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Main Authors: Shiber, Sagiv, De Marco, Orsola, Motl, Patrick M., Munson, Bradley, Marcello, Dominic C., Frank, Juhan, Diehl, Patrick, Clayton, Geoffrey C., Skinner, Bennett N., Kaiser, Hartmut, Daiss, Gregor, Pfluger, Dirk, Staff, Jan E.
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2404.06864
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author Shiber, Sagiv
De Marco, Orsola
Motl, Patrick M.
Munson, Bradley
Marcello, Dominic C.
Frank, Juhan
Diehl, Patrick
Clayton, Geoffrey C.
Skinner, Bennett N.
Kaiser, Hartmut
Daiss, Gregor
Pfluger, Dirk
Staff, Jan E.
author_facet Shiber, Sagiv
De Marco, Orsola
Motl, Patrick M.
Munson, Bradley
Marcello, Dominic C.
Frank, Juhan
Diehl, Patrick
Clayton, Geoffrey C.
Skinner, Bennett N.
Kaiser, Hartmut
Daiss, Gregor
Pfluger, Dirk
Staff, Jan E.
contents We study the properties of double white dwarf (DWD) mergers by performing hydrodynamic simulations using the new and improved adaptive mesh refinement code Octo-Tiger. We follow the orbital evolution of DWD systems of mass ratio q=0.7 for tens of orbits until and after the merger to investigate them as a possible origin for R Coronae Borealis (RCB) type stars. We reproduce previous results, finding that during the merger, the Helium WD donor star is tidally disrupted within 20-80 minutes since the beginning of the simulation onto the accretor Carbon-Oxygen WD, creating a high temperature shell around the accretor. We investigate the possible Helium burning in this shell and the merged object's general structure. Specifically, we are interested in the amount of Oxygen-16 dredged-up to the hot shell and the amount of Oxygen-18 produced. This is critical as the discovery of very low Oxygen-16 to Oxygen-18 ratios in RCB stars pointed out the merger scenario as a favorable explanation for their origin. A small amount of hydrogen in the donor may help keep the Oxygen-16 to Oxygen-18 ratios within observational bounds, even if moderate dredge-up from the accretor occurs. In addition, we perform a resolution study to reconcile the difference found in the amount of Oxygen-16 dredge-up between smoothed-particle hydrodynamics and grid-based simulations.
format Preprint
id arxiv_https___arxiv_org_abs_2404_06864
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Hydrodynamic simulations of WD-WD mergers and the origin of RCB stars
Shiber, Sagiv
De Marco, Orsola
Motl, Patrick M.
Munson, Bradley
Marcello, Dominic C.
Frank, Juhan
Diehl, Patrick
Clayton, Geoffrey C.
Skinner, Bennett N.
Kaiser, Hartmut
Daiss, Gregor
Pfluger, Dirk
Staff, Jan E.
Solar and Stellar Astrophysics
We study the properties of double white dwarf (DWD) mergers by performing hydrodynamic simulations using the new and improved adaptive mesh refinement code Octo-Tiger. We follow the orbital evolution of DWD systems of mass ratio q=0.7 for tens of orbits until and after the merger to investigate them as a possible origin for R Coronae Borealis (RCB) type stars. We reproduce previous results, finding that during the merger, the Helium WD donor star is tidally disrupted within 20-80 minutes since the beginning of the simulation onto the accretor Carbon-Oxygen WD, creating a high temperature shell around the accretor. We investigate the possible Helium burning in this shell and the merged object's general structure. Specifically, we are interested in the amount of Oxygen-16 dredged-up to the hot shell and the amount of Oxygen-18 produced. This is critical as the discovery of very low Oxygen-16 to Oxygen-18 ratios in RCB stars pointed out the merger scenario as a favorable explanation for their origin. A small amount of hydrogen in the donor may help keep the Oxygen-16 to Oxygen-18 ratios within observational bounds, even if moderate dredge-up from the accretor occurs. In addition, we perform a resolution study to reconcile the difference found in the amount of Oxygen-16 dredge-up between smoothed-particle hydrodynamics and grid-based simulations.
title Hydrodynamic simulations of WD-WD mergers and the origin of RCB stars
topic Solar and Stellar Astrophysics
url https://arxiv.org/abs/2404.06864