2016ApJ...832...68G

The G7 IIIa single-lined spectroscopic binary, β Her, is studied with high-resolution, high-signal-to-noise spectra taken over 10 seasons from 23MR2000 to 10MY2009. Absolute radial velocities, corrected for convective blueshifts, are determined and new orbital parameters are derived. Line-depth ratios are used to measure temperature variation ∼2 K. A Fourier analysis is done for the line broadening, yielding a projected rotation velocity of 3.27 ± 0.20 km s^–1 and a radial-tangential macroturbulence dispersion of 6.43 ± 0.08 km s^–1. The "C" shaped bisector of Fe i λ6253 has its blue-most point at a relative flux level of 0.52, consistent with what is expected from β Her's absolute magnitude. The third-signature plot indicates granulation velocities 20% larger than the Sun's. Mapping the λ6253 line bisector onto the third-signature curve results in a flux deficit of 12.6 ± 1.0% that can be interpreted as arising from a temperature difference between granules and inter-granular lanes of 132 K. The flux deficit peaks near 5.5 km s^–1 from the line center, suggesting the velocity difference between granules and lanes is ∼20% larger than that found for recently analyzed K giants.