Mu Herculis

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
Declination	+27° 43′ 14.4379″
Apparent magnitude (V)	3.417 ± 0.014
	μ Her BC (μ2 Her)
Right ascension	17h 46m 25.079s
Declination	+27° 43′ 01.45″
Apparent magnitude (V)	10.2 / 10.7
Characteristics
μ Her Aab
Spectral type	G5IV / M4V
U−B color index	+0.40
B−V color index	+0.76
μ Her BC
Spectral type	M3.5V
U−B color index	+1.00
B−V color index	+1.50
Astrometry
μ Her Aab
Radial velocity (Rv)	−17.07 ± 0.12 km/s
Proper motion (μ)	RA: −291.66 mas/yr ; Dec.: −749.60 mas/yr
Parallax (π)	120.33±0.16 mas
Distance	27.11 ± 0.04 ly ; (8.31 ± 0.01 pc)
Absolute magnitude (MV)	3.82 ± 0.02
μ Her BC
Proper motion (μ)	RA: −343.35 mas/yr ; Dec.: −743.88 mas/yr
Parallax (π)	119.8871 ± 0.2055 mas
Distance	27.21 ± 0.05 ly ; (8.34 ± 0.01 pc)
Absolute magnitude (MV)	+10.26
Position (relative to μ Her Aab)
Component	μ Her BC
Angular distance	35″
Orbit
Primary	μ Her Aa
Companion	μ 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
Primary	μ Her B
Companion	μ 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
Mass	1.11 ± 0.01 M☉
Radius	1.704±0.016 R☉
Luminosity	2.557±0.026 L☉
Surface gravity (log g)	4.020±0.025 cgs
Temperature	5,596±22 K
Metallicity [Fe/H]	+0.26±0.04 dex
Rotation	52+3; −1 d
Rotational velocity (v sin i)	1.7 ± 0.4 km/s
Age	7.8+0.3; −0.4 Gyr
μ Her Ab
Mass	0.32 M☉
μ Her B
Mass	0.44 M☉
Radius	0.60 R☉
Luminosity	0.087 L☉
Temperature	4,050 K
Metallicity [Fe/H]	+0.21 dex
μ Her C
Mass	0.39 M☉
Radius	0.273±0.032 R☉
Temperature	3,100±32 K
Metallicity	= 0.39
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.
Database references
SIMBAD	μ 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.^[18] Its mass is about 1.1 times that of the Sun,^[8] and it is beginning to expand to become a giant.

^ ^a ^b ^c ^d ^e ^f Cite error: The named reference aaa474_2_653 was invoked but never defined (see the help page).
^ ^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.
^ ^a ^b "Sixth Catalog of Orbits of Visual Binary Stars". United States Naval Observatory. Archived from the original on 1 August 2017. Retrieved 23 March 2017.
^ Cite error: The named reference na15_4_367 was invoked but never defined (see the help page).
^ ^a ^b ^c 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.
^ ^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.
^ 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]}
^ ^a ^b ^c ^d ^e ^f ^g 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.
^ ^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.
^ 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.
^ 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.
^ Cite error: The named reference Simbad2 was invoked but never defined (see the help page).
^ ^a ^b ^c ^d ^e Cite error: The named reference Karovicova was invoked but never defined (see the help page).
^ ^a ^b "Multiple Star Catalog". Archived from the original on 2018-12-03. Retrieved 2018-12-02.
^ ^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.
^ ^a ^b ^c Cite error: The named reference Houdebine2019 was invoked but never defined (see the help page).
^ Cite error: The named reference Simbad1 was invoked but never defined (see the help page).
^ Cite error: The named reference baas25_1319 was invoked but never defined (see the help page).

[aaa474_2_653-1] ^ ^a ^b ^c ^d ^e ^f Cite error: The named reference aaa474_2_653 was invoked but never defined (see the help page).

[2MASS-2] Cutri, R. M.; et al. (2003). "2MASS All-Sky Catalog of Point Sources". VizieR On-line Data Catalog. 2246. Bibcode:2003yCat.2246....0C.

[ORB6-3] "Sixth Catalog of Orbits of Visual Binary Stars". United States Naval Observatory. Archived from the original on 1 August 2017. Retrieved 23 March 2017.

[na15_4_367-4] Cite error: The named reference na15_4_367 was invoked but never defined (see the help page).

[Roberts-5] 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.

[EgUBV-6] Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data: 0. Bibcode:1986EgUBV........0M.

[CARMENES-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]}

[Grundahl-8] ^ ^a ^b ^c ^d ^e ^f ^g 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.

[Roeser-9] 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.

[dr2bc-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.

[davison-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.

[Simbad2-12] Cite error: The named reference Simbad2 was invoked but never defined (see the help page).

[Karovicova-13] Cite error: The named reference Karovicova was invoked but never defined (see the help page).

[msc-14] "Multiple Star Catalog". Archived from the original on 2018-12-03. Retrieved 2018-12-02.

[gaidos-15] 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.

[Houdebine2019-16] Cite error: The named reference Houdebine2019 was invoked but never defined (see the help page).

[Simbad1-17] Cite error: The named reference Simbad1 was invoked but never defined (see the help page).

[baas25_1319-18] Cite error: The named reference baas25_1319 was invoked but never defined (see the help page).

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Observation data Epoch J2000 Equinox J2000
Historical view of the Hercules constellation showing Mu Herculis (μ Her) as one of stars in the hero's elbow.
Constellation	Hercules
μ Her Aab (μ¹ Her)
Right ascension	17^h 46^m 27.52667^s^[1]
Declination	+27° 43′ 14.4379″^[1]
Apparent magnitude (V)	3.417 ± 0.014^[1]
μ Her BC (μ² Her)
Right ascension	17^h 46^m 25.079^s^[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 (R_v)	−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]
Distance	27.11 ± 0.04 ly (8.31 ± 0.01 pc)
Absolute magnitude (M_V)	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]
Distance	27.21 ± 0.05 ly (8.34 ± 0.01 pc)
Absolute magnitude (M_V)	+10.26^[11]
Position (relative to μ Her Aab)^[12]

Component	μ Her BC
Angular distance	35″
Orbit^[5]
Primary	μ Her Aa
Companion	μ 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]
Primary	μ Her B
Companion	μ 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
Mass	1.11 ± 0.01^[8] `M`_☉
Radius	1.704±0.016^[13] `R`_☉
Luminosity	2.557±0.026^[13] `L`_☉
Surface gravity (log g)	4.020±0.025^[13] cgs
Temperature	5,596±22^[13] K
Metallicity [Fe/H]	+0.26±0.04^[13] dex
Rotation	52+3 −1 d^[8]
Rotational velocity (v sin i)	1.7 ± 0.4^[8] km/s
Age	7.8+0.3 −0.4^[8] Gyr
μ Her Ab
Mass	0.32^[5] `M`_☉

μ Her B
Mass	0.44^[14] `M`_☉
Radius	0.60^[15] `R`_☉
Luminosity	0.087^[15] `L`_☉
Temperature	4,050^[15] K
Metallicity [Fe/H]	+0.21^[15] dex
μ Her C
Mass	0.39^[14] `M`_☉
Radius	0.273±0.032^[16] `R`_☉
Temperature	3,100±32^[16] K
Metallicity	${\begin{smallmatrix}\left[{\ce {M}}/{\ce {H}}\right]\end{smallmatrix}}$ = 0.39^[16]
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.^[17]
Database references
SIMBAD	μ Her Aab
	μ Her BC