Extended Data Figure 2: Parameterization of the helium profile in the envelope of a typical DB white dwarf model.
From: A large oxygen-dominated core from the seismic cartography of a pulsating white dwarf
The figure shows the local helium mass fraction, X(He), as a function of the fractional mass depth, log(q)?≡log[1−M(r)/M]. Along with the three quantities depicted in the plot—log(q1), log(q2) and X(He)env, as defined previously—there are two other hidden parameters that are related to the shape of the helium profile in the descent centred on log(q1) and in the descent centred on log(q2) (see text for details).
