Abstract Details
| Name: Prasun Dhang Affiliation: IISc Bangalore Conference ID: ASI2016_574 Title : Dichotomy between Black Hole and Neutron Star Accretion: Effect of Hard Surface Authors and Co-Authors : Co -Authors: 1. Prateek Sharma(IISc) 2. Banibrata Mukhopadhyay(IISc) Abstract Type : Poster Abstract Category : Stars, The Milky Way Galaxy and its neighbours Abstract : Estimates of accretion rate on to compact objects have been explored based on the well-known, spherically symmetric, inviscid, steady-state solution given by Bondi. This solution assumes that there is a sink of mass at the center - which in case of a black hole (BH) corresponds to the advection of matter across the event horizon. Other stars, such as a neutron star (NS), have surfaces and hence the infalling matter has to come to rest at the surface. We study the initial value problem in which the matter distribution is uniform and at rest at t=0 with two different inner radial boundary conditions: outflow boundary condition valid for a BH; and a reflective boundary condition for a NS. We obtain a similarity solution for the flow in the two cases (assuming a cold ambient medium) and compare with numerical simulations of the Euler equations. Numerical simulations show that spherical accretion on to NSs, and hence the energy released due to accretion, can be suppressed by orders of magnitude compared to BHs. These differences should be reflected in the observed luminosities of NS transient and BH transients when they are in quiescent states. |