Monthly Archives: October 2015

A star is born (Part 3 cont.: Evidence of a protostar in a Bok globule)

Bok globules are small interstellar clouds of very cold gas and dust that are nearly totally opaque to visible light as we’ve already seen in a previous post. Although they can be studied with infrared and radio techniques. They were … Continue reading

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A star is born (Part 3: The Virial Theorem, Jeans mass and Bok globules)

In this article I will try to show by skipping calculations and focus on the process on how to get to the result, that from a theorem called the Virial theorem, given a molecular cloud composition (mostly hydrogen), known density … Continue reading

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How bright is a star? Introducing apparent and absolute magnitude

In ancient Greece, for approx 2000 years ago, the Greek astronomer Hipparchus was the first to make a catalog of stars according to their brightness. The brightest stars were ‘magnitude 1’, the next brightest were ‘magnitude 2’, etc., down to … Continue reading

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