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Mu Herculis: Difference between revisions

Coordinates: Sky map 17h 46m 27.52667s, +27° 43′ 14.4379″
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{{Short description|Quadruple star system in the constellation Hercules}}
{{Sky|17|46|27.52667|+|27|43|14.4379|27.1}}
{{Starbox begin
{{Starbox begin
| name=Mu Herculis Aa/B/C/D }}
| name=Mu Herculis }}
{{Starbox observe
{{Starbox image
| image = [[File:Hercules Historical View.png|250px]]
| caption =Historical view of the [[Hercules (constellation)|Hercules]] constellation showing Mu Herculis (μ Her) as one of stars in the hero's elbow.}}
{{Starbox observe 2s
| epoch=J2000
| epoch=J2000
| ra=17<sup>h</sup> 46<sup>m</sup> 27.5<sup>s</sup>
| component1=μ Her Aab (μ<sup>1</sup> Her)
| constell=[[Hercules (constellation)|Hercules]]
| dec=+27&deg; 43&prime; 14&Prime;
| ra1={{RA|17|46|27.52667}}<ref name=aaa474_2_653/>
| appmag_v=3.42/10.35/10.80/12.00
| dec1={{DEC|+27|43|14.4379}}<ref name=aaa474_2_653/>
| constell=[[Hercules (constellation)|Hercules]] }}
| appmag_v1={{nowrap|3.417 ± 0.014}}<ref name=aaa474_2_653/>
| component2=μ Her BC (μ<sup>2</sup> Her)
| ra2={{RA|17|46|25.079}}<ref name=2MASS>{{cite journal|title=2MASS All-Sky Catalog of Point Sources|date=2003|journal=VizieR On-line Data Catalog|author=Cutri, R. M.|volume = 2246|display-authors=etal|bibcode=2003yCat.2246....0C}}</ref>
| dec2={{DEC|+27|43|01.45}}<ref name=2MASS/>
| appmag_v2=10.2 / 10.7<ref name=ORB6>{{cite web|url=http://www.usno.navy.mil/USNO/astrometry/optical-IR-prod/wds/orb6|title=Sixth Catalog of Orbits of Visual Binary Stars|work=United States Naval Observatory|access-date=23 March 2017|archive-date=1 August 2017|archive-url=https://web.archive.org/web/20170801102553/http://www.usno.navy.mil/USNO/astrometry/optical-IR-prod/wds/orb6}}</ref>
}}
{{Starbox character
{{Starbox character
| component=μ Her Aab
| class=G5 IV/M3.5 V/M4 V
| class=G5IV<ref name=na15_4_367/> / M4V<ref name=Roberts/>
| b-v=0.75/1.50
| b-v=+0.76<ref name=EgUBV>{{cite journal|author1=Mermilliod, J.-C.|title=Compilation of Eggen's UBV data, transformed to UBV (unpublished)|journal=Catalogue of Eggen's UBV Data|page=0|url=http://cdsads.u-strasbg.fr/cgi-bin/nph-bib_query?1986EgUBV........0M&db_key=AST&nosetcookie=1|date=1986|bibcode= 1986EgUBV........0M}}</ref>
| u-b=0.39/1.01
| u-b=+0.40<ref name=EgUBV/>
| variable=Periodic }}
| variable=
}}
{{Starbox character|no_heading=y
| component=μ Her BC
| class=M3.5V<ref name=CARMENES>{{cite journal |doi=10.1051/0004-6361/201525803 |title=CARMENES input catalogue of M dwarfs |journal=Astronomy & Astrophysics |volume=577 |pages=A128 |year=2015 |last1=Alonso-Floriano |first1=F. J. |last2=Morales |first2=J. C. |last3=Caballero |first3=J. A. |last4=Montes |first4=D. |last5=Klutsch |first5=A. |last6=Mundt |first6=R. |last7=Cortés-Contreras |first7=M. |last8=Ribas |first8=I. |last9=Reiners |first9=Ansgar |last10=Amado |first10=P. J. |last11=Quirrenbach |first11=A. |last12=Jeffers |first12=S. V. |arxiv=1502.07580 |bibcode=2015A&A...577A.128A |s2cid=53135130 |url=http://goedoc.uni-goettingen.de/goescholar/bitstream/handle/1/12402/aa25803-15.pdf }}{{Dead link|date=September 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>
| b-v=+1.50<ref name=EgUBV/>
| u-b=+1.00<ref name=EgUBV/>
}}
{{Starbox astrometry
{{Starbox astrometry
| component1=μ Her Aab
| radial_v=-16.1/-13.7
| radial_v=−17.07 ± 0.12<ref name=Grundahl/>
| prop_mo_ra=-291.42/-77.62
| prop_mo_ra=−291.66<ref name=aaa474_2_653/>
| prop_mo_dec=-750.00/-270.12
| prop_mo_dec=−749.60<ref name=aaa474_2_653/>
| parallax=119.02
| p_error=0.58
| parallax=120.33
| dist_ly=27.39
| p_error=0.16
| parallax_footnote=<ref name=aaa474_2_653/>
| dist_pc=8.40
| absmag_v=3.80/10.73/11.18/12.38 }}
| absmag_v=3.82 ± 0.02<ref name=Grundahl/>
| component2=μ Her BC
