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dc.contributor.authorMuñoz, Diego J.
dc.contributor.authorMiranda, Ryan
dc.contributor.authorLai, Dong
dc.date.accessioned2019-06-03T23:48:31Z
dc.date.available2019-06-03T23:48:31Z
dc.date.issued2019-01-20
dc.identifier.citationDiego J. Muñoz et al 2019 ApJ 871 84en_US
dc.identifier.issn1538-4357
dc.identifier.doi10.3847/1538-4357/aaf867
dc.identifier.urihttp://hdl.handle.net/10150/632469
dc.description.abstractWe carry out 2D viscous hydrodynamical simulations of circumbinary accretion using the moving-mesh code AREPO. We self-consistently compute the accretion flow over a wide range of spatial scales, from the circumbinary disk (CBD) far from the central binary, through accretion streamers, to the disks around individual binary components, resolving the flow down to 2% of the binary separation. We focus on equal-mass binaries with arbitrary eccentricities. We evolve the flow over long (viscous) timescales until a quasi-steady state is reached, in which the mass supply rate at large distances (M) over dot(0) (assumed constant) equals the time-averaged mass transfer rate across the disk and the total mass accretion rate onto the binary components. This quasi-steady state allows us to compute the secular angular momentum transfer rate onto the binary, <(J) over dot (b)>, and the resulting orbital evolution. Through direct computation of the gravitational and accretional torques on the binary, we find that <(J) over dot (b)> is consistently positive (i.e., the binary gains angular momentum), with l(0) equivalent to <(J) over dot (b)>/(M) over dot(0) in the range of (0.4 - 0.8) a(b)(2)Omega(b), depending on the binary eccentricity (where a(b), Omega(b) are the binary semimajor axis and angular frequency); we also find that this <(J) over dot (b)> is equal to the net angular momentum current across the CBD, indicating that global angular momentum balance is achieved in our simulations. In addition, we compute the time-averaged rate of change of the binary orbital energy for eccentric binaries and thus obtain the secular rates <(a) over dot (b)> and <(e) over dot (b)>. In all cases, <(a) over dot (b)> is positive; that is, the binary expands while accreting. We discuss the implications of our results for the merger of supermassive binary black holes and for the formation of close stellar binaries.en_US
dc.description.sponsorshipNSF [AST1715246]; NASA [NNX14AP31G]; Office of the Provost; Northwestern University Information Technologyen_US
dc.language.isoenen_US
dc.publisherIOP PUBLISHING LTDen_US
dc.relation.urlhttp://stacks.iop.org/0004-637X/871/i=1/a=84?key=crossref.48338f9c6e33da8e9bed34fdb76d0803en_US
dc.rights© 2019. The American Astronomical Society. All rights reserved.en_US
dc.subjectaccretion, accretion disksen_US
dc.subjectbinaries: generalen_US
dc.subjectblack hole physicsen_US
dc.subjectstars: pre-main sequenceen_US
dc.titleHydrodynamics of Circumbinary Accretion: Angular Momentum Transfer and Binary Orbital Evolutionen_US
dc.typeArticleen_US
dc.contributor.departmentUniv Arizona, Steward Observen_US
dc.identifier.journalASTROPHYSICAL JOURNALen_US
dc.description.collectioninformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.en_US
dc.eprint.versionFinal published versionen_US
dc.source.journaltitleThe Astrophysical Journal
dc.source.volume871
dc.source.issue1
dc.source.beginpage84
refterms.dateFOA2019-06-03T23:48:31Z


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