A Comprehensive Analysis of Stellar Systems

1 Introduction


Analysis of the data collected from various telescopes suggests that an interstellar cloud consisting of a star formation process system is one of the most violent environments systems ever discovered(Heathcote & Brand (1983)). The cloud consists of and guides the processes governing cycles of star formation processes. Based on the data collected from telescopes, the ISM cloud is very chaotic in nature wherein one single perturbation could provide a cyclic chain effect in the system leading to a series of events in the system( Bodifee & De Loore (1985). The aforementioned change in cloud structure can occur exponentially, resulting in either the system converging to a star-forming cycle or diverging, dampening the star-forming process and resulting in gaseous material dissipation in the Interstellar Medium.


The basic interaction of the structural components can be explained as to the trivial interactions between the three components of ISM- atomic, molecular, and stellar. The interactions mainly consist of conversion processes from one form to another in various cyclic phases. The nature and intensity of each of the interaction processes govern the long-term behavior of the system with the star-forming activity either being in-exhaustive in nature(Limit cycle) or dampening after some time(Stationary state)(Sharaf et al. (2012)). This suggests a stellar system is found to be very sensitive in nature with a high degree of dependence on initial conditions(Delgado-Donate et al. (2004)). Therefore, the existence of an equilibrium condition comes to be seen in the stellar structure where certain conditions must be satisfied to give rise to a star-forming structure(Das et al. (2020)). The equilibrium occurs when certain rates of intrinsic as well as extrinsic processes balance each other in a stable manner. This results in the generation of hydrostatic equilibrium in the body(Schaye (2004)).


2 Supernovae


2.1 Impact on the Interstellar Medium

When a given star of mass higher than 10 solar masses exhausts their fuel, they die releasing a supernovae remnant wave through the ISM. The remnant mainly consists of two components- ionizing radiation and kinetic energy of ejected material. The passing shockwave remnant when it interacts with the interstellar gas through both of its components. Hydrodynamical simulation performed by authors such as Klein et al. (2003) estimated the total released ionized energy to be a fraction amount of the total amount of the energy in ISM through ejecta material(1051 erges). The medium surrounding the star system is a heterogeneous structure consisting of varying quantities of multiple types of gases. The system also exhibits the characteristics of an open system with an open reservoir which continuously supplies the system with an unlimited supply of gas from the interstellar environment(Bodifee & De Loore (1985), Bodifee (1986)).


The gas components display a certain degree of randomness in the ISM where they are distributed in a disordered manner throughout the structure. When the shockwave interacts with the ISM, perturbing the individual state of components and transferring the momentum to the body( Klein et al. (2003)). The velocity of the shockwave decelerates, achieving a constant speed, then the shockwave accelerates again when it leaves the cloud structure(Al¯uzas et al. (2012)). This results in the generation of some local fluctuations in the body(Bodifee & De Loore (1985))


Al¯uzas et al. (2012) performed hydrodynamic simulations of shockwaves interacting with many individual clouds. When the intensity of the shockwave was varied, it showed that the density of the gas medium reduced the intensity of the shockwave by a particular fraction. The latter leads to the formation of dense shells within the structure. These local fluctuations are later distributed throughout the system with time resulting in a cyclic phase of changes in the system.


2.2 Star formation triggering

Due to interaction with supernovae shockwave, the perturbed cloud consists of local density fluctuations which have manifested themselves into the interstellar medium (Bodifee & De Loore (1985), Elmegreen (1993), Sharaf et al. (2012)). Due to the randomness of gas molecules, the local density fluctuations are now amplified non-linearly in the system through a positive feedback mechanism. The variable rate of momentum transferred to the stellar body depends crucially on the density and nature of the interstellar gas and shockwave.


Using a 3-D magnetohydrodynamic simulation, Sarson et al. (2004) performed numerical simulations of multiple phases of ISM and self-regulating system structure releasing periodic in the presence of periodic supernovae shock2 waves. The study showed a numerical power-law relation existing between the star-forming rate and density. Therefore, the more the density of interstellar clouds the greater would be the rate of star formation after perturbation of cloud with supernovae shockwave. Spitzer Jr (1982) analyzed the effect of variable intensity of the shockwave on the system and showed that when the intensity of shockwave was above 2.76, 4 percent of the shockwave deflected away from the cloud as an acoustic wave which further increased the temperature of neutral cloud region.


References


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Das, S., Chattopadhyay, T., & Mukherjee, S. 2020, Monthly Notices of the Royal Astronomical Society, 494, 4098


Delgado-Donate, E., Clarke, C., & Bate, M. 2004, Monthly Notices of the Royal Astronomical Society, 347, 759


Elmegreen, B. G. 1993, in Protostars and Planets III, 97–124


Heathcote, S., & Brand, P. 1983, Monthly Notices of the Royal Astronomical Society, 203, 67


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