 𝜈 Draconis in optical light | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Draco |
| 𝜈 Dra | |
| Right ascension | 17 32 10.56856 |
| Declination | +55° 11′ 03.2739″ |
| Apparent magnitude (V) | +4.88 |
| 𝜈 Dra | |
| Right ascension | 17 32 16.02464 |
| Declination | +55° 10′ 22.6504″ |
| Apparent magnitude (V) | +4.88 |
| Characteristics | |
| 𝜈 Dra | |
| Spectral type | A8Vm (kA3hF0mF0) |
| U−B color index | +0.03 |
| B−V color index | +0.26 |
| 𝜈 Dra | |
| Spectral type | A4IVm (kA3hF1mF0) |
| U−B color index | +0.04 |
| B−V color index | +0.27 |
| Astrometry | |
| 𝜈 Dra | |
| Radial velocity (Rv) | –15.2 km/s |
| Proper motion (μ) | RA: +147.39 mas/yr Dec.: +54.31 mas/yr |
| Parallax (π) | 33.06 ± 0.15 mas |
| Distance | 98.7 ± 0.4 ly (30.2 ± 0.1 pc) |
| 𝜈 Dra | |
| Radial velocity (Rv) | –16.0 km/s |
| Proper motion (μ) | RA: +142.65 mas/yr Dec.: +62.43 mas/yr |
| Parallax (π) | 32.80 ± 0.18 mas |
| Distance | 99.4 ± 0.5 ly (30.5 ± 0.2 pc) |
| Orbit | |
| Primary | 𝜈 Dra A |
| Companion | 𝜈 Dra B |
| Period (P) | 38.034 days |
| Eccentricity (e) | 0.03 |
| Semi-amplitude (K1) (primary) | 10.0 km/s |
| Details | |
| 𝜈 Dra | |
| Mass | 1.85 M☉ |
| Surface gravity (log g) | 4.2 cgs |
| Temperature | 7,533 K |
| Metallicity | +0.03 |
| Rotational velocity (v sin i) | 86 km/s |
| Age | 13.0 Myr |
| 𝜈 Dra | |
| Mass | 1.61 + 0.24 M☉ |
| Radius | 1.812 R☉ |
| Surface gravity (log g) | 4.11 cgs |
| Temperature | 7,272 K |
| Rotational velocity (v sin i) | 68 km/s |
| Other designations | |
| 𝜈 Draconis, 𝜈 Dra, Kuma | |
| 𝜈 Dra: 24 Dra, BD+55 1944, FK5 655, HD 159541, HIP 85819, HR 6554, SAO 30447 | |
| 𝜈 Dra: 25 Dra, BD+55 1945, FK5 657, HD 159560, HIP 85829, HR 6555, SAO 30450 | |
| Database references | |
| SIMBAD | 𝜈 Dra |
| 𝜈 Dra | |
| 𝜈 Dra | |
Nu Draconis (also known as 𝜈 Dra, 𝜈 Draconis, where 𝜈 is the Greek letter nu, or traditionally as Kuma /ˈkjuːmə/) is a double star in the constellation Draco. The respective components are designated 𝜈 Draconis and 𝜈 Draconis. The second component is a spectroscopic binary star system.
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.
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. Consequently, the Chinese name for 𝜈 Draconis itself is 天棓二 (Tiān Bàng èr, English: the Second Star of Celestial Flail.)
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.
𝜈 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.
𝜈 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. 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.
References
- ^ 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, S2CID 18759600
- ^ 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
- ^ 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. Bibcode:2017AJ....153..218C. doi:10.3847/1538-3881/aa679a.
- ^ Abt, Helmut A; Morrell, Nidia I (1995). "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars". Astrophysical Journal Supplement. 99: 135. Bibcode:1995ApJS...99..135A. doi:10.1086/192182.
- ^ 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.
- ^ 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.
- ^ A.Tokovinin. "Multiple Star Catalog". Archived from the original on 2020-10-03. Retrieved 2018-04-24.
- ^ Soubiran, Caroline; Le Campion, Jean-François; Brouillet, Nathalie; Chemin, Laurent (2016). "The PASTEL catalogue: 2016 version". Astronomy & Astrophysics. 591: A118. arXiv:1605.07384. Bibcode:2016A&A...591A.118S. doi:10.1051/0004-6361/201628497. S2CID 119258214.
- ^ 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, arXiv:astro-ph/0205255, Bibcode:2002A&A...393..897R, doi:10.1051/0004-6361:20020943, S2CID 14070763
- Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (2011). "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun". Monthly Notices of the Royal Astronomical Society. 410 (1): 190–200. arXiv:1007.4883. Bibcode:2011MNRAS.410..190T. doi:10.1111/j.1365-2966.2010.17434.x. S2CID 118629873. Vizier catalog entry
- Masana, E; Jordi, C; Ribas, I (2006). "Effective temperature scale and bolometric corrections from 2MASS photometry". Astronomy & Astrophysics. 450 (2): 735. arXiv:astro-ph/0601049. Bibcode:2006A&A...450..735M. doi:10.1051/0004-6361:20054021. S2CID 15278668.
- 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.
- "24 Dra". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2010-06-04.
- ^ "25 Dra". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2010-06-04.
- 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, retrieved 2010-12-12
- (in 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.
- (in Chinese) 香港太空館 - 研究資源 - 亮星中英對照表 Archived 2011-01-29 at the Wayback Machine, Hong Kong Space Museum. Accessed on line November 23, 2010.
- 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. arXiv:astro-ph/0610605. Bibcode:2007AJ....133..889L. doi:10.1086/510333. S2CID 16800796.
- 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. arXiv:1503.01320. Bibcode:2015MNRAS.449.3160R. doi:10.1093/mnras/stv483. S2CID 119237891.
External links
- Kaler, James. Kuma
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