AAVSO: American Association of Variable Star Observers

Using High Resolution Spectroscopy to Measure Cepheid Pulsation (Abstract)

Volume 49 number 1 (2021)

Kevin Gurney
14A Gladstone Road, Sheffield, S10 3GT, United Kingdom; k.gurney@shef.ac.uk

Abstract

(Abstract only) Using a high-resolution spectrograph like the Lhires III (Shelyak Instruments) it is possible, in principle, to measure radial velocities of the order of 1 km/s (Leadbeater, “Pushing the Limits,” AAVSO/BAA joint meeting, 2018). Thus, within these bounds, it should be feasible to measure radial velocities associated with Cepheid pulsation. However, extracting this component of the Doppler shift from a multiple system in which orbital components play a role is challenging; it requires information on the orbital ephemeris which, in turn, may require substantial observational and modelling effort. Fortunately, such information is available in a recent paper by Gallenne et al. 2018, Astrophys. J. for the target described here, V1334 Cyg. Here, I show how measurements of the wavelength of the Hα line of V1334 Cyg can be used, in conjunction with this published model, to determine a putative pulsation profile of this Cepheid variable, and validate it against AAVSO-derived photometry.