Nu Draconis

ν¹/ν² Draconis

Observation data Epoch J2000      Equinox J2000
Constellation	Draco
ν^1 Dra
Right ascension	17^h 32^m 10.56856^s[1]
Declination	+55° 11′ 03.2739″[1]
Apparent magnitude (V)	+4.88[2]
ν^2 Dra
Right ascension	17^h 32^m 16.02464^s[1]
Declination	+55° 10′ 22.6504″[1]
Apparent magnitude (V)	+4.88[2]
Characteristics
Spectral type	A6 V[3] + A4m[4]
U−B color index	+0.03/+0.04[2]
B−V color index	+0.26/+0.27[2]
Astrometry
ν^1 Dra
Radial velocity (Rv)	–15.2[5] 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
Distance	98.7 ± 0.4 ly (30.2 ± 0.1 pc)
ν^2 Dra
Radial velocity (Rv)	–16.0[5] 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
Distance	99.4 ± 0.5 ly (30.5 ± 0.2 pc)
Details
ν^1 Dra
Rotational velocity (v sin i)	86[6] km/s
ν^2 Dra
Rotational velocity (v sin i)	68[6] km/s
Other designations
ν Draconis, ν Dra, Kuma ν^1 Dra: 24 Dra, BD+55 1944, FK5 655, HD 159541, HIP 85819, HR 6554, SAO 30447.[3] ν^2 Dra: 25 Dra, BD+55 1945, FK5 657, HD 159560, HIP 85829, HR 6555, SAO 30450.[4]

Nu Draconis (also known as ν Dra, ν Draconis, or Kuma) 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.^[4]

This star, along with β Dra (Rastaban), γ Dra (Eltanin), μ Dra (Erakis) and ξ Dra (Grumium) were Al ʽAwāïd, "the Mother Camels", which was later known as the Quinque Dromedarii.^[7]

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.^[8] Consequently, ν Draconis itself is known as 天棓二 (Tiān Bàng èr, English: the Second Star of Celestial Flail.)^[9]

References

1. van Leeuwen, F. (November 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
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. "24 Dra -- Star in double system", SIMBAD Astronomical Object Database (Centre de Données astronomiques de Strasbourg), retrieved 2010-06-04
4. "25 Dra -- Spectroscopic binary", SIMBAD Astronomical Object Database (Centre de Données astronomiques de Strasbourg), retrieved 2010-06-04
5. Wilson, Ralph Elmer (1953), General Catalogue of Stellar Radial Velocities, Washington: Carnegie Institution of Washington, Bibcode:1953QB901.W495.....
6. 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: 897–911, arXiv:astro-ph/0205255, Bibcode:2002A&A...393..897R, doi:10.1051/0004-6361:20020943
7. Allen, R. H. (1963), Star Names: Their Lore and Meaning (Reprint ed.), New York, NY: Dover Publications Inc, p. 207, ISBN 0-486-21079-0, retrieved 2010-12-12
8. (Chinese) 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.
9. (Chinese) 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.

External links

• Kaler, James. Kuma