Lecture

Stellar Formations: Jeans Mass and Radius

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Description

This lecture covers the formation of stars, starting with the Virial theorem and the Jeans Mass and Radius, which determine the conditions for gravitational collapse. It then explores the Free-fall Time and Gravitational Contraction, discussing the total energy and the life time of stars through fusion processes.

In MOOC

The Radio Sky I: Science and Observations

The serendipitous and unexpected discovery of radio emission from celestial objects opened up the possibility of studying a new and exciting view of the universe beyond the visible spectrum. Astronomers have been studying the cosmos in visible light since ancient Greece, but it is only in comparatively modern times that the universe beyond the visible spectrum has become accessible to us. In this course you will learn about the most important objects that emit in the radio regime, both within and beyond ou

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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.

Stellar evolution

Stellar evolution is the process by which a star changes over the course of time. Depending on the mass of the star, its lifetime can range from a few million years for the most massive to trillions of years for the least massive, which is considerably longer than the current age of the universe. The table shows the lifetimes of stars as a function of their masses. All stars are formed from collapsing clouds of gas and dust, often called nebulae or molecular clouds.

Stellar dynamics

Stellar dynamics is the branch of astrophysics which describes in a statistical way the collective motions of stars subject to their mutual gravity. The essential difference from celestial mechanics is that the number of body Typical galaxies have upwards of millions of macroscopic gravitating bodies and countless number of neutrinos and perhaps other dark microscopic bodies. Also each star contributes more or less equally to the total gravitational field, whereas in celestial mechanics the pull of a massive body dominates any satellite orbits.

Galaxy formation and evolution

The study of galaxy formation and evolution is concerned with the processes that formed a heterogeneous universe from a homogeneous beginning, the formation of the first galaxies, the way galaxies change over time, and the processes that have generated the variety of structures observed in nearby galaxies. Galaxy formation is hypothesized to occur from structure formation theories, as a result of tiny quantum fluctuations in the aftermath of the Big Bang.

Stellar black hole

A stellar black hole (or stellar-mass black hole) is a black hole formed by the gravitational collapse of a star. They have masses ranging from about 5 to several tens of solar masses. The process is observed as a hypernova explosion or as a gamma ray burst. These black holes are also referred to as collapsars. By the no-hair theorem, a black hole can only have three fundamental properties: mass, electric charge, and angular momentum. The angular momentum of a stellar black hole is due to the conservation of angular momentum of the star or objects that produced it.

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