The Consequences of assuming m=0 for Global Model-fitting

Abstract

A recent re-analysis of Whole Earth Telescope observations of GD 358 obtained in 1990 suggests that asteroseismology of additional DBV white dwarfs can lead to independent constraints on the important, but poorly determined, ^{12}C(alpha,gamma)^{16}O nuclear reaction rate. Data exist for several other DBV white dwarfs, but relatively few modes are detected and there is often no multiplet structure to aid in the identification of the spherical harmonic indices (l,m). I use a new grid of one million DBV models covering a broad range of masses, temperatures, and surface helium layer masses to investigate the consequences of assuming m=0 for global model-fitting. I find that when the spherical degree is known and the rotation period is of order 1 day, the model-fitting procedure applied to modes with unknown m-values will still correctly identify the_families_ of possible solutions, and has a high probability of identifying the same globally optimal solution found when the m-value is known.