Lecture

Star Formation: Jeans Mass and Collapse

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In course

PHYS-209: Astrophysics I: introduction to astrophysics

Ce cours décrit de façon simple les processus physiques qui expliquent l'univers dans lequel nous vivons. En couvrant une large gamme de sujets, le but du cours est aussi de donner un aperçu général des objets astrophysiques qui nous entourent. ...

Description

This lecture covers the basics of star formation, focusing on the Jeans mass and collapse process in astrophysics. Starting with an introduction to astrophysics, the instructor explains how the radius and mass of Jeans play a crucial role in the collapse of star-forming regions. The free fall time, gravitational contraction, and energy conversion processes are also discussed in detail, highlighting the key factors that determine the formation of stars. The lecture concludes with a brief overview of nebulae and the star-forming region NGC 604.

In MOOC

Introduction to Astrophysics

How can we study the Universe we live in using the only available information it provides us with: light ? This course provides an overview of the physical phenomena at play in the astronomical objects surrounding us, from planets and stars to the cosmic filaments, from galaxies such as our own Milky Way to large galaxy clusters. The course emphasizes the links between theoretical predictions and observations. In this course, you will learn the basics of astrophysics using simplified mathematical developm

Official source

Quiz

Ontological neighbourhood

Astronomy

Astrophysics: Stellar astronomy

Related concepts (25)

Star formation

Star formation is the process by which dense regions within molecular clouds in interstellar space, sometimes referred to as "stellar nurseries" or "star-forming regions", collapse and form stars. As a branch of astronomy, star formation includes the study of the interstellar medium (ISM) and giant molecular clouds (GMC) as precursors to the star formation process, and the study of protostars and young stellar objects as its immediate products. It is closely related to planet formation, another branch of astronomy.

Nebula

A nebula ('cloud' or 'fog' in Latin; : nebulae, nebulæ or nebulas) is a distinct luminescent part of interstellar medium, which can consist of ionized, neutral, or molecular hydrogen and also cosmic dust. Nebulae are often star-forming regions, such as in the "Pillars of Creation" in the Eagle Nebula. In these regions, the formations of gas, dust, and other materials "clump" together to form denser regions, which attract further matter and eventually become dense enough to form stars.

Gravitational collapse

Gravitational collapse is the contraction of an astronomical object due to the influence of its own gravity, which tends to draw matter inward toward the center of gravity. Gravitational collapse is a fundamental mechanism for structure formation in the universe. Over time an initial, relatively smooth distribution of matter will collapse to form pockets of higher density, typically creating a hierarchy of condensed structures such as clusters of galaxies, stellar groups, stars and planets.

Planetary nebula

A planetary nebula (PN, plural PNe) is a type of emission nebula consisting of an expanding, glowing shell of ionized gas ejected from red giant stars late in their lives. The term "planetary nebula" is a misnomer because they are unrelated to planets. The term originates from the planet-like round shape of these nebulae observed by astronomers through early telescopes.

Jeans instability

In stellar physics, the Jeans instability causes the collapse of interstellar gas clouds and subsequent star formation, named after James Jeans. It occurs when the internal gas pressure is not strong enough to prevent gravitational collapse of a region filled with matter. For stability, the cloud must be in hydrostatic equilibrium, which in case of a spherical cloud translates to where is the enclosed mass, is the pressure, is the density of the gas (at radius ), is the gravitational constant, and is the radius.

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