请输入您要查询的百科知识：

　

词条 Alpha Herculis
释义

  1. Nomenclature

  2. Properties

  3. See also

  4. References

  5. External links

{{Starbox begin
| name = α Herculis
}}{{Starbox image
| image={{Location mark
|image=Hercules constellation map.svg|alt=|float=center|width=240
|label=|position=right
|mark=Red circle.svg|mark_width=10|mark_link=α Herculis
|x=596|y=896
}}
|caption=Location of α Herculis (circled)
}}{{Starbox observe 2s
| epoch = J2000
| constell = Hercules
| component1 = A
| ra1 = {{RA|17|14|38.853}}[1]
| dec1 = {{DEC|+14|23|25.0}}[1]
| appmag_v1 = 3.350[1] ({{Val|2.7|-|4.0}}[4])
| component2 = B
| ra2 = {{RA|17|14|39.181}}[1]
| dec2 = {{DEC|+14|23|23.98}}[1]
| appmag_v2 = 5.322[1]
}}{{Starbox character
| component = A
| type = AGB[8]
| class = M5 Ib-II[2]
| b-v = +1.45[3]
| u-b = +1.01[3]
| variable = SRc[4]
| component2 = B
| class2 = G8III + A9IV-V[2]
| b-v2 =
| u-b2 =
| variable2 =
}}{{Starbox astrometry
| prop_mo_ra = −6.71[14][15][16]
| prop_mo_dec = 32.78[14][15][16]
| parallax = 9.07
| p_error = 1.32
| parallax_footnote = [14][15]
| absmag_v = −2.3[5] + {{nowrap|1.8 + 2.8[6]}}
}}{{Starbox detail
| source = [2]
| component1 = A
| mass = {{Val|2.175|-|3.250}}
| radius = 284 ± 60, {{nowrap|{{Val|264|-|303}}}}
| luminosity = {{Val|7244|-|9333|fmt=commas}}
| temperature = {{Val|3155|-|3365|fmt=commas}}
| metal =
| gravity = {{Val|−0.41|0.19}}[25]
| rotational_velocity =
}}{{Starbox detail|no_heading=y
| component1 = Ba
| mass = ~2.5
| radius =
| luminosity = 126
| temperature = 4,900
| component2 = Bb
| mass2 = ~2
| radius2 =
| luminosity2 = 26
| temperature2 = 7,350
| age_gyr2 = {{Val|0.41|-|1.25}}
}}{{Starbox catalog
|names=Ras Algethi, Rasalgethi, α Her, 64 Her, BD+14°3207, HIP 84345, CCDM J17146+1424, AAVSO 1710+14, WDS J17146+1423
|component1=A
|names1=HD 156014, HR 6406, SAO 102680
|component2=B
|names2=HD 156015, HR 6407, SAO 102681
}}{{Starbox reference
| Simbad=HIP+84345|sn=α Her
| Simbad2=HD+156014|sn2=A
| Simbad3=HD+156015|sn3=B
}}{{Starbox end}}Alpha Herculis (α Herculis, abbreviated Alpha Her, α Her), also designated 64 Herculis, is a multiple star system in the constellation of Hercules. Appearing as a single point of light to the naked eye, it is resolvable into a number of components through a telescope. It has a combined apparent magnitude of 3.08, although the brightest component is variable in brightness.[26] Based on parallax measurements obtained during the Hipparcos mission, it is approximately 360 light-years (110 parsecs) distant from the Sun.[14][15]

It consists of two binary pairs in mutual orbit designated α¹ Herculis or α Herculis A (the brightest of the two) and α² Herculis or α Herculis B.[7][8] A's two components are themselves designated α Herculis Aa (also named Rasalgethi[9]) and Ab; B's as α Herculis Ba and Bb.