| prop_mo_ra2=−343.35<ref name=Roeser>{{cite journal|bibcode=2008A&A...488..401R|doi=10.1051/0004-6361:200809775|arxiv=0806.1009|title=PPM-Extended (PPMX) – a catalogue of positions and proper motions|journal=Astronomy and Astrophysics|volume=488|issue=1|page=401|year=2008|last1=Röser|first1=S.|last2=Schilbach|first2=E.|last3=Schwan|first3=H.|last4=Kharchenko|first4=N. V.|last5=Piskunov|first5=A. E.|last6=Scholz|first6=R.-D.|s2cid=17350617}}</ref>
| prop_mo_dec2=−743.88<ref name=Roeser/>
| parallax2 = 119.8871
| p_error2 = 0.2055
| parallax_footnote2 = <ref name=dr2bc>{{cite Gaia EDR3|4594497834189213184}}</ref>
| absmag_v2=+10.26<ref name=davison>{{cite journal|bibcode=2015AJ....149..106D|title=A 3D Search for Companions to 12 Nearby M Dwarfs|journal=The Astronomical Journal|volume=149|issue=3|page=106|last1=Davison|first1=Cassy L.|last2=White|first2=R. J.|last3=Henry|first3=T. J.|last4=Riedel|first4=A. R.|last5=Jao|first5=W. -C.|last6=Bailey|first6=J. I.|last7=Quinn|first7=S. N.|last8=Cantrell|first8=J. R.|last9=Subasavage|first9=J. P.|last10=Winters|first10=J. G.|year=2015|doi=10.1088/0004-6256/149/3/106|arxiv=1501.05012|s2cid=9719725}}</ref>
}}
{{Starbox relpos
| reference = <ref name=Simbad2/>
| primary = μ Her Aab
| component = μ Her BC
| angdistsec = 35
}}
{{Starbox orbit
| reference=<ref name=Roberts>{{cite journal|bibcode=2016AJ....151..169R|doi=10.3847/0004-6256/151/6/169|arxiv=1604.06494|title=Characterization of the Companion to μ Her|journal=The Astronomical Journal|volume=151|issue=6|page=169|year=2016|last1=Roberts Jr.|first1=Lewis C.|last2=Mason|first2=Brian D.|last3=Aguilar|first3=Jonathan|last4=Carson|first4=Joseph|last5=Crepp|first5=Justin|last6=Beichman|first6=Charles|last7=Brenner|first7=Douglas|last8=Burruss|first8=Rick|last9=Cady|first9=Eric|last10=Luszcz-Cook|first10=Statia|last11=Dekany|first11=Richard|last12=Hillenbrand|first12=Lynne|last13=Hinkley|first13=Sasha|last14=King|first14=David|last15=Lockhart|first15=Thomas G.|last16=Nilsson|first16=Ricky|last17=Oppenheimer|first17=Rebecca|last18=Parry|first18=Ian R.|last19=Pueyo|first19=Laurent|last20=Rice|first20=Emily L.|last21=Sivaramakrishnan|first21=Anand|last22=Soummer|first22=Rémi|last23=Vasisht|first23=Gautam|last24=Veicht|first24=Aaron|last25=Wang|first25=Ji|last26=Zhai|first26=Chengxing|last27=Zimmerman|first27=Neil T.|s2cid=43403927 |doi-access=free }}</ref>
| primary=μ Her Aa
| name=μ Her Ab
| period=98.9 ± 22.7
| axis=2.9 ± 0.3
| inclination=62.82 ± 4.66
| node=80.4 ± 1.7<!-- I can only assume they meant Omega instead of W -->
| periastron=[[Besselian year|B]] 1921.1 ± 23.8
| eccentricity=0.44 ± 0.06
| periarg=214 ± 16
| k1=1.12 ± 0.10
}}
{{Starbox orbit
| reference=<ref name=ORB6/>
| primary=μ Her B
| name=μ Her C
| period=43.127 ± 0.013
| axis=1.385 ± 0.038
| inclination=66.06 ± 0.15
| node=60.07 ± 0.17
| periastron=B 2008.335 ± 0.073
| eccentricity=0.1796 ± 0.0009
| periarg=172.85 ± 0.64
}}
{{Starbox detail
{{Starbox detail
| component1 = μ Her Aa
| mass=1.1/0.31/0.31
| temperature=5560 ± 80<ref name=Grundahl>{{cite journal|bibcode=2017ApJ...836..142G|doi=10.3847/1538-4357/836/1/142|arxiv=1701.03365|title=First Results from the Hertzsprung SONG Telescope: Asteroseismology of the G5 Subgiant Star μ Herculis|journal=The Astrophysical Journal|volume=836|issue=1|page=142|year=2017|last1=Grundahl|first1=F.|last2=Andersen|first2=M. Fredslund|last3=Christensen-Dalsgaard|first3=J.|last4=Antoci|first4=V.|last5=Kjeldsen|first5=H.|last6=Handberg|first6=R.|last7=Houdek|first7=G.|last8=Bedding|first8=T. R.|last9=Pallé|first9=P. L.|last10=Jessen-Hansen|first10=J.|last11=Aguirre|first11=V. Silva|last12=White|first12=T. R.|last13=Frandsen|first13=S.|last14=Albrecht|first14=S.|last15=Andersen|first15=M. I.|last16=Arentoft|first16=T.|last17=Brogaard|first17=K.|last18=Chaplin|first18=W. J.|last19=Harpsøe|first19=K.|last20=Jørgensen|first20=U. G.|last21=Karovicova|first21=I.|last22=Karoff|first22=C.|last23=Rasmussen|first23=P. Kjærgaard|last24=Lund|first24=M. N.|last25=Lundkvist|first25=M. Sloth|last26=Skottfelt|first26=J.|last27=Norup Sørensen|first27=A.|last28=Tronsgaard|first28=R.|last29=Weiss|first29=E.|s2cid=119480210 |doi-access=free }}</ref>
