Delta Ophiuchi

Delta Ophiuchi

Location of δ Ophiuchi (middle right)
Observation data Epoch J2000      Equinox J2000
Constellation	Ophiuchus
Right ascension	16h 14m 20.7395s[1]
Declination	−03° 41′ 39.563″
Apparent magnitude (V)	2.74[2]
Characteristics
Spectral type	M0.5III[3]
U−B color index	+1.96[4]
B−V color index	+1.59[4]
Astrometry
Radial velocity (Rv)	−19.9[5] km/s
Proper motion (μ)	RA: −45.83[1] mas/yr Dec.: −142.91[1] mas/yr
Parallax (π)	19.16 ± 1.02[1] mas
Distance	170 ± 9 ly (52 ± 3 pc)
Details
Surface gravity (log g)	1.4[6]
Temperature	3,679[6] K
Metallicity	$\begin{smallmatrix}\left[\frac{Fe}{H}\right]\ =\ 0.32\end{smallmatrix}$[6]
Other designations
1 Oph, HR 6056, BD-03 3903, HD 146051, SAO 141052, FK5 603, HIP 79593.[2]

Delta Ophiuchi (δ Oph, δ Ophiuchi) is a star in the constellation Ophiuchus. It has the traditional name Yed Prior (and the star Epsilon Ophiuchi, with which it forms a naked eye optical double, is Yed Posterior).

The traditional name Yed is derived from Arabic meaning "the hand", and the two stars are the left hand of Ophiuchus (the Serpent Bearer) that holds the head of the serpent Serpens Caput.

It was a member of the indigenous Arabic asterism al-Nasaq al-Yamānī, "the Southern Line" of al-Nasaqān "the Two Lines".^[7] It was a member of indigenous Arabic asterism al-Nasaq al-Yamānī, "the Southern Line" of al-Nasaqān "the Two Lines".^[8], along with α Ser (Unukalhai), δ Ser (Qin, Tsin), ε Ser (Ba, Pa), ε Oph (Yed Posterior), ζ Oph (Han) and γ Oph (Tsung Ching).^[9]

According to the catalogue of stars in the Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars, al-Nasaq al-Yamānī or Nasak Yamani were the title for two stars :δ Ser as Nasak Yamani I and ε Ser as Nasak Yamani II (exclude this star, α Ser, ε Oph, ζ Oph and γ Oph)^[10]

In Chinese, 天市右垣 (Tiān Shì Yòu Yuán), meaning Right Wall of Heavenly Market Enclosure, refers to an asterism which is represent eleven old states in China which is marking the right borderline of the enclosure, consisting of δ Ophiuchi, β Herculis, γ Herculis, κ Herculis, γ Serpentis, β Serpentis, α Serpentis, δ Serpentis, ε Serpentis, ε Ophiuchi and ζ Ophiuchi ^[11]. Consequently, δ Ophiuchi itself is known as 天市右垣九 (Tiān Shì Yòu Yuán jiǔ, English: the Ninth Star of Right Wall of Heavenly Market Enclosure), represent the state Liang (梁) (or Leang)^[12][13].

Structure

Delta Ophiuchi is 170 light years from Earth, while Epsilon is 108; hence they are a mere optical double. Yed Prior is a red giant (class M) with a temperature of 3,679 K.

References

1. ^ ^{a b c d} Perryman, M. A. C. et al (April 1997). "The HIPPARCOS Catalogue". Astronomy & Astrophysics 323: L49–L52. Bibcode 1997A&A...323L..49P. 
2. ^ ^{a b} "del Oph -- Variable Star". SIMBAD. Centre de Données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=Delta+Ophiuchi. Retrieved 2010-07-06. 
3. ^ Morgan, W. W.; Keenan, P. C. (1973). "Spectral Classification". Annual Review of Astronomy and Astrophysics 11: 29. Bibcode 1973ARA&A..11...29M. doi:10.1146/annurev.aa.11.090173.000333. 
4. ^ ^{a b} Johnson, H. L.; Iriarte, B.; Mitchell, R. I.; Wisniewskj, W. Z. (1966). "UBVRIJKL photometry of the bright stars". Communications of the Lunar and Planetary Laboratory 4 (99). Bibcode 1966CoLPL...4...99J. 
5. ^ Wilson, Ralph Elmer (1953). General Catalogue of Stellar Radial Velocities. Washington: Carnegie Institution of Washington. Bibcode 1953QB901.W495...... 
6. ^ ^{a b c} Oinas, V. (October 1977). "Neutral-ion anomaly in cool stars". Astronomy and Astrophysics 61 (1): 17–20. Bibcode 1977A&A....61...17O. 
7. ^ Kunitzsch, P., Smart, T., (2006). A Dictionary of Modern Star names: A Short Guide to 254 Star names and Their Derivations (Second Revised ed.). Cambridge, MA: Sky Publishing. p. 31. ISBN 1931559449. 
8. ^ Kunitzsch, P., Smart, T., (2006). A Dictionary of Modern Star names: A Short Guide to 254 Star names and Their Derivations (Second Revised ed.). Cambridge, MA: Sky Publishing. p. 31. ISBN 1931559449. 
9. ^ Allen, R. H. (1963). Star Names: Their Lore and Meaning (Reprint ed.). New York, NY: Dover Publications Inc. p. 243. ISBN 0486210790. http://penelope.uchicago.edu/Thayer/E/Gazetteer/Topics/astronomy/_Texts/secondary/ALLSTA/Hercules*.html. Retrieved 2010-12-12. 
10. ^ Jack W. Rhoads - Technical Memorandum 33-507-A Reduced Star Catalog Containing 537 Named Stars, Jet Propulsion Laboratory, California Institute of Technology; November 15, 1971
11. ^ (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.
12. ^ (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.
13. ^ (Chinese) English-Chinese Glossary of Chinese Star Regions, Asterisms and Star Name, Hong Kong Space Museum. Accessed on line November 23, 2010.

External links

• Jim Kaler. "Yed Prior". STARS. http://www.astro.uiuc.edu/~kaler/sow/yedprior.html. Retrieved July 22, 2005.