Alpha Herculis also forms the A and B components of a wider system designated WDS J17146+1423 with two additional visual companions designated WDS J17146+1423C and D.[10]

Nomenclature

α Herculis (Latinised to Alpha Herculis) is the system's Bayer designation; α¹ and α² Herculis, those of its two components. 64 Herculis is the system's Flamsteed designation. WDS J17146+1423 is the wider system's designation in the Washington Double Star Catalog. The designations of Alpha Herculis' two components as Alpha Herculis A and B and the wider system's four components as WDS J17146+1423A, B, C and D, together with those of A's and B's components - Alpha Herculis Aa, Ab, Ba and Bb - derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU).[11]

Alpha Herculis bore the traditional name Rasalgethi or Ras Algethi ({{lang-ar|رأس الجاثي ra‘is al-jāthī}} 'Head of the Kneeler').[12] 'Head' comes from the fact that in antiquity Hercules was depicted upside down on maps of the constellation. In 2016, the IAU organized a Working Group on Star Names (WGSN)[13] to catalog and standardize proper names for stars. The WGSN approved the name Rasalgethi for the component Alpha Herculis Aa on 30 June 2016 and it is now so included in the List of IAU-approved Star Names.[9]

The term ra's al-jaθiyy or Ras al Djathi appeared in the catalogue of stars in the Calendarium of Al Achsasi al Mouakket, which was translated into Latin as Caput Ingeniculi.[14]

In Chinese astronomy, Alpha Herculis is called 帝座, Pinyin: Dìzuò, meaning 'Emperor's Seat', this star is marking itself and stands alone in the center of the Emperor's Seat asterism, Heavenly Market enclosure (see : Chinese constellations).[15] 帝座 (Dìzuò) was westernized into Ti Tso by R.H. Allen, with the same meaning [16]

Properties

Alpha Herculis A and B are more than 500 AU apart, with an estimated orbital period of approximately 3600 years. A presents as a relatively massive red bright giant, but radial velocity measurements suggest a companion with a period of the order of a decade.[10] B's two components are a primary yellow giant star and a secondary, yellow-white dwarf star in a 51.578 day orbit.

Alpha Herculis Aa is an asymptotic giant branch (AGB) star, a luminous red giant that has both hydrogen and helium shells around a degenerate carbon-oxygen core. It is the second nearest AGB star to the Sun.[2] The angular diameter of the star has been measured with an interferometer as

34 ± 0.8 mas, or 0.034 arcseconds.[17] At its estimated distance of 110 parsecs this corresponds to a radius of about 280 million kilometers (or 170 million miles), which is roughly {{Solar radius|link=y|400}} or 1.87 AU.[18] If Rasalgethi were at the center of the Solar System its radius would extend past the orbit of Mars at 1.5 AU but not quite as far as the asteroid belt. The red giant is estimated to have started its life with about {{solar mass|2.175-3.250}}.[2]

Like most type M stars near the end of their lives, Rasalgethi is experiencing a high degree of stellar mass loss creating a sparse, gaseous envelope that extends at least 90 AU.[45] It is a semiregular variable with complex changes in brightness with periods ranging from a few weeks to many years. The most noticeable variations occur at timescales of 80–140 days and at 1,000 - 3,000 days. The strongest detectable period is 128 days. The full range in brightness is from magnitude 2.7 to 4.0,[4] but it usually varies over a much smaller range of around 0.6 magnitudes.

See also

  • List of largest known stars
  • Lists of stars in the constellation Hercules
  • Betelgeuse mass loss
  • Spectral types F, G & M

