Delta Serpentis

Delta Serpentis, Latinized from δ Serpentis, is a binary star system system in the constellation Serpens, in its head (Serpens Caput). The light from the two stars in the system give a combined apparent magnitude of +3.80,[2] which is bright enough to be visible to the naked eye. Based on parallax measurements, it is located at a distance of approximately 230 light years from the Sun.[1] The system is moving closer with a radial velocity of −42 km/s, and may come to within 115 light-years in 1.2 million years.[2]

Delta Serpentis
Observation data
Epoch J2000      Equinox J2000
Constellation Serpens
Right ascension 15h 34m 48.14762s[1]
Declination +10° 32′ 19.9248″[1]
Apparent magnitude (V) 3.80[2] (4.25 + 5.2)[3]
Characteristics
Spectral type A9V + A7V[3]
B−V color index 0.268±0.008[2]
Variable type δ Sct (A)
Astrometry
Radial velocity (Rv)−41.5±2.7[2] km/s
Proper motion (μ) RA: −71.48±0.91[1] mas/yr
Dec.: 3.64±0.64[1] mas/yr
Parallax (π)14.30 ± 0.75[1] mas
Distance230 ± 10 ly
(70 ± 4 pc)
Absolute magnitude (MV)−0.42[2]
Details
A
Mass1.58[4] M☉
Radius3[5] R☉
Luminosity24.5[5] L☉
Surface gravity (log g)3.87[4] cgs
Temperature7,649±260[4] K
Rotational velocity (v sin i)77.4[5] km/s
Age433[4] Myr
Other designations
del Ser, 13 Serpentis, BD+11°2821, HIP 76276, ADS 9701, WDS 15348+1032[6]
A: GC 20942, HD 138918, HR 5789
B: GC 20941, HD 138917, HR 5788
Database references
SIMBADdata

The primary, component A, is a yellow-white F-type subgiant with an apparent magnitude of +4.25. It is classified as a Delta Scuti type variable star and its magnitude varies by 0.04 with a period of 0.1557 days.[7] Its binary companion, component B, is also a F-type subgiant which is slightly dimmer, with a magnitude of +5.2. A and B are separated by four arcseconds on the sky,[8] and perform one orbit around their centre of mass once every 3200 years.

Naming

It was a member of indigenous Arabic asterism al-Nasaq al-Yamānī, "the Southern Line" of al-Nasaqān "the Two Lines",[9] along with α Ser (Unukalhai), ε Ser (Ba, Pa), δ Oph (Yed Prior), ε Oph (Yed Posterior), ζ Oph (Han) and γ Oph (Tsung Ching).[10]

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 α Ser, δ Oph, ε Oph, ζ Oph and γ Oph)[11]

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 Serpentis, β Herculis, γ Herculis, κ Herculis, γ Serpentis, β Serpentis, α Serpentis, ε Serpentis, δ Ophiuchi, ε Ophiuchi and ζ Ophiuchi.[12] Consequently, the Chinese name for δ Serpentis itself is 天市右垣六 (Tiān Shì Yòu Yuán liù, English: the Sixth Star of Right Wall of Heavenly Market Enclosure), represent the state Qin (秦) (or Tsin),[13][14][15] together with θ Capricorni and 30 Capricorni (according to Ian Ridpath version[16]) in Twelve States (asterism).[17]

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. S2CID 18759600.
  2. Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. S2CID 119257644.
  3. Fossati, L.; et al. (July 2008). "Abundance analysis of seven δ Scuti stars". Astronomy and Astrophysics. 485 (1): 257–265. arXiv:0804.2402. Bibcode:2008A&A...485..257F. doi:10.1051/0004-6361:200809541. S2CID 8543459.
  4. David, Trevor J.; Hillenbrand, Lynne A. (2015). "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets". The Astrophysical Journal. 804 (2): 146. arXiv:1501.03154. Bibcode:2015ApJ...804..146D. doi:10.1088/0004-637X/804/2/146. S2CID 33401607.
  5. Massarotti, Alessandro; et al. (January 2008). "Rotational and Radial Velocities for a Sample of 761 HIPPARCOS Giants and the Role of Binarity". The Astronomical Journal. 135 (1): 209–231. Bibcode:2008AJ....135..209M. doi:10.1088/0004-6256/135/1/209.
  6. "del Ser". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-07-11.
  7. Rodríguez, E.; et al. (June 2000). "A revised catalogue of delta Sct stars". Astronomy and Astrophysics Supplement. 144 (3): 469–474. Bibcode:2000A&AS..144..469R. doi:10.1051/aas:2000221.
  8. Mason, Brian D.; et al. (2001). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog". The Astronomical Journal. 122 (6): 3466–3471. Bibcode:2001AJ....122.3466M. doi:10.1086/323920. ISSN 0004-6256.
  9. 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 1-931559-44-9.
  10. Allen, R. H. (1963). Star Names: Their Lore and Meaning (Reprint ed.). New York, NY: Dover Publications Inc. p. 243. ISBN 0-486-21079-0. Retrieved 2010-12-12.
  11. Rhoads, Jack W. (November 15, 1971). "Technical Memorandum 33-507-A Reduced Star Catalog Containing 537 Named Stars" (PDF). California Institute of Technology: Jet Propulsion Laboratory.
  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.
  13. Star Names - R.H.Allen p.376
  14. (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 24 日
  15. (in Chinese) English-Chinese Glossary of Chinese Star Regions, Asterisms and Star Name Archived August 10, 2010, at the Wayback Machine, Hong Kong Space Museum. Accessed on line November 23, 2010.
  16. Ridpath, Ian. "Startales - Capricornus the Sea Goat".
  17. Allen, R. H. "Star Names". p. 142.
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