The Sun Might Have Formed in a Small Star Cluster

Stars evolve in the universe in large groups, which astronomers call clusters, from clouds of gas. At the beginning of the universe a few seconds after the Big Bang, molecular hydrogen and helium formed the only known matter to exist. As different temperature variations and 'defects' in the structure of the huge cloud of gas that composed the universe started taking place, large parts of the gas cloud started spinning and collapsing under its own weight, creating stars and galaxies. Dying stars exploded into supernovas spreading new heavy elements, such as carbon, oxygen, iron, elements needed to form rocky planets like Earth.

Astronomers at Bonn, Germany, are now studying star formation inside clusters, and say that stars are almost but certain to always form in large groups. As well as stars, star clusters are created from interstellar gas and dust, inside which individual gas lumps collapse to make individual young stars, packed together in large regions of space, from a number of a few hundreds up to ten million stars, cramped into clusters, which might be as old as the universe.

Researches show that our own star, the Sun might have possibly formed in such a cluster which could have disintegrated as time passed, due to the weak gravitational field exerted by its components. Calculations also show that our solar system could not have formed in such a cluster, due to the gravitational influence of a star moving in the vicinity of the Sun, which it terms would prevent planet formation.

As star formation inside a cluster stops, the remnant gas between the individual stars would be swept away by electrically charged particles, allowing them to move freely, the same as those in the interstellar space of the Milky Way. It appears that heavy clusters are longer lived, clusters under a certain size being destroyed by radiation emitted by their own stars.

The Argelander Institute of Bonn conducting these researches recently received ultrafast "GRAPE Computers" to be used in critical star and star cluster simulations.