Reconstruction of Cepheid Radial Velocity Curves from the shape of the V-band Light Curves

Abstract

This paper aims to develop the first method to reconstruct the shape of the RV curves of short-period fundamental-mode Cepheids, based exclusively on their pulsation period and the morphology of their $V$-band light curves (LCs). We compiled a dataset of high-quality spectroscopic and photometric measurements from the literature for 81 short-period fundamental-mode Galactic Cepheids up to a pulsation period of 8\,days, enabling precise determination of the Fourier parameters and their uncertainties. We investigated correlations between LC and RV Fourier parameters and used these relations to reconstruct the RV curves. We further assessed the accuracy of these reconstructions by examining potential metallicity effects with an additional dataset of 23 metal-poor Cepheids. For pulsation periods between 3.5 and 7.0\,days, we found tight correlations between different combinations of LC and RV Fourier parameters up to order 7, in particular $R_{21}(RV)/R_{21}(LC)$ and $R_{31}(RV)/R_{31}(LC)$ are correlated with the pulsation period. These relationships enable the reconstruction of RV curves of Cepheids with their LC. The reconstructed curve has an uncertainty of about 0.60${\mathrm{km}\mathrm{s}}^{-1}$ relative to the Fourier fit of true spectroscopic RV measurements. For individual Cepheids, the reconstructed RV curves integrated along the pulsation cycle (i.e. the linear radius variations) are accurate to less than 1\% and precise to within 4.16\% in comparison to the integrated true spectroscopic RV curves. This approach provides a valuable tool for the reconstruction of RV curves for extragalactic Cepheids through photometric data alone. It opens the road to a purely photometric parallax-of-pulsation method in the context of photometric surveys, such as the Vera Rubin Telescope.

Accepted for publication in Astronomy and Astrophysics

References in corpus (26)

• The Astropy Project: Sustaining and Growing a Community-oriented Open-source Project and the Latest Major Release (v5.0) of the Core Package
• Gaia Data Release 3: Summary of the content and survey properties
• Modules for Experiments in Stellar Astrophysics (MESA): Pulsating Variable Stars, Rotation, Convective Boundaries, and Energy Conservation
• Gaia Data Release 3 Properties and validation of the radial velocities
• The influence of chemical composition on the properties of Cepheid stars. II-The iron content
• New NIR light-curve templates for classical Cepheids
• On the Variation of Fourier Parameters for Galactic and LMC Cepheids at Optical, Near-Infrared and Mid-Infrared Wavelengths
• Kiso Supernova Survey (KISS): Survey Strategy
• Vetting Galactic Leavitt Law Calibrators using Radial Velocities: On the Variability, Binarity, and Possible Parallax Error of 19 Long-period Cepheids
• Inspecting the Cepheid parallax of pulsation using Gaia EDR3 parallaxes. Projection factor and period-luminosity and period-radius relations
• Multiplicity of Galactic Cepheids from long-baseline interferometry. IV. New detected companions from MIRC and PIONIER observations
• Study of changes in the pulsation period of 148 Galactic Cepheid variables
• A thin shell of ionized gas explaining the IR excess of classical Cepheids
• Cepheids with giant companions. I. Revealing a numerous population of double-lined binary Cepheids
• The Cepheid Phase Lag Revisited
• VELOcities of CEpheids (VELOCE) I. High-precision radial velocities of Cepheids
• Probing Polaris' Puzzling Radial Velocity Signals - Pulsational (In-)Stability, Orbital Motion, and Bisector Variations
• Cepheid Variables in the Maser-Host Galaxy NGC 4258
• Period Change Rates in Large Magellanic Cloud Cepheids Revisited
• HARPS-N high spectral resolution observations of Cepheids II. The impact of the surface-brightness color relation on the Baade-Wesselink projection factor of eta Aql
• Metallicity estimation of MW, SMC and LMC classical Cepheids from the shape of the $V$- and $I$-band light curves
• Period Change Rates of Large Magellanic Cloud Cepheids using MESA
• VELOcities of CEpheids (VELOCE) II. Systematic Search for Spectroscopic Binary Cepheids
• Precise Fourier parameters of Cepheid Radial Velocity Curves
• Study of the effect of metallicity on the amplitudes of Cepheids
• The model fitting of Gaia DR3 Classical Cepheid light and radial velocity curves