112 Herculis is a binary star system in the northern constellation of Hercules. It is dimly visible to the naked eye with a combined apparent visual magnitude of 5.43.[2] The secondary component is about two magnitudes fainter than the primary star.[4] The distance to this system is approximately 415light years based on parallax measurements.[1] It is drifting closer to the Sun with a radial velocity of −20km/s.[5]
In 1969, A. Cowley and associates found a stellar class of B9pHg 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 mercury-manganese star by C. R. Cowley and G. C. L. Aikman.[17]T. A. Ryabchikova and 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 an Am star.[8] This is a double-lined spectroscopic binary system with an orbital period of 6.36246days and an eccentricity (ovalness) of 0.11.[6] As of 2021, measurements by the TESSspace telescope show a rotation period of 12.4days 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]
12Cowley, A.; etal. (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.
123Ryabchikova, T. A.; etal. (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.
↑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.
↑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.
↑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.
