ξ Dra (Grumium) were Al ʽAwāïd, "the Mother Camels", which was later known as the Quinque Dromedarii.[16]

ν Draconis in optical light

In Chinese, 天棓 (Tiān Bàng), meaning Celestial Flail, refers to an asterism consisting of ν Draconis, ξ Draconis, β Draconis, γ Draconis and ι Herculis.[17] Consequently, the Chinese name for ν Draconis itself is 天棓二 (Tiān Bàng èr, English: the Second Star of Celestial Flail.)[18] The name Kuma was among the 14 names originating from Antonín Bečvář's 1948 Skalnate Pleso Atlas of the Heavens.[19] James B. Kaler notes that Kuma is of "obscure origin" and noting that one source had postulated it meant "at last".[20]

The two stars of the visual binary are considered to be a common proper motion pair on the basis of their very similar parallaxes, radial velocities, and proper motions, although no orbital motion can be observed.[21]

ν1 Draconis is an Am star, a slowly rotating chemically peculiar star with abnormally strong metallic absorption lines in its spectrum. Its spectral type of kA3hF0mF0 means that it would have a spectral class of A3 if determined solely from its calcium K lines, F0 if determined from its hydrogen lines, and F0 if determined from other metallic spectral lines.[5]

ν2 Draconis is a spectroscopic binary with a period of 38 days. The two stars are separated by 0.267 au on average, and they have an almost circular orbit with an eccentricity of 0.03.[22][8] The primary is also an Am star, while the secondary has a low mass and luminosity and is only inferred from the orbital movement of the more massive star.[9]

References

  1. ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 van Leeuwen, F. (November 2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics 474 (2): 653–664. doi:10.1051/0004-6361:20078357. Bibcode: 2007A&A...474..653V. 
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 Johnson, H. L. et al. (1966). "UBVRIJKL photometry of the bright stars". Communications of the Lunar and Planetary Laboratory 4 (99): 99. Bibcode: 1966CoLPL...4...99J.  PDF
  3. ↑ 3.0 3.1 3.2 3.3 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  4. ↑ 4.0 4.1 Chen, P. S; Liu, J. Y; Shan, H. G (2017). "A New Photometric Study of Ap and Am Stars in the Infrared". The Astronomical Journal 153 (5): 218. doi:10.3847/1538-3881/aa679a. Bibcode: 2017AJ....153..218C. 
  5. ↑ 5.0 5.1 5.2 Abt, Helmut A; Morrell, Nidia I (1995). "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars". Astrophysical Journal Supplement 99: 135. doi:10.1086/192182. Bibcode: 1995ApJS...99..135A. 
  6. ↑ 6.0 6.1 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  7. ↑ 7.0 7.1 Wilson, Ralph Elmer (1953). "General Catalogue of Stellar Radial Velocities". Carnegie Institute Washington D.C. Publication (Washington: Carnegie Institution of Washington). Bibcode: 1953GCRV..C......0W. 
  8. ↑ 8.0 8.1 Margoni, R; Munari, U; Stagni, R (1992). "Spectroscopic orbits of AM stars. I - Seven field stars". Astronomy and Astrophysics Supplement Series 93: 545. Bibcode: 1992A&AS...93..545M. 
  9. ↑ 9.0 9.1 9.2 A.Tokovinin. "Multiple Star Catalog". http://www.ctio.noao.edu/~atokovin/stars/stars.php?cat=HIP&number=85819. 
  10. ↑ 10.0 10.1 10.2 10.3 Soubiran, Caroline; Le Campion, Jean-François; Brouillet, Nathalie; Chemin, Laurent (2016). "The PASTEL catalogue: 2016 version". Astronomy & Astrophysics 591: A118. doi:10.1051/0004-6361/201628497. Bibcode: 2016A&A...591A.118S. 
  11. ↑ 11.0 11.1 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 (3): 897–911. doi:10.1051/0004-6361:20020943. Bibcode: 2002A&A...393..897R. 
  12. ↑ Masana, E; Jordi, C; Ribas, I (2006). "Effective temperature scale and bolometric corrections from 2MASS photometry". Astronomy & Astrophysics 450 (2): 735. doi:10.1051/0004-6361:20054021. Bibcode: 2006A&A...450..735M. 
  13. ↑ Stateva, I.; Belcheva, M.; Iliev, I. Kh.; Budaj, J.; Barzova, I.S. (April 2008). "Chemical abundances study of three Am stars HD155375, HD159560 and HD196544". Contributions of the Astronomical Observatory Skalnaté Pleso 38 (2): 455–456. Bibcode: 2008CoSka..38..455S. 
  14. ↑ "24 Dra". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=24+Dra. 
  15. ↑ 15.0 15.1 "25 Dra". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=25+Dra. 
  16. ↑ Allen, R. H. (1963). Star Names: Their Lore and Meaning (Reprint ed.). New York, NY: Dover Publications Inc. p. 207. ISBN 978-0-486-21079-7. https://archive.org/details/starnamestheirlo00alle/page/207. Retrieved 2010-12-12. 
  17. ↑ Script error: The function "in_lang" does not exist. 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 978-986-7332-25-7.
  18. ↑ Script error: The function "in_lang" does not exist. 香港太空館 - 研究資源 - 亮星中英對照表 , Hong Kong Space Museum. Accessed on line November 23, 2010.
  19. ↑ Reilly, Doug (17 January 2013). "Star Atlas Mystery: The Bečvář 14". http://bicycleastronomy.org/2013/01/17/star-atlas-mystery-the-becvar-14/. 
  20. ↑ Kaler, Jim. "Kuma". University of Illinois. http://stars.astro.illinois.edu/sow/kuma.html. 
  21. ↑ Lépine, Sébastien; Bongiorno, Bethany (2007). "New Distant Companions to Known Nearby Stars. II. Faint Companions of Hipparcos Stars and the Frequency of Wide Binary Systems". The Astronomical Journal 133 (3): 889–905. doi:10.1086/510333. Bibcode: 2007AJ....133..889L. 
  22. ↑ Rodriguez, David R; Duchêne, Gaspard; Tom, Henry; Kennedy, Grant M; Matthews, Brenda; Greaves, Jane; Butner, Harold (2015). "Stellar multiplicity and debris discs: An unbiased sample". Monthly Notices of the Royal Astronomical Society 449 (3): 3160. doi:10.1093/mnras/stv483. Bibcode: 2015MNRAS.449.3160R. 




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