New Stars Are Born

A star is born, but this time we are not speaking of Judy Garland in A Star is Born but of what scientists call a star forming region that exists because a giant cloud of gas and dust collapsed releasing materials that can regroup and ... form stars. The specific area is within the Milky Way Galaxy, our home galaxy, and is called rather poetically NGC 3603.

Lead researcher Wolfgang Brandner and his team wanted to measure the motion of the stars within cluster NGC 3603 in order to confirm star formation theory and predict future movement within the star cluster. Their measurements, taken in a new and imaginative way, showed that the new star movement within the cluster is contrary to expectations and not in keeping with current theory of how stars within young star clusters develop, or evolve if you will.

After two years of painstaking analysis of two sets of images from Hubble telescope, the team, including then Ph.D. candidate Boyke Rochau, discovered a discrepancy between the predicted star movement and the actual star movement. Stars move and are expected to move in relation to their mass: stars' velocity correlates in a direct relationship to their mass. The stars in cluster NGC 3603, however, do not move in relation to their masses. On the contrary, they move independently of their masses.

More than 700 stars having different masses and surface temperatures within the cluster were measured from two sets of images. The first set of images was taken by Hubble telescope in July 1997. The second set of images was taken by Hubble in September 2007 producing two sets of images ten years apart. Hubble was programed to take the 2007 images from the same camera, the Wide Field Camera, and with the same filters as the 1997 images were taken with. Analysis of minute measurements followed.

Two years of measurement and analysis yielded the surprising result stated above, that the new stars in the young star cluster move independently of their mass. The inference that Brandner and Rochau draw from this is that conditions within NGC 3603 continue to reflect conditions present from the time the cluster was formed. The formation of NGC 3603 was approximately one million years ago. The expectation was that after one million years, Newtonian physics would govern velocity so that velocity would be dependent on mass, but Brandner's team has shown that this surprisingly is not the case.