الشرطان (نجم)


β Arietis
Aries constellation map.svg
Red circle.svg
Location of β Arietis (circled)
بيانات الرصـد
الحقبة J2000      اعتدال J2000
الكوكبة Aries
الصعود المستقيم 01h 54m 38.41099s[1]
الميل +20° 48′ 28.9133″[1]
القدر الظاهري (V)2.655[2] (2.712 + 5.789[3])
الخـصـائص
النوع الطيفيA3V + G2V[3]
U-B دليل الألوان+0.170[2]
B-V دليل الألوان+0.142[2]
علم القياسات الفلكية
السرعة القطرية (Rv)-1.9[4] كم/ث
الحركة الحقيقية (μ) RA: +98.74[1] mas/yr
Dec.: -110.41[1] mas/س
اختلاف المنظر (π)55.827 ± 0.308[3] mas
المسافةس ض
( ف ن)
القدر المطلق (MV)1.382 (1.444 + 4.521)[3]
المدار[5]
CompanionBeta Arietis B
Period (P)106.9954 ± 0.0005 days
Semimajor axis (a)36.1 ± 0.3 mas
Eccentricity (e)0.903 ± 0.012
Inclination (i)44.7 ± 1.3°
Longitude of the node (Ω)79.1 ± 0.8°
Argument of periastron (ω)
(secondary)		209.1 ± 1.2°
التـفـاصـيل[3]
A
الكتلة2.067±0.057 M☉
نصف القطر1٫985 ± 0٫229[أ] R☉
جاذبية السطح (log g)4.0[6]
الضياء20.9+5.4
−4.3 L☉
درجة الحرارة8,759 ك
سرعة الدوران (v sin i)73[7] كم/ث
B
الكتلة1.058±0.026 M☉
نصف القطر1٫12 ± 0٫064[أ] R☉
الضياء1.29+0.16
−0.14 L☉
Temperature5,811 ك
تسميات أخرى
Sheratan, Sharatan, Al Sharatain,[8] 6 Arietis, Gl 80, HR 553, BD +20°306, HD 11636, SAO 75012, FK5 66, HIP 8903.[9]
مراجع قواعد البيانات
SIMBADdata
ARICNSdata

الشرطان أو بيتا الحمل Beta Arietis اسمه التقليدي Sheratan مشتق من الاسم العربي و هو نجم ثنائي في كوكبة الحمل .

يملك الشرطان قدر ظاهري 2.26+ و ينتمي إلى الفئة الطيفية A5V و هو نجم أبيض في مرحلة النسق الأساسي ويبعد 59.6 سنة ضوئية عن الأرض. يدور رفيقه حوله في فترة مدارية قدرها 107 يوم مع شذوذ مداري كبير وغريب 0.88 و يحتمل أن ينتمي رفيقه إلى الفئة الطيفية G

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Nomenclature

Beta Arietis is the star's Bayer designation. It also bears the Flamsteed designation 6 Arietis.

The traditional name, Sheratan (or Sharatan, Sheratim),[8] in full Al Sharatan, is from the Arabic الشرطان aš-šaraţān "the two signs", a reference to the star having marked the northern vernal equinox together with Gamma Arietis several thousand years ago.[بحاجة لمصدر] In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[10] to catalogue and standardize proper names for stars. The WGSN approved the name Sheratan for this star on 21 August 2016 and it is now so entered in the IAU Catalog of Star Names.[11]

In Chinese, 婁宿 (Lóu Xiù), meaning Bond (asterism), refers to an asterism consisting of β Arietis, γ Arietis and α Arietis.[12] Consequently, the Chinese name for β Arietis itself is 婁宿一 (Lóu Su yī, إنگليزية: the First Star of Bond).[13]


Properties

Beta Arietis has an apparent visual magnitude of 2.65. Based on dynamical parallax measurements, it is located at a distance of 58.4 light-years (17.9 parsecs) from Earth.[3] This is a spectroscopic binary star system consisting of a pair of stars orbiting around each other with a separation that can not currently be resolved with a conventional telescope. However, the pair have been resolved using the Mark III Stellar Interferometer at the Mount Wilson Observatory. This allows the orbital elements to be computed, as well as the individual masses of the two stars. The stars complete their highly elliptical orbit every 107 days.[5]

The primary star has a stellar classification of A3 V,[3] which means it is an A-type main-sequence star that is generating energy through the thermonuclear fusion of hydrogen in its core region. The NStars project gives the star a spectral type of kA4 hA5 mA5 Va under the revised MK spectral classification system.[14] The secondary star is a G-type main-sequence star, with a stellar classification of G2V.[3] It is about four magnitudes fainter than the primary; hence the energy output from the system is dominated by the primary star.[5] In a few million years, as the primary evolves toward a red giant, significant amounts of mass transfer to the secondary component is expected.[15]

