TY - JOUR
T1 - Binary Interaction Dominates Mass Ejection in Classical Novae
AU - Shen, Ken J.
AU - Quataert, Eliot
N1 - Funding Information:
We thank Laura Chomiuk, Dan Kasen, Brian Metzger, Raffaella Margutti, Alison Miller, Joe Patterson, Ondřej Pejcha, Brad Schaefer, and Jeno Sokoloski for helpful discussions, Bill Paxton and the MESA Council for developing MESA , and the referee for their thoughtful review. This work was supported by NASA through the Astrophysics Theory Program (80NSSC20K0544) and by the Research Corporation for Science Advancement through a “Scialog: Time Domain Astrophysics” award. 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 Berkeley Chancellor, Vice Chancellor of Research, and Office of the CIO).
Publisher Copyright:
© 2022. The Author(s). Published by the American Astronomical Society.
PY - 2022/10/1
Y1 - 2022/10/1
N2 - Recent observations suggest our understanding of mass loss in classical novae is incomplete, motivating a new theoretical examination of the physical processes responsible for nova mass ejection. In this paper, we perform hydrodynamical simulations of classical nova outflows using the stellar evolution code MESA. We find that, when the binary companion is neglected, white dwarfs with masses ≳0.8 M ⊙ successfully launch radiation-pressure-driven optically thick winds that carry away most of the envelope. However, for most of the mass-loss phase, these winds are accelerated at radii beyond the white dwarf's Roche radius assuming a typical cataclysmic variable donor. This means that, before a standard optically thick wind can be formed, mass loss will instead be initiated and shaped by binary interaction. An isotropic, optically thick wind is only successfully launched when the acceleration region recedes within the white dwarf's Roche radius, which occurs after most of the envelope has already been ejected. The interaction between these two modes of outflow - a first phase of slow, binary-driven, equatorially focused mass loss encompassing most of the mass ejection and a second phase consisting of a fast, isotropic, optically thick wind - is consistent with observations of aspherical ejecta and signatures of multiple outflow components. We also find that isolated lower-mass white dwarfs ≲ 0.8 M ⊙ do not develop unbound optically thick winds at any stage, making it even more crucial to consider the effects of the binary companion on the resulting outburst.
AB - Recent observations suggest our understanding of mass loss in classical novae is incomplete, motivating a new theoretical examination of the physical processes responsible for nova mass ejection. In this paper, we perform hydrodynamical simulations of classical nova outflows using the stellar evolution code MESA. We find that, when the binary companion is neglected, white dwarfs with masses ≳0.8 M ⊙ successfully launch radiation-pressure-driven optically thick winds that carry away most of the envelope. However, for most of the mass-loss phase, these winds are accelerated at radii beyond the white dwarf's Roche radius assuming a typical cataclysmic variable donor. This means that, before a standard optically thick wind can be formed, mass loss will instead be initiated and shaped by binary interaction. An isotropic, optically thick wind is only successfully launched when the acceleration region recedes within the white dwarf's Roche radius, which occurs after most of the envelope has already been ejected. The interaction between these two modes of outflow - a first phase of slow, binary-driven, equatorially focused mass loss encompassing most of the mass ejection and a second phase consisting of a fast, isotropic, optically thick wind - is consistent with observations of aspherical ejecta and signatures of multiple outflow components. We also find that isolated lower-mass white dwarfs ≲ 0.8 M ⊙ do not develop unbound optically thick winds at any stage, making it even more crucial to consider the effects of the binary companion on the resulting outburst.
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U2 - 10.3847/1538-4357/ac9136
DO - 10.3847/1538-4357/ac9136
M3 - Article
AN - SCOPUS:85145354251
SN - 0004-637X
VL - 938
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 1
M1 - 31
ER -