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How to Make a MegaStar

Big Bang


By Peter Barnes

Astronomers are still largely in the dark when it comes to understanding how the most massive stars form, but they are now pursuing several new strategies to solve this enduring mystery.

Peter Barnes is an Assistant Scientist in the Astronomy Department at the University of Florida.

The full text of this article can be purchased from Informit.

Galaxies are the building blocks of the universe. To understand how galaxies have evolved over cosmic time, you have to understand their overall ecology; that is, the global process of star birth from interstellar gas and dust, through stellar evolution and on to stellar death, when material enriched in heavy elements is returned to the interstellar medium and begins the cycle anew.

But the birth of most massive stars and star clusters, which dominate and define the beautiful spiral structure of disc galaxies, is still poorly understood. Without that understanding we may struggle to fully grasp the origin of smaller stars like the Sun, as well as the origin of the elements that enable life.

Low-Mass vs High-Mass Stars
Over the past two decades, astronomers have pieced together a fairly good idea of how low-mass stars (i.e. those with masses less than a few times the Sun’s mass) form. With numerous low-mass stellar nurseries accessible within a few hundred light years of the Sun, astronomers have been able to closely observe individual stars (or binaries) being born.

There are always more details to be figured out, of course, but the basic picture seems secure. It starts out with a very cold (only 8–10°K above absolute zero), very slowly-rotating cloud of gas and dust whose own internal gravity has, after many millions of years,...

The full text of this article can be purchased from Informit.