| radius=1.8/0.48/0.4
| gravity=3.98 ± 0.10<ref name=Grundahl/>
| luminosity=2.2-2.7/0.005/0.003
| metal_fe=0.28 ± 0.07<!-- from model --><ref name=Grundahl/>
| temperature=5,500
| rotational_velocity=1.7 ± 0.4<ref name=Grundahl/>
| metal=130-300%
| radius=1.73 ± 0.02<!-- angular diameter --><ref name=Grundahl/>
| rotation=20 km/sec.
| luminosity=2.54 ± 0.08<ref name=Grundahl/>
| age=? }}
| rotation={{val|52|+3|-1}} d<ref name=Grundahl/>
| age_gyr={{val|7.8|+0.3|-0.4}}<ref name=Grundahl/>
| mass=1.11 ± 0.01<ref name=Grundahl/>
| component2 = μ Her Ab
| mass2=0.32<ref name=Roberts/>
}}
{{Starbox detail|no_heading=y
| component1 = μ Her B
| mass=0.44<ref name=msc>{{cite web|url=http://www.ctio.noao.edu/~atokovin/stars/stars.php?cat=HR&number=6623|title=Multiple Star Catalog|access-date=2018-12-02|archive-date=2018-12-03|archive-url=https://web.archive.org/web/20181203010914/http://www.ctio.noao.edu/~atokovin/stars/stars.php?cat=HR&number=6623}}</ref>
| temperature = 4,050<ref name=gaidos>{{cite journal|bibcode=2014MNRAS.443.2561G|title=Trumpeting M dwarfs with CONCH-SHELL: A catalogue of nearby cool host-stars for habitable exoplanets and life|journal=Monthly Notices of the Royal Astronomical Society|volume=443|issue=3|page=2561|last1=Gaidos|first1=E.|last2=Mann|first2=A. W.|last3=Lépine|first3=S.|last4=Buccino|first4=A.|last5=James|first5=D.|last6=Ansdell|first6=M.|last7=Petrucci|first7=R.|last8=Mauas|first8=P.|last9=Hilton|first9=E. J.|year=2014|doi=10.1093/mnras/stu1313|arxiv=1406.7353|doi-access=free}}</ref>
| radius = 0.60<ref name=gaidos/>
| luminosity = 0.087<ref name=gaidos/>
| metal_fe = +0.21<ref name=gaidos/>
| component2 = μ Her C
| mass2=0.39<ref name=msc/>
}}
{{Starbox catalog
{{Starbox catalog
| names=86 Hercules, [[Henry L. Giclas catalogue|Gl]] 695 A/B/C, [[Harvard Revised catalogue|HR]] 6623 A/B/C, [[Bonner Durchmusterung|BD]] +27&deg;2888, [[Henry Draper catalogue|HD]] 161797, [[Luyten Half-Second catalogue|LHS]] 3326/3325, [[Luyten Two-Tenths catalogue|LTT]] 15266, [[General Catalogue of Trigonometric Parallaxes|GCTP]] 4060.00, [[Smithsonian Astrophysical Observatory|SAO]] 85397, FK5 667, LDS 1002, LFT 1374, GC 24138, ADS 10786, [[Hipparcos catalogue|HIP]] 86974. }}
| names=[[Flamsteed designation|86]] Herculis, [[Gliese Catalogue of Nearby Stars|Gl]] 695, [[Harvard Revised catalogue|HR]] 6623, [[Bonner Durchmusterung|BD]]+27°&nbsp;2888, [[Henry Draper catalogue|HD]] 161797, [[Luyten Half-Second catalogue|LHS]] 3326/3325, [[Luyten Two-Tenths catalogue|LTT]] 15266, [[Smithsonian Astrophysical Observatory Star Catalog|SAO]]&nbsp;85397, [[FK5]] 667, LFT 1374, [[Boss General Catalogue|GC]] 24138, [[Aitken Double Star Catalogue|ADS]] 10786, [[Hipparcos catalogue|HIP]] 86974.<ref name=Simbad1/>
}}
{{Starbox reference
|Simbad=mu+Her | sn=μ Her Aab
|Simbad2=mu.02+Her | sn2=μ Her BC
}}
{{Starbox end}}
{{Starbox end}}
'''Mu Herculis''' is a star system about 27.4 [[light year]]s from Earth in the [[constellation]][[Hercules (constellation)|Hercules]]. Its main star, Mu Herculis A (possibly a binary) is fairly similar to the [[Sun]] although more highly [[stellar evolution|evolved]]. Its mass is about 1.1 times that of the Sun, and it is beginning to expand to become a giant.
'''Mu Herculis''' ('''μ Herculis''') is a nearby quadruple [[star system]] about 27.1&nbsp;[[light year]]s from Earth in the [[constellation]] [[Hercules (constellation)|Hercules]]. Its main star, Mu Herculis A is fairly similar to the [[Sun]] although more highly [[stellar evolution|evolved]] with a [[stellar classification]] of G5&nbsp;IV. Since 1943, the [[stellar spectrum|spectrum]] of this star has served as one of the stable anchor points by which other stars are classified.<ref name=baas25_1319/> Its mass is about 1.1 times that of the Sun,<ref name=Grundahl/> and it is beginning to expand to become a giant.