The primary has been classified as a rapid rotator, with a projected rotational velocity of 73 km/s providing a lower bound on the azimuthal rotational velocity along the equator.[7] It may also be a mildly Am star, which is a class of stars that show a peculiar spectrum with strong absorption lines from various elements and deficiencies in others. In β Arietis, these absorption lines are broadened because of the Doppler effect from the rotation, making analysis of the abundance patterns difficult.[6]

This system has been examined with the Spitzer Space Telescope for the presence of an excess emission of infrared, which would indicate a disk of dust. However, no significant excess was detected.[14]

الهامش

  1. ^ أ ب Calculated, using the Stefan-Boltzmann law and the star's effective temperature and luminosity, with respect to the solar nominal effective temperature of 5,772 K:

انظر أيضا

المراجع

  1. ^ أ ب ت ث van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode: 2007A&A...474..653V 
  2. ^ أ ب ت Gutierrez-Moreno, Adelina; et al. (1966). "A System of photometric standards". Publications of the Department of Astronomy University of Chile. Publicaciones Universidad de Chile, Department de Astronomy. 1: 1–17. Bibcode:1966PDAUC...1....1G.
  3. ^ أ ب ت ث ج ح خ د Piccotti, Luca; Docobo, José Ángel; Carini, Roberta; Tamazian, Vakhtang S.; Brocato, Enzo; Andrade, Manuel; Campo, Pedro P. (2020-02-01). "A study of the physical properties of SB2s with both the visual and spectroscopic orbits". Monthly Notices of the Royal Astronomical Society. 492 (2): 2709–2721. Bibcode:2020MNRAS.492.2709P. doi:10.1093/mnras/stz3616. ISSN 0035-8711.
  4. ^ 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.
  5. ^ أ ب ت Pan, X. P.; Shao, M.; Colavita, M. M.; Mozurkewich, D.; Simon, R. S.; Johnston, K. J. (1990), "Apparent orbit of the spectroscopic binary Beta Arietis with the time Mark III Stellar Interferometer", Astrophysical Journal 356: 641–645, doi:10.1086/168870, Bibcode: 1990ApJ...356..641P 
  6. ^ أ ب Mitton, J. (January 1977), "Spectroscopic observations and curve-of-growth analyses of the four A stars omicron Peg, beta Ari, kappa Ari and 32 Vir.", Astronomy and Astrophysics Supplement Series 27: 35–46, Bibcode: 1977A&AS...27...35M 
  7. ^ أ ب Royer, F.; Zorec, J.; Gómez, A. E. (February 2007), "Rotational velocities of A-type stars. III. Velocity distributions", Astronomy and Astrophysics 463 (2): 671–682, doi:10.1051/0004-6361:20065224, Bibcode: 2007A&A...463..671R 
  8. ^ أ ب Allen, Richard Hinckley (1899), Star-Names and Their Meanings, New York: G. E. Stechert, pp. 81–82, https://books.google.com/books?id=5xQuAAAAIAAJ&pg=PA81, retrieved on 2011-12-24 
  9. ^ bet Ari -- Spectroscopic binary, Centre de Données astronomiques de Strasbourg, http://simbad.u-strasbg.fr/simbad/sim-id?Ident=Beta+Arietis, retrieved on 2011-12-29 
  10. ^ IAU Working Group on Star Names (WGSN), International Astronomical Union, https://www.iau.org/science/scientific_bodies/working_groups/280/, retrieved on 22 May 2016. 
  11. ^ خطأ استشهاد: وسم <ref> غير صحيح؛ لا نص تم توفيره للمراجع المسماة IAU-CSN
  12. ^ (in صينية) 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. ^ (in صينية) 香港太空館 - 研究資源 - 亮星中英對照表 Archived 2010-08-18 at the Wayback Machine, Hong Kong Space Museum. Accessed on line November 23, 2010.
  14. ^ أ ب Gray, R. O.; Corbally, C. J.; Garrison, R. F.; McFadden, M. T.; Robinson, P. E. (October 2003), "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 Parsecs: The Northern Sample. I.", The Astronomical Journal 126 (4): 2048–2059, doi:10.1086/378365, Bibcode: 2003AJ....126.2048G 
  15. ^ Fuhrmann, Klaus (February 2008), "Nearby stars of the Galactic disc and halo - IV", Monthly Notices of the Royal Astronomical Society 384 (1): 173–224, doi:10.1111/j.1365-2966.2007.12671.x, Bibcode: 2008MNRAS.384..173F 

External links

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