Advection-dominated accretion: A self-similar solution

TLDR

Viscous rotating accretion flows can store most dissipated energy as entropy rather than radiating it, and such advection‑dominated flows arise when the optical depth is very small or very large. The authors propose that advection‑dominated accretion explains the slow spin rates of accreting stars and the common occurrence of outflows and jets. They derive a family of self‑similar solutions with nearly virial temperature and quasi‑spherical geometry. The solutions show sub‑Keplerian rotation, a positive Bernoulli parameter indicating potential outflows, and convection that amplifies these effects. Published in ApJ 1994 (DOI 10.1086/187381, arXiv astro‑ph/9403052).

Abstract

view Abstract Citations (1959) References (13) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Advection-dominated Accretion: A Self-similar Solution Narayan, Ramesh ; Yi, Insu Abstract We consider viscous rotating accretion flows in which most of the viscously dissipated energy is stored as entropy rather than being radiated. Such advection-dominated flows may occur when the optical depth is either very small or very large. We obtain a family of self-similar solutions where the temperature of the accreting gas is nearly virial and the flow is quasi-spherical. The gas rotates at much less than the Keplerian angular velocity; therefore, the central stars in such flows will cease to spin up long before they reach the break-up limit. Further, the Bernoulli parameter is positive, implying that advection-dominated flows are susceptible to producing outflows. Convection is likely in many of these flows and, if present, will tend to enhance the above effects. We suggest that advection-dominated accretion may provide an explanation for the slow spin rates of accreting stars and the widespread occurrence of outflows and jets in accreting systems. Publication: The Astrophysical Journal Pub Date: June 1994 DOI: 10.1086/187381 arXiv: arXiv:astro-ph/9403052 Bibcode: 1994ApJ...428L..13N Keywords: Accretion Disks; Advection; Astronomical Models; Black Holes (Astronomy); Cooling Flows (Astrophysics); Stellar Mass Accretion; Viscous Flow; Hydrodynamics; Rotating Disks; Two Dimensional Flow; Astrophysics; ACCRETION; ACCRETION DISKS; BLACK HOLE PHYSICS; HYDRODYNAMICS; Astrophysics E-Print: 7 pages of text, 1 postscript figure, plain TeX, Harvard-Smithsonian Center for Astrophysics Preprint Series No. 3809 full text sources arXiv | ADS |