== Etymology ==

In the catalogue of stars in the ''Calendarium of Al Achsasi Al Mouakket'', this star was designated ''Marfak Al Jathih Al Aisr'', which was translated into [[Latin]] as ''Cubitum Sinistrum Ingeniculi'', meaning ''the left elbow of kneeling man''.<ref name=knobel1895/>

In [[Chinese astronomy|Chinese]], {{lang|zh|天市左垣}} ({{lang|zh-Latn|Tiān Shì Zuǒ Yuán}}), the ''[[Heavenly Market enclosure|Left Wall of Heavenly Market Enclosure]]'', refers to an asterism which represents eleven old states in China, marking the left borderline of the enclosure, consisting of μ Herculis, [[Delta Herculis|δ Herculis]], [[Lambda Herculis|λ Herculis]], [[Omicron Herculis|ο Herculis]], [[112 Herculis]], [[Zeta Aquilae|ζ Aquilae]], [[Theta1 Serpentis|θ<sup>1</sup> Serpentis]], [[Eta Serpentis|η Serpentis]], [[Nu Ophiuchi|ν Ophiuchi]], [[Xi Serpentis|ξ Serpentis]] and [[Eta Ophiuchi|η Ophiuchi]].<ref>{{in lang|zh}} ''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}}.</ref> Consequently, the [[Chinese star names|Chinese name]] for μ Herculis itself is {{lang|zh|天市左垣三}} ({{lang|zh-Latn|Tiān Shì Zuǒ Yuán sān}}, {{langx|en|the Third Star of Left Wall of Heavenly Market Enclosure}}), represent ''Jiuhe'' (九河, lit. meaning ''nine rivers''), possibly for [[Jiujiang]], the prefecture-level city in Jiangxi, China, which is the same literally meaning with ''Jiuhe''.<ref>{{in lang|zh}} [http://aeea.nmns.edu.tw/2006/0606/ap060623.html AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 23 日] {{Webarchive|url=https://web.archive.org/web/20210515003305/http://aeea.nmns.edu.tw/2006/0606/ap060623.html |date=2021-05-15 }}</ref><ref>{{in lang|zh}} [http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/e_research_chinengstarzone_b.htm#HeavenlyMarketEnclosure English-Chinese Glossary of Chinese Star Regions, Asterisms and Star Name] {{webarchive|url=https://web.archive.org/web/20100810114313/http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/e_research_chinengstarzone_b.htm |date=2010-08-10 }}, Hong Kong Space Museum. Accessed on line November 23, 2010.</ref> From this Chinese title, the name ''Kew Ho'' appeared.<ref>[https://penelope.uchicago.edu/Thayer/E/Gazetteer/Topics/astronomy/_Texts/secondary/ALLSTA/Hercules*.html Star Name - R.H. Allen p. 238]</ref>

