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Barnard 68
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Barnard 68

April 27, 2005
How do stars like our Sun come into being? Which fundamental processes are responsible for transforming a dark and diffuse interstellar cloud of gas and dust into a much denser, shining object?

Astronomers have just taken an important step towards answering this fundamental question. Based on the most detailed study ever made of the internal structure of a small interstellar cloud, three scientists from ESO and the USA [1] have found that it is apparently on the verge of becoming unstable - and thus in the stage immediately preceding a dramatic collapse into a dense and hot, low-mass star.

Interestingly, the current structure of this cloud, a "Bok globule" known as Barnard 68 (B68) [2], is governed by the same basic physics as is that of a star. The cloud is obviously in a temporary state of near-equilibrium, where the inward force of gravity caused by its mass more or less balances that of the outward pressure due to its temperature. But this situation may not last long.

The astronomers believe that this particular cloud, together with some others in the same galactic neighbourhood, constitute the few resistent remains of a much larger cloud that has disappeared due to the influence of strong stellar winds and ultraviolet radiation from young and heavy stars as well as supernova explosions.

The new and unique insight into the pre-collapse phase of the complicated process of stellar birth is based on observations made with ESO telescopes at the La Silla and Paranal observatories in Chile.