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112 Herculis

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112 Herculis
Location of 112 Herculis (circled)
Observation data
EpochJ2000EquinoxJ2000
Constellation Hercules
Right ascension 18h52m16.428s[1]
Declination +21° 25′ 30.51″[1]
Apparent magnitude(V) 5.43[2]
Characteristics
Spectral type B9p Hg[3](B6.5V + A2V)[4]
B−Vcolor index −0.068±0.008[2]
Astrometry
Radial velocity(Rv)−19.8±0.9[5]km/s
Proper motion(μ)RA:−7.526mas/yr[1]
Dec.:−10.231mas/yr[1]
Parallax(π)7.8558 ± 0.0728mas[1]
Distance415 ± 4ly
(127 ± 1pc)
Absolute magnitude(MV)−0.04[2]
Orbit[6]
Period(P)6.36246±0.00002 d
Eccentricity(e)0.11±0.03
Periastronepoch(T)2,452,540.11±0.03JD
Argument of periastron(ω)
(secondary)		198±2°
Semi-amplitude(K1)
(primary)		17.0±0.6 km/s
Semi-amplitude(K2)
(secondary)		35±2 km/s
Details
Primary
Mass~5.0[4]M☉
Radius2.888[7]R☉
Luminosity203+4
−3[7]L☉
Surface gravity(logg)4.1[8]cgs
Temperature12,853±89[7]K
Rotation12.419 d[7]
Rotational velocity(vsini)20[9]km/s
Secondary
Mass~2.5[4]M☉
Surface gravity(logg)4.2[8]cgs
Other designations
112 Her,BD+21°3582,GC25895,HD174933,HIP92614,HR7113,SAO86521,WDSJ18523+2126[10]
Database references
SIMBADdata

112 Herculisis abinary starsystem in the northernconstellationofHercules.It is dimly visible to the naked eye with a combinedapparent visual magnitudeof 5.43.[2]The secondary component is about two magnitudes fainter than the primary star.[4]The distance to this system is approximately 415light yearsbased onparallaxmeasurements.[1]It is drifting closer to the Sun with aradial velocityof −20 km/s.[5]

The binary character of this system was discovered byW. F. Meyerin 1926. By measuring the variation in velocity of the primary component, he determined anorbital periodof 6.3624 days.[11]K. Osawain 1959 found astellar classificationof A4 III for the pair.[12]W. P. Bidelmanobserved that the primary has unusually stronglinesof ionized phosphorus, and it was assigned to the class ofpeculiar manganese starsbyW. L. W. SargentandL. Searlein 1962, with a resulting spectral type of B9.[13]No evidence was found for a strongmagnetic fieldbyP. S. Contiin 1970.[14]

Alight curvefor 112 Herculis, plotted fromTESSdata[15]

In 1969,A. Cowleyand associates found a stellar class of B9p Hg for this system, indicating a peculiar star with an abundance anomaly of mercury.[3]C. E. Seligmanin 1970 determined amass ratioof 2.06±0.17 for the pair, which supported individual stellar classes of B7V and A3V formain sequencecomponents. The sharpness of the spectral lines suggested that at least the primary is rotating synchronously with its orbital period.[16]A more detailed analysis by Seligman andL. H. Allenlater in 1970 refined the classifications to B6.5V and A2V. The elemental abundances for both stars appeared similar, although the secondary abundances were more uncertain.[4]

In 1975, the primary was classified as amercury-manganese starbyC. R. CowleyandG. C. L. Aikman.[17]T. A. Ryabchikovaand associates in 1996 refined the mass ratio to 1.98±0.03. The primary showed significant deficiencies of helium and mercury, but a large overabundance of iron. The secondary component displayed abundances similar to anAm star.[8]This is a double-linedspectroscopic binarysystem with an orbital period of 6.36246 days and aneccentricity(ovalness) of 0.11.[6]As of 2021, measurements by theTESSspace telescopeshow a rotation period of 12.4 days for the primary, suggesting that it is not rotating synchronously with its orbit.[7]Some variability influxwas recorded by TESS, but this is due to orbital motion – the stars themselves do not appear to bevariable.[18]