== Star system ==
Mu Herculis is a quadruple star system. The brightest star is a well-studied [[G-type star|G-type]] [[subgiant]], whose parameters are precisely determined from [[asteroseismology]].<ref name=Grundahl/> It was believed to be a close binary with a low-mass stellar or a large substellar companion. This was confirmed when low-mass companion was resolved using [[near-infrared spectroscopy]].<ref name=Roberts/> The companion star is a [[red dwarf]] with a [[spectral type]] of M4V and a mass of {{solar mass|0.32}}.<ref name=Roberts/> This pair is also known as Mu<sup>1</sup> Herculis.

The secondary component, also known as Mu<sup>2</sup> Herculis,<ref name=Simbad2>{{cite simbad|title=* mu.02 Her|access-date=24 May 2017}}</ref> consists of a pair of stars that orbit about each other with a period of about 43 years.<ref name=aj121_6_3254/> Mu Herculis A and the binary pair B-C are separated by some 35 arcseconds.<ref name=Simbad1>{{cite simbad|title=* mu. Her|access-date=24 May 2017}}</ref> The stars B and C, which orbit each other, are separated from each other by 1.385 arcseconds, and have a slightly eccentric orbit, at 0.1796.<ref name=ORB6/>

==See also==
* [[List of star systems within 25–30 light-years]]

==References==
{{reflist|30em|refs=

<ref name=aaa474_2_653>{{citation | last1=van Leeuwen | first1=F. | title=Validation of the new Hipparcos reduction | journal=Astronomy and Astrophysics | volume=474 | issue=2 |date=November 2007 | pages=653–664 | doi=10.1051/0004-6361:20078357 | bibcode=2007A&A...474..653V | arxiv=0708.1752 | s2cid=18759600 }}</ref>

<ref name=aj121_6_3254>{{citation | display-authors=1 | title=Search for Faint Companions to Nearby Solar-like Stars using the Adaptive Optics System at Mount Wilson Observatory | last1=Turner | first1=Nils H. | last2=ten Brummelaar | first2=Theo A. | last3=McAlister | first3=Harold A. | last4=Mason | first4=Brian D. | last5=Hartkopf | first5=William I. | last6=Roberts | first6=Lewis C. Jr. | journal=The Astronomical Journal | volume= 121 | issue=6 | pages=3254–3258 |date=June 2001 | doi=10.1086/321075 | bibcode=2001AJ....121.3254T | doi-access=free }}</ref>

<ref name=knobel1895>{{citation | 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| doi-access=free }}</ref>

<ref name=na15_4_367>{{citation | title=Models of μ Her with asteroseismic constraints | last1=Yang | first1=Wuming | last2=Meng | first2=Xiangcun | journal=New Astronomy | volume=15 | issue= 4 | pages=367–372 |date=April 2010 | doi=10.1016/j.newast.2009.11.001 | bibcode=2010NewA...15..367Y |arxiv = 0911.0749 | s2cid=119121800 }}</ref>

<ref name=baas25_1319>{{citation | last1=Garrison | first1=R. F. | title=Anchor Points for the MK System of Spectral Classification | journal=Bulletin of the American Astronomical Society | volume=25 | page=1319 | date=December 1993 | bibcode=1993AAS...183.1710G | url=http://www.astro.utoronto.ca/~garrison/mkstds.html | access-date=2012-02-04 | archive-date=2019-06-25 | archive-url=https://web.archive.org/web/20190625094716/http://www.astro.utoronto.ca/~garrison/mkstds.html }}</ref>

}}


==External links==
==External links==
*Jim Kaler's Stars, University of Illinois: [http://stars.astro.illinois.edu/sow/muher.html MU HER (Mu Herculis)]
* [http://www.solstation.com/stars/mu-herc4.htm Mu Hercules4] at SolStation.
* [http://www.astro.uiuc.edu/projects/sow/muher.html Mu Herculis] by Professor Jim Kaler.
*SolStation: [http://www.solstation.com/stars/mu-herc4.htm Mu Herculis 4]
[[Category:Hercules constellation]]


