Post-common-envelope binaries from SDSS. IX: Constraining the common-envelope efficiency

By M. Zorotovic, M. Schreiber, B. Gänsicke, A. N. G'omez-Mor'an. 2010

202 citations recorded by the source corpus.

Context. Reconstructing the evolution of post-common-envelope binaries (PCEBs) consisting of a white dwarf and a main-sequence star can constrain current prescriptions of common-envelope (CE) evolution. This potential could so far not be fully exploited due to the small number of known systems and the inhomogeneity of the sample. Recent extensive follow-up observations of white dwarf/main-sequence binaries identified by the Sloan Digital Sky Survey (SDSS) paved the way for a better understanding of CE evolution. Aims. Analyzing the new sample of PCEBs we derive constraints on one of the most important parameters in the field of close compact binary formation, i.e. the CE efficiency α. Methods. After reconstructing the post-CE evolution and based on fits to stellar evolution calculations as well as a parametrized energy equation for CE evolution, we determine the possible evolutionary histories of the observed PCEBs. In contrast to most previous attempts we incorporate realistic approximations of the binding energy parameter λ. Each reconstructed CE history corresponds to a certain value of the mass of the white dwarf progenitor and – more importantly – the CE efficiency α. We also reconstruct CE evolution replacing the classical energy equation with a scaled angular momentum equation and compare the results obtained with both algorithms. Results. We find that all PCEBs in our sample can be reconstructed with the energy equation if the internal energy of the envelope is included. Although most individual systems have solutions for a broad range of values for α, only for α = 0.2–0.3 do we find simultaneous solutions for all PCEBs in our sample. If we adjust α to this range of values, the values of the angular momentum parameter γ cluster in a small range of values. In contrast if we fix γ to a small range of values that allows us to reconstruct all our systems, the possible ranges of values for α remains broad for individual systems. Conclusions. The classical parametrized energy equation seems to be an appropriate prescription of CE evolution and turns out to constrain the outcome of the CE evolution much more than the alternative angular momentum equation. If there is a universal value of the CE efficiency, it should be in the range of α = 0.2–0.3. We do not find any indications for a dependence of α on the mass of the secondary star or the final orbital period.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/7068cc0a9e4c92d9832d2caf849b94161fc08572

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Citations in the corpus

Dawes Review 6: The Impact of Companions on Stellar Evolution (2016, unknown): “…at finding what the efficiency of the CE might be have used known post-CE systems for which the pre-CE configuration could be reconstructed (e.g., Zorotovic et al., 2010; De Marco et al., 2011) or have used population synthesis codes with different CE efficiency prescriptions in the hope of…”
A circumbinary disc in the final stages of common envelope and the core-degenerate scenario for Type Ia supernovae (2011, background): “Zorotovic et al. (2010) also come into the conclusion that αCE < 1.”
SIMULATING THE COMMON ENVELOPE PHASE OF A RED GIANT USING SMOOTHED-PARTICLE HYDRODYNAMICS AND UNIFORM-GRID CODES (2011, result): “We now compare the numerical results with a sample of 61 observed post-CE systems listed in Zorotovic et al. (2010) and De Marco et al. (2011).”
Theoretical uncertainties of the Type Ia supernova rate (2014, background): “Different groups determine a CE efficiency smaller than 1 after fitting theαce-prescription to a population of observed post-CE binaries (Zorotovic et al. 2010; De Marco et al. 2011; Davis et al. 2012).”
Common envelope evolution: where we stand and how we can move forward (2012, methodology): “Namely, for larger M2/Mg the average value of αCE is smaller, as also found by Davis et al. (2011) (although Zorotovic et al. 2010 do not find indications for a dependence of α on the mass of the companion; also, there are enormous observational selection effects favoring short orbital periods).”
THE ROTATION RATES OF MASSIVE STARS: THE ROLE OF BINARY INTERACTION THROUGH TIDES, MASS TRANSFER, AND MERGERS (2012, methodology): “To treat common envelope situations we follow Hurley et al. (2002) we use choose a common envelope ejection efficiency parameter αCE = 0.2 in agreement with studies of binary systems in planetary nebulae (Zorotovic et al. 2010; Davis et al. 2010; De Marco et al. 2011).”
COSMIC Variance in Binary Population Synthesis (2019, background): “…the impact of observed space densities (Nissanke et al. 2012), the effect of different binary evolution models on the observed population (Zorotovic et al. 2010; Dominik et al. 2012; Kremer et al. 2017), or the result of different star formation histories and Galactic spatial…”
On the α formalism for the common envelope interaction (2010, methodology): “Zorotovic et al. (2010) compared three α formalisms: the Yungelson et al. (1993) formalism, the Webbink (1984) formalism and a hybrid form between the two formalisms adopted by Hurley, Tout & Pols (2002).”
Supernova Type Ia progenitors from merging double white dwarfs - Using a new population synthesis model (2012, background): “Recently, Webbink (2008) and Zorotovic et al. (2010) claimed that the predictive power of theγ-scenario is more r stricted.”