Understanding how stars form in molecular clouds is one of the ongoing research areas in astrophysics. Star formation is the fundamental process to which our current understanding remains incomplete due to the complex...Understanding how stars form in molecular clouds is one of the ongoing research areas in astrophysics. Star formation is the fundamental process to which our current understanding remains incomplete due to the complexity of the physics that drives their formation within molecular clouds. In this article theoretical modelling of the lowest possible mass of the cloud needed for collapse and the core accretion rate has been presented for the molecular cloud collapsing under its gravity. In many of previous studies the critical mass of star forming cloud under its gravity has been modelled using kinetic energy and gravitational potential energy. However, we test the effect of thermodynamic efficiency factor together with other physical processes in describing the critical mass, and controlling or triggering the rate of mass falling onto the central core. Assuming that, the ratio of radiation luminosity to gravitational energy released per unit time of the collapsing MC is less than unity. Following this conceptual framework we have formulated the critical mass and the core accretion rate of the self-gravitating molecular cloud.展开更多
The magnitude of the inner edge of accretion disks in low mass X-ray binaries is controversial in theoretical considerations and observations. Using the inner boundary conditions of accretion disks the inner disk radi...The magnitude of the inner edge of accretion disks in low mass X-ray binaries is controversial in theoretical considerations and observations. Using the inner boundary conditions of accretion disks the inner disk radius has been calculated by taking into account the effect of feedback radiation and the deviation of disk rotation from Keplerian. Results have been applied to the observations and possible interpretations have been proposed for the X-ray spectra and quasiperiodic oscillations.展开更多
We formulate and solve the problem of spherically symmetric, steady state, adiabatic accretion onto a Schwarzschild-like black hole obtained recently. We derive the general analytic expressions for the critical points...We formulate and solve the problem of spherically symmetric, steady state, adiabatic accretion onto a Schwarzschild-like black hole obtained recently. We derive the general analytic expressions for the critical points, the critical velocity, the critical speed of sound, and subsequently the mass accretion rate. The case for polytropic gas is discussed in detail. We find the parameter characterizing the breaking of Lorentz symmetry will slow down the mass accretion rate, while has no effect on the gas compression and the temperature profile below the critical radius and at the event horizon.展开更多
文摘Understanding how stars form in molecular clouds is one of the ongoing research areas in astrophysics. Star formation is the fundamental process to which our current understanding remains incomplete due to the complexity of the physics that drives their formation within molecular clouds. In this article theoretical modelling of the lowest possible mass of the cloud needed for collapse and the core accretion rate has been presented for the molecular cloud collapsing under its gravity. In many of previous studies the critical mass of star forming cloud under its gravity has been modelled using kinetic energy and gravitational potential energy. However, we test the effect of thermodynamic efficiency factor together with other physical processes in describing the critical mass, and controlling or triggering the rate of mass falling onto the central core. Assuming that, the ratio of radiation luminosity to gravitational energy released per unit time of the collapsing MC is less than unity. Following this conceptual framework we have formulated the critical mass and the core accretion rate of the self-gravitating molecular cloud.
基金National Natural Science Foundation of the People’s Republic of China“The thermal evolution and X-ray bursts in accreting strange stars”(12263006)“A combining study of the theoretical simulations and observations about the structure and evolution of magnetic massive stars and related objects”(U2031204)Natural Science Foundation of Xinjiang“The study of crust cooling of soft X-ray transients”(2020D01C063).
基金the National Natural Science Foundation of China and Ph.D. Research Funds
文摘The magnitude of the inner edge of accretion disks in low mass X-ray binaries is controversial in theoretical considerations and observations. Using the inner boundary conditions of accretion disks the inner disk radius has been calculated by taking into account the effect of feedback radiation and the deviation of disk rotation from Keplerian. Results have been applied to the observations and possible interpretations have been proposed for the X-ray spectra and quasiperiodic oscillations.
基金Supported by National Natural Science Foundation of China under Grant No.11273010the Hebei Provincial Outstanding Youth Fund under Grant No.A2014201068+1 种基金the Outstanding Youth Fund of Hebei University under Grant No.2012JQ02the Midwest Universities Comprehensive Strength Promotion Project
文摘We formulate and solve the problem of spherically symmetric, steady state, adiabatic accretion onto a Schwarzschild-like black hole obtained recently. We derive the general analytic expressions for the critical points, the critical velocity, the critical speed of sound, and subsequently the mass accretion rate. The case for polytropic gas is discussed in detail. We find the parameter characterizing the breaking of Lorentz symmetry will slow down the mass accretion rate, while has no effect on the gas compression and the temperature profile below the critical radius and at the event horizon.
