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arXiv · 2609.17693

Predicting Macroturbulence in F/G/K Dwarfs to 100 m/s Precision

Jack Lubin·Erik Petigura·Kento Masuda·Samuel Halverson·Isabel Angelo·Daniel Huber·Michael L. Palumbo III·Songhu Wang·Xian-Yu Wang
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Abstract

We leverage the high resolution and spectral stability of the Keck Planet Finder (KPF) spectrograph to investigate macroturbulence broadening via the stellar cross-correlation function (CCF). As our calibration sample, we use main sequence benchmark slow-rotators v$\sin$i < 4 km/s where rotation rates were derived from the most robust asteroseismic mode splitting measurements, independent from spectral line broadening. We fit a linear relationship for macroturbulence as a function of derived $ν_{max}$, the frequency of maximum power due to stellar oscillations, with an RMS scatter of 90 m/s. Previous studies have calibrated macroturbulence against T$_{eff}$, but we find $ν_{max}$ to be a lower dispersion predictor by a factor of 4 indicating a deeper relationship between $ν_{max}$and convective motions.

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Jack Lubin, Erik Petigura, Kento Masuda, Samuel Halverson, Isabel Angelo, Daniel Huber, Michael L. Palumbo III, Songhu Wang, Xian-Yu Wang. 2026-09-15. Predicting Macroturbulence in F/G/K Dwarfs to 100 m/s Precision. https://arxiv.org/abs/2609.17693

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