References

1. ^1 2 3 4 5 {{cite journal|bibcode=2000A&A...355L..27H|title=The Tycho-2 catalogue of the 2.5 million brightest stars|journal=Astronomy and Astrophysics|volume=355|pages=L27|author1=Høg|first1=E.|last2=Fabricius|first2=C.|last3=Makarov|first3=V. V.|last4=Urban|first4=S.|last5=Corbin|first5=T.|last6=Wycoff|first6=G.|last7=Bastian|first7=U.|last8=Schwekendiek|first8=P.|last9=Wicenec|first9=A.|year=2000|doi=10.1888/0333750888/2862|isbn=0333750888}}
2. ^1 2 3 4 5 {{cite journal|bibcode=2013AJ....146..148M|arxiv=1308.1632|title=The Age and Mass of the α Herculis Triple-star System from a MESA Grid of Rotating Stars with 1.3 <= M/M ⊙ <= 8.0|journal=The Astronomical Journal|volume=146|issue=6|pages=148|author1=Moravveji|first1=Ehsan|last2=Guinan|first2=Edward F.|last3=Khosroshahi|first3=Habib|last4=Wasatonic|first4=Rick|year=2013|doi=10.1088/0004-6256/146/6/148}}
3. ^1 {{cite journal|bibcode=2002yCat.2237....0D|title=VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system|journal=CDS/ADC Collection of Electronic Catalogues|volume=2237|author1=Ducati|first1=J. R.|year=2002}}
4. ^1 2 {{cite journal|bibcode=2009yCat....102025S|title=VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)|journal=VizieR On-line Data Catalog: B/gcvs. Originally published in: 2009yCat....102025S|volume=1|display-authors=etal|author1=Samus|first1=N. N.|last2=Durlevich|first2=O. V.|year=2009}}
5. ^{{cite journal|bibcode=2012A&A...547A..62H|arxiv=1210.7893|title=A catalogue of Paschen-line profiles in standard stars|journal=Astronomy & Astrophysics|volume=547|pages=A62|author1=Huang|first1=W.|last2=Wallerstein|first2=G.|last3=Stone|first3=M.|year=2012|doi=10.1051/0004-6361/201219804}}
6. ^{{cite journal|bibcode=1977A&A....61..217R |title=On the absolute scale of mass-loss in red giants. I - Circumstellar absorption lines in the spectrum of the visual companion of Alpha-1 HER |journal=Astronomy and Astrophysics |volume=61 |pages=217 |author1=Reimers |first1=D. |year=1977 }}
7. ^{{cite journal|bibcode= 1997A&AS..124...75T|title= MSC - a catalogue of physical multiple stars|journal= Astronomy & Astrophysics Supplement Series|volume= 124|pages= 75|author1= Tokovinin|first1= A. A.|year= 1997|doi= 10.1051/aas:1997181}}
8. ^{{cite web | url=http://www.ctio.noao.edu/~atokovin/stars/stars.php?cat=HIP&number=84345 | title=Displaying next number in catalog HIP => 84345 | work=Multiple Star Catalog | accessdate=2018-07-10}}
9. ^1 {{cite web | url=https://www.iau.org/public/themes/naming_stars/ | title=Naming Stars |publisher=IAU.org |accessdate=18 June 2018}}
10. ^1 {{cite web | url=http://ad.usno.navy.mil/wds/ | title=Washington Double Star Catalog | publisher=United States Naval Observatory | accessdate=2018-07-10 | archive-url=https://web.archive.org/web/20110214155533/http://ad.usno.navy.mil/wds/ | archive-date=2011-02-14 | dead-url=yes | df= }}
11. ^{{cite arXiv |title=On the naming convention used for multiple star systems and extrasolar planets |date=2010 |eprint=1012.0707 |class=astro-ph.SR |last1= Hessman |first1=F. V. |last2= Dhillon |first2=V. S. |last3= Winget |first3=D. E. |last4= Schreiber |first4=M. R. |last5= Horne |first5=K. |last6= Marsh |first6=T. R. |last7= Guenther |first7=E. |last8= Schwope |first8=A. |last9= Heber |first9=U. }}
12. ^{{cite web |title=Constellations: Hercules 'the Strongman' |publisher=The BBC (British Broadcasting Corporation) |author=Kurt Vonnegut |url=http://www.bbc.co.uk/dna/h2g2/A29778916 |accessdate=2010-11-14}}
13. ^{{cite web | url=https://www.iau.org/science/scientific_bodies/working_groups/280/ | title=IAU Working Group on Star Names (WGSN)|accessdate=22 May 2016}}
