Epsilon Serpentis
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Serpens |
| Right ascension | 15h 50m 48.96622s[1] |
| Declination | +04° 28′ 39.8311″[1] |
| Apparent magnitude (V) | +3.69[2] |
| Characteristics | |
| Spectral type | kA2hA5mA7 V[3] |
| U−B color index | +0.12[2] |
| B−V color index | +0.14[2] |
| Astrometry | |
| Radial velocity (Rv) | −9.4±0.6[4] km/s |
| Proper motion (μ) | RA: +128.19[1] mas/yr Dec.: +62.16[1] mas/yr |
| Parallax (π) | 46.30 ± 0.19 mas [1] |
| Distance | 70.4 ± 0.3 ly (21.60 ± 0.09 pc) |
| Absolute magnitude (MV) | +2.04[5] |
| Details | |
| Mass | 1.820±0.026[6] M☉ |
| Radius | 1.783±0.040[6] R☉ |
| Luminosity | 12.134±0.296[6] L☉ |
| Surface gravity (log g) | 4.346[7] cgs |
| Temperature | 7,928±88[7] K |
| Metallicity [Fe/H] | +0.38[7] dex |
| Rotational velocity (v sin i) | 33.1[7] km/s |
| Age | 500±200[6] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Epsilon Serpentis, Latinized from ε Serpentis, is a single,[9] white-hued star in the constellation Serpens, in its head (Serpens Caput). It is visible to the naked eye with an apparent visual magnitude of +3.69.[2] Based upon an annual parallax shift of 46.30 mas as seen from Earth,[1] it is located 70 light years from the Sun. It is moving closer to the Sun with a radial velocity of −9 km/s.[4]
This is an Am star [10] on the main-sequence with a stellar classification of kA2hA5mA7 V.[3] This notation indicates the spectrum displays the calcium K-line of an A2 star, the hydrogen lines of an A5 star, and the metal lines of an A7 star.[11] It has been examined for the presence of a magnetic field, but the detected level was not statistically significant.[12]
Epsilon Serpentis has an estimated 1.82 times the mass of the Sun and 1.78 times the Sun's radius.[6] The star is radiating 12[6] times the Sun's luminosity from its photosphere at an effective temperature of around 7,928 K.[7] It is a candidate for an infrared excess at a wavelength of 25 μm, suggesting a circumstellar disk of dust with a temperature of 250±70 K may be orbiting roughly 4.2 AU from the host star.[13] The star is around half[6] a billion years old and is spinning with a projected rotational velocity of 33.1 km/s.[7]
Etymology
[edit ]Epsilon Serpentis was a member of indigenous Arabic asterism al-Nasaq al-Yamānī, "the Southern Line" of al-Nasaqān "the Two Lines".[14] along with α Ser (Unukalhai), δ Ser, δ Oph (Yed Prior), ε Oph (Yed Posterior), ζ Oph and γ Oph.[15]
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).[16]
In Chinese, 天市右垣 (Tiān Shì Yòu Yuán), meaning Right Wall of Heavenly Market Enclosure , refers to an asterism which represents eleven old states in China and which marks the right borderline of the enclosure, consisting of ε Serpentis, β Herculis, γ Herculis, κ Herculis, γ Serpentis, β Serpentis, α Serpentis, δ Serpentis, δ Ophiuchi, ε Ophiuchi and ζ Ophiuchi.[17] Consequently, the Chinese name for ε Serpentis itself is 天市右垣八 (Tiān Shì Yòu Yuán bā, English: the Eighth Star of Right Wall of Heavenly Market Enclosure), represent the state Ba (巴) (or Pa).[18] [19] [20]
References
[edit ]- ^ a b c d e f van Leeuwen, F. (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 Feinstein, A. (1974), "Photoelectric UBVRI observations of Am stars", Astronomical Journal, 79: 1290, Bibcode:1974AJ.....79.1290F, doi:10.1086/111675.
- ^ a b Gray, R. O.; et al. (July 2006), "Contributions to the Nearby Stars (NStars) Project: spectroscopy of stars earlier than M0 within 40 pc-The Southern Sample", The Astronomical Journal , 132 (1): 161–170, arXiv:astro-ph/0603770 , Bibcode:2006AJ....132..161G, doi:10.1086/504637, S2CID 119476992.
- ^ a b de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, arXiv:1208.3048 , Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, S2CID 59451347, A61.
- ^ 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.
- ^ a b c d e f g Boyajian, Tabetha S.; et al. (February 2012), "Stellar Diameters and Temperatures. I. Main-sequence A, F, and G Stars", The Astrophysical Journal, 746 (1): 101, arXiv:1112.3316 , Bibcode:2012ApJ...746..101B, doi:10.1088/0004-637X/746/1/101, S2CID 18993744.. See Table 10.
- ^ a b c d e f 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.
- ^ "eps Ser". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2017年09月26日.
{{cite web}}: CS1 maint: postscript (link) - ^ Rodriguez, David R.; et al. (May 2015), "Stellar multiplicity and debris discs: an unbiased sample", Monthly Notices of the Royal Astronomical Society, 449 (3): 3160–3170, arXiv:1503.01320 , Bibcode:2015MNRAS.449.3160R, doi:10.1093/mnras/stv483 , S2CID 119237891.
- ^ Adelman, Saul J.; Albayrak, Berahitdin (October 1998), "Elemental abundance analyses with DAO spectrograms - XX", Monthly Notices of the Royal Astronomical Society, 300 (2): 359–372, Bibcode:1998MNRAS.300..359A, doi:10.1046/j.1365-8711.1998.01859.x
- ^ Walker, Richard (2017), Spectral Atlas for Amateur Astronomers: A Guide to the Spectra of Astronomical Objects and Terrestrial Light Sources, Cambridge University Press, p. 116, ISBN 978-1316738764.
- ^ Shorlin, S. L. S.; et al. (September 2002), "A highly sensitive search for magnetic fields in B, A and F stars", Astronomy and Astrophysics, 392 (2): 637–652, Bibcode:2002A&A...392..637S, doi:10.1051/0004-6361:20021192 .
- ^ Smith, R.; Wyatt, M. C. (June 2010), "Warm dusty discs: exploring the A star 24 μm debris population", Astronomy and Astrophysics, 515: 16, arXiv:1004.0644 , Bibcode:2010A&A...515A..95S, doi:10.1051/0004-6361/200913481, S2CID 118989677, A95.
- ^ 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.
{{citation}}: CS1 maint: multiple names: authors list (link) - ^ 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年12月12日.
- ^ Rhoads, Jack W. (November 15, 1971), Technical Memorandum 33-507-A Reduced Star Catalog Containing 537 Named Stars (PDF), Jet Propulsion Laboratory, California Institute of Technology.
{{citation}}: CS1 maint: location missing publisher (link) - ^ (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.
- ^ Allen, Richard Hinckley (1963), "Serpens", Star Names, p. 376
- ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 24 日 Archived 2019年04月04日 at the Wayback Machine
- ^ (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.