112 Herculis

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112 Herculis
Location of 112 Herculis (circled)
Observation data
J2000
Constellation Hercules
Right ascension 18h 52m 16.428s[1]
Declination +21° 25′ 30.51″[1]
Apparent magnitude (V) 5.43[2]
Characteristics
Spectral type B9p Hg[3] (B6.5V + A2V)[4]
B−V color index −0.068±0.008[2]
Distance
415 ± 4 ly
(127 ± 1 pc)
Absolute magnitude (MV)−0.04[2]
Semi-amplitude
(K1)
(primary)		17.0±0.6 km/s
Semi-amplitude (K2)
(secondary)		35±2 km/s
Details
Primary
Rotational velocity (v sin i)
20[9] km/s
Secondary
Mass~2.5[4] M☉
Surface gravity (log g)4.2[8] cgs
HR 7113, SAO 86521, WDS J18523+2126[10]
Database references
SIMBADdata

112 Herculis is a

light years based on parallax measurements.[1] It is drifting closer to the Sun with a radial velocity of −20 km/s.[5]

The binary character of this system was discovered by

lines of ionized phosphorus, and it was assigned to the class of peculiar manganese stars by W. L. W. Sargent and L. Searle in 1962, with a resulting spectral type of B9.[13] No evidence was found for a strong magnetic field by P. S. Conti in 1970.[14]

A light curve for 112 Herculis, plotted from TESS data[15]

In 1969, A. Cowley and associates found a stellar class of B9p Hg for this system, indicating a peculiar star with an abundance anomaly of mercury.[3] C. E. Seligman in 1970 determined a mass ratio of 2.06±0.17 for the pair, which supported individual stellar classes of B7V and A3V for main sequence components. 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 and L. H. Allen later 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 a

spectroscopic binary system with an orbital period of 6.36246 days and an eccentricity (ovalness) of 0.11.[6] As of 2021, measurements by the TESS space telescope show a rotation period of 12.4 days for the primary, suggesting that it is not rotating synchronously with its orbit.[7] Some variability in flux was recorded by TESS, but this is due to orbital motion – the stars themselves do not appear to be variable.[18]

References

  1. ^
    doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR
    .
  2. ^
    S2CID 119257644
    .
  3. ^
    doi:10.1086/110819
    .
  4. ^
    S2CID 122876855
    .
  5. ^
    Bibcode:1953GCRV..C......0W
    .
  6. ^
    S2CID 62892090
    .
  7. ^
    doi:10.1093/mnras/stab2107
    .
  8. ^
    doi:10.1093/mnras/283.4.1115
    .
  9. doi:10.1086/340590
    .
  10. ^ "112 Her". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2022-10-24.
  11. doi:10.5479/ADS/bib/1926LicOB.12.165M
    .
  12. doi:10.1086/146706
    .
  13. doi:10.1086/147393
    .
  14. doi:10.1086/150495
    .
  15. ^ MAST: Barbara A. Mikulski Archive for Space Telescopes, Space Telescope Science Institute, retrieved 27 October 2022.
  16. S2CID 121129664
    .
  17. S2CID 121306556
    .
  18. S2CID 253018177
    .
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