19 بهمن 1401
محسن نژاد اصغر

محسن نژاد اصغر

مرتبه علمی: دانشیار
نشانی: گروه فیزیک دانشگاه مازندران
تحصیلات: دکترای تخصصی / فیزیک
تلفن: 09355892196
دانشکده: دانشکده علوم پایه

مشخصات پژوهش

عنوان Occurrence of instability through the protostellar accretion disks by landing of low-mass condensations
نوع پژوهش مقاله چاپ شده
کلیدواژه‌ها
Accretion disks --Instabilities -- Planets and satellites: formation
مجله ASTROPHYSICS AND SPACE SCIENCE
شناسه DOI
پژوهشگران محجوبه الیاسی (نفر اول) ، محسن نژاد اصغر (نفر دوم)

چکیده

Low-mass condensations (LMCs) are observed inside the envelope of the collapsing molecular cloud cores. In this research, we investigate the effects of landing LMCs for occurrence of instability through the protostellar accretion disks. We consider some regions of the disk where duration of infalling and landing of the LMCs are shorter than the orbital period. In this way, we can consider the landing LMCs as density bumps and grooves in the azimuthal direction of an initial thin axisymmetric steady state self-gravitating protostellar accretion disk (nearly Keplerian). Using the linear effects of the bump quantities, we obtain a characteristic equation for growth/decay rate of bumps; we numerically solve it to find occurrence of instability. We also evaluate the minimum-growth-time-scale (MGTS) and the enhanced mass accretion rate. The results show that infalling and landing of the LMCs in the inner regions of the protostellar accretion disks can cause faster unstable modes and less enhanced accretion rates relative to the outer regions. Also, more fragmentation of landed LMCs in the azimuthal direction have less chance for instability, and then can produce more values of enhanced mass accretion rate.