Location on an HRD of undermassive stars in the RGB phase for the MDS17 simulation. Crosses indicate undermassive lone primaries while thin diamonds mark undermassive secondary stars in a surviving binary. The color represents the current mass of each undermassive star, and empty markers indicate the ones where detection of oscillations is not likely (p_{seismo, bin} < 0.9). Gray points represent single stars from the simulation and are used to draw the main loci of the HRD.