TY - JOUR
T1 - The evolution and fate of super-Chandrasekhar mass white dwarf merger remnants
AU - Schwab, Josiah
AU - Quataert, Eliot
AU - Kasen, Daniel
N1 - Funding Information:
We thank Lars Bildsten, Jared Brooks, Rob Farmer, Jason Ferguson, Ken Shen, and Frank Timmes for helpful discussions.We thank Marius Dan and Cody Raskin for providing the results of their SPH simulations as part of previous work. We thank Ken'ichi Nomoto, Todd Thompson, and StanWoosley for useful conversations following the presentation of these results in preliminary form. We thank an anonymous referee for comments that led to improvements in the manuscript. We acknowledge stimulating workshops at Sky House and Palomar Observatory where these ideas germinated. JS is supported by the NSF Graduate Research Fellowship Program under grant DGE-1106400 and by NSF grant AST-1205732. EQ is supported in part by a Simons Investigator award from the Simons Foundation and the David and Lucile Packard Foundation. This research is funded in part by the Gordon and Betty Moore Foundation through Grant GBMF5076. DK was supported in part by a Department of Energy Office of Nuclear Physics Early Career Award, and by the Director, Office of Energy Research, Office of High Energy and Nuclear Physics, Divisions of Nuclear Physics, of the US Department of Energy under Contract no. DE-AC02-05CH11231. This research used the SAVIO computational cluster resource provided by the Berkeley Research Computing program at the University of California Berkeley (supported by the UC Chancellor, the UC Berkeley Vice Chancellor of Research, and the Office of the CIO). This research has made use of NASA's Astrophysics Data System and GNU Parallel (Tange 2011).
Funding Information:
We thank Lars Bildsten, Jared Brooks, Rob Farmer, Jason Fergu-son, Ken Shen, and Frank Timmes for helpful discussions. We thank Marius Dan and Cody Raskin for providing the results of their SPH simulations as part of previous work. We thank Ken’ichi Nomoto, Todd Thompson, and Stan Woosley for useful conversations following the presentation of these results in preliminary form. We thank an anonymous referee for comments that led to improvements in the manuscript. We acknowledge stimulating workshops at Sky House and Palomar Observatory where these ideas germinated. JS is supported by the NSF Graduate Research Fellowship Program under grant DGE-1106400 and by NSF grant AST-1205732. EQ is supported in part by a Simons Investigator award from the Si-mons Foundation and the David and Lucile Packard Foundation. This research is funded in part by the Gordon and Betty Moore Foundation through Grant GBMF5076. DK was supported in part by a Department of Energy Office of Nuclear Physics Early Career Award, and by the Director, Office of Energy Research, Office of High Energy and Nuclear Physics, Divisions of Nuclear Physics, of the US Department of Energy under Contract no. DE-AC02-05CH11231. This research used the SAVIO computational cluster resource provided by the Berkeley Research Computing program at the University of California Berkeley (supported by the UC Chancellor, the UC Berkeley Vice Chancellor of Research, and the Office of the CIO). This research has made use of NASA’s Astrophysics Data System and GNU Parallel (Tange 2011).
Publisher Copyright:
© 2017 The Authors.
PY - 2016/12/21
Y1 - 2016/12/21
N2 - We present stellar evolution calculations of the remnant of the merger of two carbon-oxygen white dwarfs (CO WDs). We focus on cases that have a total mass in excess of the Chandrasekhar mass. After the merger, the remnant manifests as an L ~ 3 × 104 L⊙ source for ~104 yr. A dusty wind may develop, leading these sources to be self-obscured and to appear similar to extreme asymptotic giant branch (AGB) stars. Roughly ~10 such objects should exist in the Milky Way and M31 at any time. As found in previous work, off-centre carbon fusion is ignited within the merger remnant and propagates inwards via a carbon flame, converting theWD to an oxygen-neon (ONe) composition. By following the evolution for longer than previous calculations, we demonstrate that after carbon-burning reaches the centre, neutrinocooledKelvin- Helmholtz contraction leads to off-centre neon ignition in remnantswith masses ≥ 1.35M⊙. The resulting neon-oxygen flame converts the core to a silicon WD. Thus, super- Chandrasekhar WD merger remnants do not undergo electron-capture induced collapse as traditionally assumed. Instead, if the remnant mass remains above the Chandrasekhar mass, we expect that it will form a low-mass iron core and collapse to form a neutron star. Remnants that lose sufficient mass will end up as massive, isolated ONe or Si WDs.
AB - We present stellar evolution calculations of the remnant of the merger of two carbon-oxygen white dwarfs (CO WDs). We focus on cases that have a total mass in excess of the Chandrasekhar mass. After the merger, the remnant manifests as an L ~ 3 × 104 L⊙ source for ~104 yr. A dusty wind may develop, leading these sources to be self-obscured and to appear similar to extreme asymptotic giant branch (AGB) stars. Roughly ~10 such objects should exist in the Milky Way and M31 at any time. As found in previous work, off-centre carbon fusion is ignited within the merger remnant and propagates inwards via a carbon flame, converting theWD to an oxygen-neon (ONe) composition. By following the evolution for longer than previous calculations, we demonstrate that after carbon-burning reaches the centre, neutrinocooledKelvin- Helmholtz contraction leads to off-centre neon ignition in remnantswith masses ≥ 1.35M⊙. The resulting neon-oxygen flame converts the core to a silicon WD. Thus, super- Chandrasekhar WD merger remnants do not undergo electron-capture induced collapse as traditionally assumed. Instead, if the remnant mass remains above the Chandrasekhar mass, we expect that it will form a low-mass iron core and collapse to form a neutron star. Remnants that lose sufficient mass will end up as massive, isolated ONe or Si WDs.
KW - Supernovae: general
KW - White dwarfs
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U2 - 10.1093/mnras/stw2249
DO - 10.1093/mnras/stw2249
M3 - Article
AN - SCOPUS:85018652584
SN - 0035-8711
VL - 463
SP - 3461
EP - 3475
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 4
ER -