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Inertia-Centric Stability Analysis of a Planar Uniform Dust molecular cloud with Weak Neutral-Charged Dust Frictional Coupling

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Plasma Science and Technology 2014年第5期16卷 433-447页

作者： P.K.KARMAKAR B.BORAH Department of Physics Tezpur University

This paper adopts an inertia-centric evolutionary model to study the excitation mechanism of new gravito-electrostatic eigenmode structures in a one-dimensional（1-D） planar self-gravitating dust molecular cloud（DMC） on the Jeans scale.A quasi-neutral multi-fluid consisting of warm electrons,warm ions,neutral gas and identical inertial cold dust grains with partial ionization is *** grain-charge is assumed not to vary at the fluctuation evolution time *** neutral gas particles form the background,which is weakly coupled with the collapsing grainy plasma *** gravitational decoupling of the background neutral particles is justifiable for a higher inertial mass of the grains with higher neutral population density so that the Jeans mode frequency becomes reasonably *** physical basis is the Jeans assumption of a self-gravitating uniform medium adopted for fiducially analytical simplification by neglecting the zero-order ***,the equilibrium is justifiably treated initially as ＂homogeneous＂.The efficacious inertial role of the thermal species amidst weak collisions of the neutral-charged grains is taken into account.A standard multiscale technique over the gravito-electrostatic equilibrium yields a unique pair of Korteweg-de Vries（KdV） *** is integrated numerically by the fourth-order Runge-Kutta method with multi-parameter variation for exact shape ***,the model is conducive for the propagation of new conservative solitary spectral *** basic physics,parametric features and unique characteristics are *** results go qualitatively in good correspondence with the earlier observations made by *** applications relevant to space and astrophysical environments are concisely highlighted.

关键词： molecular cloud pair KdV equations solitary patterns

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Massive molecular cloud cores and activities of star formation

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Chinese Physics B 2005年第4期14卷 863-868页

作者：周武飞吴月芳魏悦巨秉刚 AstronomyDepartment PekingUniversityBeijing100871China QinghaiStation PurpleMountainObservatoryDeLingHa.817000China

We have mapped 23 sources in the J=1-0 lines of 12CO, 13CO and C18O with the 13.7-m telescope at Qinghai station of Purple Mountain Observatory. The samples were chosen from the massive star formation regions whose single point lines have the broad-wing profile. The mapping shows that 12 clouds have cores and 5 outflows were identified with the 12CO J=1-0 lines. Among the 12 cores, systematic velocity shifts were found in 2 cores, and blue asymmetric double-peak profile of 12CO line was found in IRAS 19529+2704, indicating that it may be an infall candidate. Physical parameters of the cores and outflows were derived from the local thermodynamic equilibrium assumption. The masses range from ～ 9.4 × 102M⊙ to ～ 2.2 × 105M⊙. The hydrogen molecule densities range from ～ 3.4 × 102cm-3 to～ 1.2 × 104cm-3. The molecular outflows have masses larger than 3.5M⊙, and kinetic energies greater than 0.9× *** outflows have significantly greater masses and kinetic energies than those from low-mass young stellar objects(YSOs). For the cores, 2MASS data are available, dozens of 2MASS sources with different colour indices and brightness are often found around IRAS source, among which the reddest 2MASS source is always within the IRAS error ellipse thus probably corresponds to the IRAS source.

关键词： Interstellar matter molecular cloud star formation

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Star Formation in Self-Gravitating molecular cloud: The Critical Mass and the Core Accretion Rate

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World Journal of Mechanics 2020年第5期10卷 53-67页

作者： Gemechu M. Kumssa S. B. Tessema Astronomy and Astrophysics Research Division Entoto Observatory and Research Center (EORC) Ethiopian Space Science and Technology Institute (ESSTI) Addis Ababa Ethiopia Addis Ababa University Addis Ababa Ethiopia Department of Physics College of Natural Sciences Jimma University Jimma Ethiopia

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.

关键词： Star Formation molecular cloud Critical Mass Core Accretion

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