14. ^{{cite journal | last=Knobel | first=E. B. | title=Al Achsasi Al Mouakket, on a catalogue of stars in the Calendarium of Mohammad Al Achsasi Al Mouakket | journal=Monthly Notices of the Royal Astronomical Society | volume=55 | issue=8 | page=429 |date=June 1895 | bibcode=1895MNRAS..55..429K | doi=10.1093/mnras/55.8.429}}
15. ^{{zh icon}} AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 25 日
16. ^Richard Hinckley Allen: Star Names — Their Lore and Meaning: Hercules
17. ^{{cite journal | display-authors=5 | author=Benson, J. A. | author2=Dyck, H. M. | author3=Mason, W. L. | author4=Howell, R. R. | author5=Ridgway, S. T. | author6=Dixon, D. J. | title=The infrared angular diameter of Alpha Herculis measured with a Michelson interferometer | journal=Astronomical Journal |date=December 1991 | volume=102 | pages=2091–2097 | doi= 10.1086/116033 | bibcode=1991AJ....102.2091B }}
18. ^To determine Rasalgethi's radius in terms of solar units, the calculations begin with the formula for angular diameter as follows::where δ equals Rasalgethi's angular diameter in arcseconds, dR the star's diameter in AU, and DR the Distance from Earth in parsecs. If one knows the angular diameter and the Distance, then one can solve for dR as follows::.To obtain Rasalgheti's radius::.Converting into Solar units, 1 AU = 149,597,871 km and the mean radius of the Sun = 696,000 km, hence the calculation:: (rounded).
19. ^1 {{cite journal | last=Deutsch | first=Armin J. | title=The Circumstellar Envelope of Alpha Herculis | journal=Astrophysical Journal |date=March 1956 | volume=123 | pages=210–227 | doi=10.1086/146152 | bibcode=1956ApJ...123..210D}}
20. ^1 {{citation | last1=Schröder | first1=K.-P. | last2=Cuntz | first2=M. | title=A critical test of empirical mass loss formulas applied to individual giants and supergiants | journal=Astronomy and Astrophysics | volume=465 | issue=2 | pages=593–601 |date=April 2007 | doi=10.1051/0004-6361:20066633 | bibcode=2007A&A...465..593S |arxiv = astro-ph/0702172 }}
21. ^1 2 {{cite simbad | title = alf Her | access-date = 2010-09-26 }}
22. ^1 2 3 4 {{citation | last1=Perryman | first1=M. A. C. | last2=Lindegren | first2=L. | last3=Kovalevsky | first3=J. | title=The Hipparcos Catalogue | journal=Astronomy and Astrophysics | volume=323 |date=July 1997 | pages=L49–L52 | bibcode=1997A&A...323L..49P|display-authors=etal}}
23. ^1 2 3 4 {{cite journal | title=Hipparcos, the New Reduction | last1=van Leeuwen | first1=F |date=November 2007 | publisher=Centre de Données astronomiques de Strasbourg | pages=653 | issue=2 | volume=474 | doi=10.1051/0004-6361:20078357 | journal=Astronomy and Astrophysics | bibcode=2007A&A...474..653V |arxiv = 0708.1752 }}
24. ^1 {{cite journal |bibcode=1991bsc..book.....H |title=The Bright star catalogue |journal=New Haven |author1=Hoffleit |first1=Dorrit |last2=Jaschek |first2=Carlos |year=1991}}
25. ^{{citation | last=Perryman | first=Michael | title=The Making of History's Greatest Star Map | location=Heidelberg | publisher=Springer-Verlag | date=2010 | doi=10.1007/978-3-642-11602-5| series=Astronomers’ Universe | isbn=978-3-642-11601-8 | bibcode=2010mhgs.book.....P}}
[19][20][21][22][23][24]
}}

External links

  • An Atlas of the Universe: Multiple Star Orbits
  • Upside down Hercules showing Rasalgethi as the head: Hercules
{{Sky|17|14|38.858|+|14|23|25.20|1000000}}{{Stars of Hercules}}

16 : Double stars|Hercules (constellation)|Bayer objects|Flamsteed objects|Triple star systems|Stars with proper names|M-type bright giants|G-type giants|F-type main-sequence stars|HR objects|Hipparcos objects|Henry Draper Catalogue objects|Durchmusterung objects|Semiregular variable stars|M-type supergiants|Asymptotic-giant-branch stars
随便看

　

开放百科全书收录14589846条英语、德语、日语等多语种百科知识，基本涵盖了大多数领域的百科知识，是一部内容自由、开放的电子版国际百科全书。

　

Copyright © 2023 OENC.NET All Rights Reserved
京ICP备2021023879号 更新时间：2024/11/10 11:58:32