Delta Draconis

δ Draconis

Location of δ Draconis (left of center).
Observation data
Epoch J2000      Equinox J2000
Constellation Draco
Right ascension 19h 12m 33.3000s[1]
Declination +67° 39′ 41.549″[1]
Apparent magnitude (V) 3.082
Characteristics
Spectral type G9III[2]
U−B color index +0.78[3]
B−V color index +1.00[3]
Astrometry
Radial velocity (Rv) 24.8[4] km/s
Proper motion (μ) RA: 94.49[1] mas/yr
Dec.: 92.30[1] mas/yr
Parallax (π) 32.54 ± 0.46[1] mas
Distance 100 ± 1 ly
(30.7 ± 0.4 pc)
Details
Radius 11[5] R☉
Surface gravity (log g) 2.98[6]
Luminosity 58 L☉
Temperature 4,820[6] K
Metallicity \begin{smallmatrix}\left[\frac{Fe}{H}\right]\ =\ -0.27\end{smallmatrix}[6]
Rotational velocity (v sin i) 8[7] km/s
Other designations
Aldib, Altais,[8] Nodus Secundus,[9] HR 7310, BD+67 1129, HD 180711, SAO 18222, FK5 723, HIP 94376.[10]

Delta Draconis (δ Dra, δ Draconis) is a yellow star in the constellation Draco. It has the traditional names Aldib, Altais[8] (the goat) and Nodus Secundus.[9]

The title Altais was derived from Arabic Al Tāis, "the Goat", the association of this star, along with π Dra, ρ Dra and ε Dra (Tyl).[11].

According to the catalogue of stars in the Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars, Al Tāis or Tais were the title for three stars :δ Dra as Altais, π Dra as Tais I and ρ Dra as Tais II (exclude ε Dra)[12]

In Chinese, 天廚 (Tiān Chú, Tien Choo), meaning Celestial Kitchen or Heaven's Kitchen, refers to an asterism consisting of δ Draconis, σ Draconis, ε Draconis, ρ Draconis, 64 Draconis and π Draconis.[13] Consequently, δ Draconis itself is known as 天廚一 (Tiān Chú yī, English: the First Star of Celestial Kitchen.)[14]

Structure

Delta Draconis is a giant star with a stellar classification of G9III. At a distance of approximately 100 light years from Earth, it has an apparent magnitude of 3.0. The angular diameter of the star is estimated as 3.37 ± 0.06 mas.[15] At a parallax of 32.54 mas, this corresponds to a physical radius equal to 11 times the solar radius.[5]

References

  1. ^ a b c d e Perryman, M. A. C. et al; Lindegren; Kovalevsky; Hoeg; Bastian; Bernacca; Crézé; Donati et al. (April 1997). "The HIPPARCOS Catalogue". Astronomy & Astrophysics 323: L49–L52. Bibcode 1997A&A...323L..49P. 
  2. ^ Roman, Nancy G. (July 1952). "The Spectra of the Bright Stars of Types F5-K5". Astrophysical Journal 116: 122. Bibcode 1952ApJ...116..122R. doi:10.1086/145598. 
  3. ^ a b Johnson, H. L.; Mitchell; Iriarte; Wisniewski; et al. (1966). "UBVRIJKL photometry of the bright stars". Communications of the Lunar and Planetary Laboratory 4 (99): 99. Bibcode 1966CoLPL...4...99J. 
  4. ^ Wilson, Ralph Elmer (1953). General Catalogue of Stellar Radial Velocities. Washington: Carnegie Institution of Washington. Bibcode 1953QB901.W495...... 
  5. ^ a b The Sun has a radius of 0.004652 AU. Thus:
    Stellar diameter = 1 AU × angular diameter/parallax = 3.37/32.54 AU = 0.10 AU = 22 R☉.
    See: Lochner, Jim; Gibb, Meredith; Newman, Phil (January 30, 2006). "Using Optical Observations to find the Diameter of HT Cas". NASA. http://imagine.gsfc.nasa.gov/YBA/HTCas-size/optical.html. Retrieved 2010-04-06. 
  6. ^ a b c McWilliam, Andrew (December 1990). "High-resolution spectroscopic survey of 671 GK giants. I - Stellar atmosphere parameters and abundances". Astrophysical Journal Supplement Series 74: 1075–1128. Bibcode 1990ApJS...74.1075M. doi:10.1086/191527. 
  7. ^ Bernacca, P. L.; Perinotto, M.; Perinotto (1970). "A catalogue of stellar rotational velocities". Contributi Osservatorio Astronomico di Padova in Asiago 239 (1): 1. Bibcode 1970CoAsi.239....1B. 
  8. ^ a b Bakich, Michael E. (1995). The Cambridge guide to the constellations. Cambridge University Press. p. 184. ISBN 0521449219. 
  9. ^ a b Kaler, James B.. "Nodus Secundus". STARS. University of Illinois. http://stars.astro.illinois.edu/sow/nodus2.html. Retrieved 2010-04-06. 
  10. ^ "del Dra -- Star in double system". SIMBAD. Centre de Données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=del+Dra. Retrieved 2010-04-06. 
  11. ^ Allen, R. H. (1963). Star Names: Their Lore and Meaning (Reprint ed.). New York, NY: Dover Publications Inc. p. 209. ISBN 0486210790. http://penelope.uchicago.edu/Thayer/E/Gazetteer/Topics/astronomy/_Texts/secondary/ALLSTA/Draco*.html. Retrieved 2010-12-12. 
  12. ^ Jack W. Rhoads - Technical Memorandum 33-507-A Reduced Star Catalog Containing 537 Named Stars, Jet Propulsion Laboratory, California Institue of Technology; November 15, 1971
  13. ^ (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 9789867332257.
  14. ^ (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.
  15. ^ Di Benedetto, G. P. (February 2005). "Predicting accurate stellar angular diameters by the near-infrared surface brightness technique". Monthly Notices of the Royal Astronomical Society 357 (1): 174–190. Bibcode 2005MNRAS.357..174D. doi:10.1111/j.1365-2966.2005.08632.x. 
Stars of Draco
Bayer
Flamsteed
Nearby