{{Stars of Hercules}}
{{star-stub}}


[[sk:Mí Herculis]]
{{DEFAULTSORT:Mu Herculis}}
[[Category:Hercules (constellation)]]
[[Category:Multiple star systems|4]]
[[Category:G-type subgiants]]
[[Category:M-type main-sequence stars]]
[[Category:Solar-type stars|Herculis, Mu]]
[[Category:Bayer objects|Herculis, Mu]]
[[Category:Flamsteed objects|Herculis, 086]]
[[Category:Hipparcos objects|086974]]
[[Category:Bright Star Catalogue objects|6623]]
[[Category:Gliese and GJ objects|0695]]
[[Category:Durchmusterung objects]]
[[Category:Henry Draper Catalogue objects|161797]]

Latest revision as of 04:21, 15 November 2024

Mu Herculis

Historical view of the Hercules constellation showing Mu Herculis (μ Her) as one of stars in the hero's elbow.
Observation data
Epoch J2000      Equinox J2000
Constellation Hercules
μ Her Aab (μ1 Her)
Right ascension 17h 46m 27.52667s[1]
Declination +27° 43′ 14.4379″[1]
Apparent magnitude (V) 3.417 ± 0.014[1]
μ Her BC (μ2 Her)
Right ascension 17h 46m 25.079s[2]
Declination +27° 43′ 01.45″[2]
Apparent magnitude (V) 10.2 / 10.7[3]
Characteristics
μ Her Aab
Spectral type G5IV[4] / M4V[5]
U−B color index +0.40[6]
B−V color index +0.76[6]
μ Her BC
Spectral type M3.5V[7]
U−B color index +1.00[6]
B−V color index +1.50[6]
Astrometry
μ Her Aab
Radial velocity (Rv)−17.07 ± 0.12[8] km/s
Proper motion (μ) RA: −291.66[1] mas/yr
Dec.: −749.60[1] mas/yr
Parallax (π)120.33 ± 0.16 mas[1]
Distance27.11 ± 0.04 ly
(8.31 ± 0.01 pc)
Absolute magnitude (MV)3.82 ± 0.02[8]
μ Her BC
Proper motion (μ) RA: −343.35[9] mas/yr
Dec.: −743.88[9] mas/yr
Parallax (π)119.8871 ± 0.2055 mas[10]
Distance27.21 ± 0.05 ly
(8.34 ± 0.01 pc)
Absolute magnitude (MV)+10.26[11]
Position (relative to μ Her Aab)[12]
Componentμ Her BC
Angular distance35″
Orbit[5]
Primaryμ Her Aa
Companionμ Her Ab
Period (P)98.9 ± 22.7 yr
Semi-major axis (a)2.9 ± 0.3″
Eccentricity (e)0.44 ± 0.06
Inclination (i)62.82 ± 4.66°
Longitude of the node (Ω)80.4 ± 1.7°
Periastron epoch (T)B 1921.1 ± 23.8
Argument of periastron (ω)
(secondary)		214 ± 16°
Semi-amplitude (K1)
(primary)		1.12 ± 0.10 km/s
Orbit[3]
Primaryμ Her B
Companionμ Her C
Period (P)43.127 ± 0.013 yr
Semi-major axis (a)1.385 ± 0.038″
Eccentricity (e)0.1796 ± 0.0009
Inclination (i)66.06 ± 0.15°
Longitude of the node (Ω)60.07 ± 0.17°
Periastron epoch (T)B 2008.335 ± 0.073
Argument of periastron (ω)
(secondary)		172.85 ± 0.64°
Details
μ Her Aa
Mass1.11 ± 0.01[8] M☉
Radius1.73 ± 0.02[8] R☉
Luminosity2.54 ± 0.08[8] L☉
Surface gravity (log g)3.98 ± 0.10[8] cgs
Temperature5560 ± 80[8] K
Metallicity [Fe/H]0.28 ± 0.07[8] dex
Rotation52+3
−1 d[8]
Rotational velocity (v sin i)1.7 ± 0.4[8] km/s
Age7.8+0.3
−0.4[8] Gyr
μ Her Ab
Mass0.32[5] M☉
μ Her B
Mass0.44[13] M☉
Radius0.60[14] R☉
Luminosity0.087[14] L☉
Temperature4,050[14] K
Metallicity [Fe/H]+0.21[14] dex
μ Her C
Mass0.39[13] M☉
Other designations
86 Herculis, Gl 695, HR 6623, BD+27° 2888, HD 161797, LHS 3326/3325, LTT 15266, SAO 85397, FK5 667, LFT 1374, GC 24138, ADS 10786, HIP 86974.[15]
Database references
SIMBADμ Her Aab
μ Her BC

Mu Herculis (μ Herculis) is a nearby quadruple star system about 27.1 light years from Earth in the constellation Hercules. Its main star, Mu Herculis A is fairly similar to the Sun although more highly evolved with a stellar classification of G5 IV. Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified.[16] Its mass is about 1.1 times that of the Sun,[8] and it is beginning to expand to become a giant.

