Image Details
Caption: Figure 2.
Fiducial hot (upper panel) and cool (lower panel) IS edges on the H-R diagram along with the midline (green curve). Data used to determine the edges (O24, Z = 0.004) are plotted with filled symbols of different shapes corresponding to crossing number. Overplotted are data for F-mode classical Cepheids from sources indicated in the top panel.
© 2026. The Author(s). Published by the American Astronomical Society.