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

Abstract

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 reobserved white dwarfs have masses ranging from 0.72 to 0.97 M ⊙ , with initial masses from 3.0 to 3.65 M ⊙ , 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 (σ = 0.06 M ⊙ ) and spans from progenitors of 0.85 to 7.5 M ⊙ . 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 ⊙ ). The non-linearity 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 ⊙ . This IFMR shows total stellar mass loss ranges from 33% of M initial at 0.83 M ⊙ to 83% of M initial at 7.5 M ⊙ . 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.

Discovery of a pre-cataclysmic binary with unusual chromaticity of the eclipsed white dwarf by the GPX survey

“…Obtained system parameters allowed us to make some assumptions about the past and future of the GPX-TF16E-48. Based on the current mass of the WD and the semiempirical MIST model of initial-final mass relation of WDs from Cummings et al 2018, the progenitor mass was close to 2.9 M . After the main sequence stage, the primary evolved into a red giant forming a common envelope and then into a cooling white dwarf.…”

Impact of convective boundary mixing on the TP-AGB

“…In fact, when convection is included both at the CE and at the PDCZ, the final masses predicted by stellar evolution sequences fall well below the range indicated by semiempirical IFMR (Cummings et al 2018;El-Badry et al 2018). This suggests that either the TP-AGB is too short or that third dredge-up is too strong, inhibiting the growth of the H-free core during the TP-AGB.…”

“…However, it has also been shown that the inclusion of the value for f CBM as calibrated by upper main sequence stars at all convective boundaries (e.g. in Weiss & Ferguson 2009) results in such efficient third dredge-up that core growth is suppressed during the TP-AGB, leading to an IFMR that is in tension with observations, the predicted final mass being too low by ∼ 0.1...0.2M for initial masses in the range ∼ 2...4M (Salaris et al 2009;Cummings et al 2018;El-Badry et al 2018). CBM below the convective envelope (CE) plays two different roles.…”

“…The method of using white dwarfs in open clusters to construct a semi-empirical IFMR is a very useful tool for constraining the TP-AGB evolution. Examples of this method are Salaris et al (2009), Kalirai et al (2014), and Cummings et al (2018. In addition, El-Badry et al (2018) suggested a new method using GAIA data which might help to constrain the low-mass limit of the IFMR.…”

“…Initial-final mass relation for models where CBM has been applied at both boundaries for several values, black lines are all calculated at Z=0.02, all others at Z=0.008. Data points are from the semi-empirical IFMR of Cummings et al (2018). culated at Z=0.008 are also included.…”