Etymology

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In the catalogue of stars in the Calendarium of Al Achsasi Al Mouakket, this star was designated Marfak Al Jathih Al Aisr, which was translated into Latin as Cubitum Sinistrum Ingeniculi, meaning the left elbow of kneeling man.[17]

In Chinese, 天市左垣 (Tiān Shì Zuǒ Yuán), the Left Wall of Heavenly Market Enclosure, refers to an asterism which represents eleven old states in China, marking the left borderline of the enclosure, consisting of μ Herculis, δ Herculis, λ Herculis, ο Herculis, 112 Herculis, ζ Aquilae, θ1 Serpentis, η Serpentis, ν Ophiuchi, ξ Serpentis and η Ophiuchi.[18] Consequently, the Chinese name for μ Herculis itself is 天市左垣三 (Tiān Shì Zuǒ Yuán sān, English: the Third Star of Left Wall of Heavenly Market Enclosure), represent Jiuhe (九河, lit. meaning nine rivers), possibly for Jiujiang, the prefecture-level city in Jiangxi, China, which is the same literally meaning with Jiuhe.[19][20] From this Chinese title, the name Kew Ho appeared.[21]

Star system

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Mu Herculis is a quadruple star system. The brightest star is a well-studied G-type subgiant, whose parameters are precisely determined from asteroseismology.[8] It was believed to be a close binary with a low-mass stellar or a large substellar companion. This was confirmed when low-mass companion was resolved using near-infrared spectroscopy.[5] The companion star is a red dwarf with a spectral type of M4V and a mass of 0.32 M☉.[5] This pair is also known as Mu1 Herculis.

The secondary component, also known as Mu2 Herculis,[12] consists of a pair of stars that orbit about each other with a period of about 43 years.[22] Mu Herculis A and the binary pair B-C are separated by some 35 arcseconds.[15] The stars B and C, which orbit each other, are separated from each other by 1.385 arcseconds, and have a slightly eccentric orbit, at 0.1796.[3]

