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 𝜈1 Draconis and 𝜈2 Draconis. The second component is a spectroscopic binary star system.[14]
 𝜈 Draconis in optical light | |
| Observation data Epoch J2000 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 | |
| Spectral type | A8Vm[3] (kA3hF0mF0[4]) |
| U−B color index | +0.03[2] |
| B−V color index | +0.26[2] |
| 𝜈2 Dra | |
| Spectral type | A4IVm[3] (kA3hF1mF0[4]) |
| U−B color index | +0.04[2] |
| B−V color index | +0.27[2] |
| Astrometry | |
| 𝜈1 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 mas[1] |
| Distance | 98.7 ± 0.4 ly (30.2 ± 0.1 pc) |
| 𝜈2 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 mas[1] |
| Distance | 99.4 ± 0.5 ly (30.5 ± 0.2 pc) |
| Orbit[6] | |
| Primary | 𝜈2 Dra A |
| Companion | 𝜈2 Dra B |
| Period (P) | 38.034 days |
| Eccentricity (e) | 0.03 |
| Semi-amplitude (K1) (primary) | 10.0 km/s |
| Details | |
| 𝜈1 Dra | |
| Mass | 1.85[7] M☉ |
| Surface gravity (log g) | 4.2[8] cgs |
| Temperature | 7,533[8] K |
| Metallicity | +0.03[8] |
| Rotational velocity (v sin i) | 86[9] km/s |
| Age | 13.0[10] Myr |
| 𝜈2 Dra | |
| Mass | 1.61 + 0.24[7] M☉ |
| Radius | 1.812[11] R☉ |
| Surface gravity (log g) | 4.11[12] cgs |
| Temperature | 7,272[8] K |
| Rotational velocity (v sin i) | 68[9] km/s |
| Other designations | |
𝜈 Draconis, 𝜈 Dra, Kuma | |
| 𝜈1 Dra: 24 Dra, BD+55 1944, FK5 655, HD 159541, HIP 85819, HR 6554, SAO 30447[13] | |
| 𝜈2 Dra: 25 Dra, BD+55 1945, FK5 657, HD 159560, HIP 85829, HR 6555, SAO 30450[14] | |
| Database references | |
| SIMBAD | 𝜈 Dra |
| 𝜈1 Dra | |
| 𝜈2 Dra | |
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.[15]
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.[16] Consequently, the Chinese name for 𝜈 Draconis itself is 天棓二 (Tiān Bàng èr, English: the Second Star of Celestial Flail.)[17]
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.[18]
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.[4]
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.[19][6] 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.[7]
References
edit- ^ a b c d e f g h i j 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
- ^ a b c d e f 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
- ^ a b 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.
- ^ a b c 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.
- ^ a b 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.
- ^ a b 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 b c A.Tokovinin. "Multiple Star Catalog". Archived from the original on 2020-10-03. Retrieved 2018-04-24.
- ^ a b c d 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.
- ^ a b 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.
- ^ a b "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
edit- Kaler, James. Kuma