Precise Fourier Parameters of Cepheid Radial Velocity Curves. Towards refining the Hertzsprung progression models

We present the Fourier fits of radial velocity (RV) curves for 218 Cepheids  (median fit dispersion of 0.72 km/s) as detailed in Hocdé et al. (2024, A&A, DOI: 10.1051/0004-6361/202347798). For each star, we meticulously selected RV measurements from the literature to ensure the highest precision in Fourier parameters. Further details of the modeling process are provided in the aforementioned paper. The sample includes 178 fundamental-mode Cepheids, 33 first-overtone Cepheids, and 7 Cepheids, pulsation mode of which is uncertain or undetermined with our criteria based on Fourier phase φ21. For each star, we provide a Fourier model, with the curve maximum fixed at a pulsation phase of φ = 0.3. These models, sampled 1000 times per pulsation cycle, are available in numerical form at Zenodo. The complete set of Fourier parameters and their associated uncertainties is available at CDS, which allows reproducing the curves. The fits are classified into three quality categories. RV curves of Quality 1  represent the highest precision fits, free of significant instabilities and with excellent phase coverage, while curves of Quality 1a show slight instabilities. Fits of Quality 2 offer useful Fourier parameters, but may be affected by stronger instabilities, larger scatter, or less than perfect phase coverage. For each star we plot the radial velocity measurements alongside the Fourier fit, enabling a quick assessment of the fit quality.