Does accretion cease when a star approaches breakup?

Abstract

view Abstract Citations (161) References (14) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Does Accretion Cease When a Star Approaches Breakup? Popham, Robert ; Narayan, Ramesh Abstract A steady-state thin accretion disk is modeled around a uniformly rotating unmagnetized star in order to investigate whether disk accretion can continue as the accreted angular momentum spins the central star to near breakup. A mapping between the specific angular momentum (SAM) added to the star and the stellar rotation rate (SRR) is obtained. When SRR is somewhat less than the breakup rotation rate of the star, a class of solutions is found where the angular velocity of the disk attains a maximum close to the star and then decreases rapidly in a boundary layer to match SRR. If SRR is near breakup, a second class of solutions is found where the disk angular velocity has no maximum but increases monotonically all the way down to the stellar surface. SAM decreases very rapidly with increasing SRR and even takes on fairly large negative values. The spin-up of an accreting star slows down and eventually stops at a rotation rate near breakup. Beyond this point, the star can continue to accrete any amount of matter without actually breaking up. Publication: The Astrophysical Journal Pub Date: April 1991 DOI: 10.1086/169847 Bibcode: 1991ApJ...370..604P Keywords: Accretion Disks; Binary Stars; Stellar Mass Accretion; Stellar Rotation; White Dwarf Stars; Angular Momentum; Boundary Conditions; Hydrodynamics; Numerical Analysis; Radial Velocity; Star Formation; Subsonic Flow; Supersonic Flow; Astrophysics; ACCRETION; STARS: ACCRETION; STARS: BINARIES; STARS: FORMATION; STARS: ROTATION; STARS: WHITE DWARFS full text sources ADS |