The White Dwarf Initial-Final Mass Relation for Progenitor Stars from 0.85 to 7.5M⊙

We present the initial-final mass relation (IFMR) based on the self-consistent analysis of Sirius B and 79 white dwarfs from 13 star clusters. We have also acquired additional signal on eight white dwarfs previously analyzed in the NGC 2099 cluster field, four of which are consistent with membership. These re-observed white dwarfs have masses ranging from 0.72 to 0.97 M-circle dot, with initial masses from 3.0 to 3.65 M-circle dot, where the IFMR has an important change in slope that these new data help to observationally confirm. In total, this directly measured IFMR has small scatter (sigma = 0.06 M-circle dot) and spans from progenitors of 0.85 to 7.5 M-circle dot. Applying two different stellar evolutionary models to infer two different sets of white dwarf progenitor masses shows that, when the same model is also used to derive the cluster ages, the resulting IFMR has weak sensitivity to the adopted model at all but the highest initial masses (>5.5 M-circle dot). The nonlinearity of the IFMR is also clearly observed with moderate slopes at lower masses (0.08 M-final/M-initial) and higher masses (0.11 M-final/M-initial) that are broken up by a steep slope (0.19 M-final/M-initial) between progenitors from 2.85 to 3.6 M-circle dot. This IFMR shows total stellar mass loss ranges from 33% of M-initial at 0.83 M-circle dot to 83% of M-initial at 7.5 M-circle dot. Testing this total mass loss for dependence on progenitor metallicity, however, finds no detectable sensitivity across the moderate range of -0.15 < [Fe/H] < +0.15.