See also

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References

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  1. ^ a b c d e f 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. ^ a b Cutri, R. M.; et al. (2003). "2MASS All-Sky Catalog of Point Sources". VizieR On-line Data Catalog. 2246. Bibcode:2003yCat.2246....0C.
  3. ^ a b c "Sixth Catalog of Orbits of Visual Binary Stars". United States Naval Observatory. Archived from the original on 1 August 2017. Retrieved 23 March 2017.
  4. ^ Yang, Wuming; Meng, Xiangcun (April 2010), "Models of μ Her with asteroseismic constraints", New Astronomy, 15 (4): 367–372, arXiv:0911.0749, Bibcode:2010NewA...15..367Y, doi:10.1016/j.newast.2009.11.001, S2CID 119121800
  5. ^ a b c d e Roberts Jr., Lewis C.; Mason, Brian D.; Aguilar, Jonathan; Carson, Joseph; Crepp, Justin; Beichman, Charles; Brenner, Douglas; Burruss, Rick; Cady, Eric; Luszcz-Cook, Statia; Dekany, Richard; Hillenbrand, Lynne; Hinkley, Sasha; King, David; Lockhart, Thomas G.; Nilsson, Ricky; Oppenheimer, Rebecca; Parry, Ian R.; Pueyo, Laurent; Rice, Emily L.; Sivaramakrishnan, Anand; Soummer, Rémi; Vasisht, Gautam; Veicht, Aaron; Wang, Ji; Zhai, Chengxing; Zimmerman, Neil T. (2016). "Characterization of the Companion to μ Her". The Astronomical Journal. 151 (6): 169. arXiv:1604.06494. Bibcode:2016AJ....151..169R. doi:10.3847/0004-6256/151/6/169. S2CID 43403927.
  6. ^ a b c d Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data: 0. Bibcode:1986EgUBV........0M.
  7. ^ Alonso-Floriano, F. J.; Morales, J. C.; Caballero, J. A.; Montes, D.; Klutsch, A.; Mundt, R.; Cortés-Contreras, M.; Ribas, I.; Reiners, Ansgar; Amado, P. J.; Quirrenbach, A.; Jeffers, S. V. (2015). "CARMENES input catalogue of M dwarfs" (PDF). Astronomy & Astrophysics. 577: A128. arXiv:1502.07580. Bibcode:2015A&A...577A.128A. doi:10.1051/0004-6361/201525803. S2CID 53135130.[permanent dead link‍]
  8. ^ a b c d e f g h i j k l m Grundahl, F.; Andersen, M. Fredslund; Christensen-Dalsgaard, J.; Antoci, V.; Kjeldsen, H.; Handberg, R.; Houdek, G.; Bedding, T. R.; Pallé, P. L.; Jessen-Hansen, J.; Aguirre, V. Silva; White, T. R.; Frandsen, S.; Albrecht, S.; Andersen, M. I.; Arentoft, T.; Brogaard, K.; Chaplin, W. J.; Harpsøe, K.; Jørgensen, U. G.; Karovicova, I.; Karoff, C.; Rasmussen, P. Kjærgaard; Lund, M. N.; Lundkvist, M. Sloth; Skottfelt, J.; Norup Sørensen, A.; Tronsgaard, R.; Weiss, E. (2017). "First Results from the Hertzsprung SONG Telescope: Asteroseismology of the G5 Subgiant Star μ Herculis". The Astrophysical Journal. 836 (1): 142. arXiv:1701.03365. Bibcode:2017ApJ...836..142G. doi:10.3847/1538-4357/836/1/142. S2CID 119480210.
  9. ^ a b Röser, S.; Schilbach, E.; Schwan, H.; Kharchenko, N. V.; Piskunov, A. E.; Scholz, R.-D. (2008). "PPM-Extended (PPMX) – a catalogue of positions and proper motions". Astronomy and Astrophysics. 488 (1): 401. arXiv:0806.1009. Bibcode:2008A&A...488..401R. doi:10.1051/0004-6361:200809775. S2CID 17350617.
  10. ^ Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  11. ^ Davison, Cassy L.; White, R. J.; Henry, T. J.; Riedel, A. R.; Jao, W. -C.; Bailey, J. I.; Quinn, S. N.; Cantrell, J. R.; Subasavage, J. P.; Winters, J. G. (2015). "A 3D Search for Companions to 12 Nearby M Dwarfs". The Astronomical Journal. 149 (3): 106. arXiv:1501.05012. Bibcode:2015AJ....149..106D. doi:10.1088/0004-6256/149/3/106. S2CID 9719725.
  12. ^ a b "* mu.02 Her". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 24 May 2017.
  13. ^ a b "Multiple Star Catalog". Archived from the original on 2018-12-03. Retrieved 2018-12-02.
  14. ^ a b c d Gaidos, E.; Mann, A. W.; Lépine, S.; Buccino, A.; James, D.; Ansdell, M.; Petrucci, R.; Mauas, P.; Hilton, E. J. (2014). "Trumpeting M dwarfs with CONCH-SHELL: A catalogue of nearby cool host-stars for habitable exoplanets and life". Monthly Notices of the Royal Astronomical Society. 443 (3): 2561. arXiv:1406.7353. Bibcode:2014MNRAS.443.2561G. doi:10.1093/mnras/stu1313.
  15. ^ a b "* mu. Her". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 24 May 2017.
  16. ^ Garrison, R. F. (December 1993), "Anchor Points for the MK System of Spectral Classification", Bulletin of the American Astronomical Society, 25: 1319, Bibcode:1993AAS...183.1710G, archived from the original on 2019-06-25, retrieved 2012-02-04
  17. ^ Knobel, E. B. (June 1895), "Al Achsasi Al Mouakket, on a catalogue of stars in the Calendarium of Mohammad Al Achsasi Al Mouakket", Monthly Notices of the Royal Astronomical Society, 55 (8): 429, Bibcode:1895MNRAS..55..429K, doi:10.1093/mnras/55.8.429
  18. ^ (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.
  19. ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 23 日 Archived 2021-05-15 at the Wayback Machine
  20. ^ (in Chinese) English-Chinese Glossary of Chinese Star Regions, Asterisms and Star Name Archived 2010-08-10 at the Wayback Machine, Hong Kong Space Museum. Accessed on line November 23, 2010.
  21. ^ Star Name - R.H. Allen p. 238
  22. ^ Turner, Nils H.; et al. (June 2001), "Search for Faint Companions to Nearby Solar-like Stars using the Adaptive Optics System at Mount Wilson Observatory", The Astronomical Journal, 121 (6): 3254–3258, Bibcode:2001AJ....121.3254T, doi:10.1086/321075
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