References

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  1. ^abcdeBrown, A. G. A.;et al. (Gaia collaboration) (2021)."GaiaEarly 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.S2CID227254300.(Erratum:doi:10.1051/0004-6361/202039657e).Gaia EDR3 record for this sourceatVizieR.
  2. ^abcdAnderson, 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,S2CID119257644.
  3. ^abCowley, A.; et al. (April 1969), "A study of the bright A stars. I. A catalogue of spectral classifications",Astronomical Journal,74:375–406,Bibcode:1969AJ.....74..375C,doi:10.1086/110819.
  4. ^abcdeSeligman, Courtney E.; Aller, L. H. (December 1970), "A Model Atmosphere Analysis of the Binary 112 Herculis",Astrophysics and Space Science,9(3): 461–481,Bibcode:1970Ap&SS...9..461S,doi:10.1007/BF00649584,S2CID122876855.
  5. ^abWilson, Ralph Elmer (1953), "General catalogue of stellar radial velocities",Washington,Carnegie Institution of Washington: 0,Bibcode:1953GCRV..C......0W.
  6. ^abCatanzaro, G.; Leto, P. (March 2004), "Orbital solutions for SB2 systems with a HgMn component",Astronomy and Astrophysics,416(2): 661–668,Bibcode:2004A&A...416..661C,doi:10.1051/0004-6361:20034445,S2CID62892090.
  7. ^abcdeKochukhov, O.; et al. (October 2021), "TESS survey of rotational and pulsational variability of mercury-manganese stars",Monthly Notices of the Royal Astronomical Society,506(4): 5328–5344,arXiv:2107.09096,Bibcode:2021MNRAS.506.5328K,doi:10.1093/mnras/stab2107.
  8. ^abcRyabchikova, T. A.; et al. (December 1996), "Elemental abundance analyses with DAO spectrograms - XIV. The double-lined spectroscopic binary 112 Herculis",Monthly Notices of the Royal Astronomical Society,283(4): 1115–1132,Bibcode:1996MNRAS.283.1115R,doi:10.1093/mnras/283.4.1115.
  9. ^Abt, Helmut A.; et al. (July 2002), "Rotational Velocities of B Stars",The Astrophysical Journal,573(1): 359–365,Bibcode:2002ApJ...573..359A,doi:10.1086/340590.
  10. ^"112 Her".SIMBAD.Centre de données astronomiques de Strasbourg.Retrieved2022-10-24.
  11. ^Meyer, William Ferdinand (1926), "The orbit of the spectroscopic binary 112 Herculis",Lick Observatory Bulletin,381,Berkeley: University of California Press: 165–167,Bibcode:1926LicOB..12..165M,doi:10.5479/ADS/bib/1926LicOB.12.165M.
  12. ^Osawa, Kiyoteru (July 1959), "Spectral Classification of 533 B8-A2 Stars and the Mean Absolute Magnitude of A0 V Stars",Astrophysical Journal,130:159,Bibcode:1959ApJ...130..159O,doi:10.1086/146706.
  13. ^Sargent, Wallace L. W.; Searle, Leonard (September 1962), "Studies of the Peculiar A Stars. I. The Oxygen-Abundance Anomaly",Astrophysical Journal,136:408,Bibcode:1962ApJ...136..408S,doi:10.1086/147393.
  14. ^Conti, Peter S. (June 1970), "Zeeman Measures of Four Double-Lined Peculiar A Stars",Astrophysical Journal,160:1077,Bibcode:1970ApJ...160.1077C,doi:10.1086/150495.
  15. ^MAST: Barbara A. Mikulski Archive for Space Telescopes,Space Telescope Science Institute,retrieved27 October2022.
  16. ^Seligman, Courtney E. (February 1970), "A Mass Ratio for 112 Herculis",Publications of the Astronomical Society of the Pacific,82(484): 128,Bibcode:1970PASP...82..128S,doi:10.1086/128894,S2CID121129664.
  17. ^Cowley, C. R.; Aikman, G. C. L. (August 1975), "A study of the lambda 3984 feature in the mercury-manganese stars",Publications of the Astronomical Society of the Pacific,87:513–521,Bibcode:1975PASP...87..513C,doi:10.1086/129801,S2CID121306556.
  18. ^Monier, Richard (October 2022), "The Behavior of HgMn Stars in the Far UV—Paper 16: HD 174933",Research Notes of the AAS,6(10): 218,Bibcode:2022RNAAS...6..218M,doi:10.3847/2515-5172/ac9afe,S2CID253018177.
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