New stars' H-alpha emissions help scientists with their counting

Oct 2, 2008 13:53 GMT  ·  By

Since the distance between space's bodies is so enormous, astronomers have very hard times counting and measuring all the newly-emerging stars. That's why the H-alpha characteristic signal emitted by the new stars comes as a blessing for those who detect them by telescope. The amount of such rays emitted from a certain portion of the sky is in direct proportion to the number of such star birth events.

But the H-alpha radiation only emits from the neighborhood of heavy stars, whose relation to the lighter ones, as previously believed, is 1 to every 230. This means that there is a certain specific ratio of formation for these 2 star weight categories, as for 230 lightweight stars, a massive, heavy one is born. Yet, a recent study led by scientists from the Bonn University in Germany proved that this ratio is only valid for the galactic cores, where star cluster concentration is far denser. Still, although “H-alpha babies”, as massive stars are called, are not present in the outer regions of the galaxy, this doesn't rule out the fact that there are still stars forming there, which need to be taken into consideration as they influence the count.

Previous findings indicated that the H-alpha rays stopped all of a sudden at the edges of Milky Way-like disk-shaped galaxies. “The explanation offered is simply that too little gaseous matter exists for it to collapse into balls and form stars,” stated Jan Pflamm-Altenburg from Bonn University's Argelander Institute of Astronomy. But the recent satellite observations proved that light stars are constantly forming in those areas as well, only that, with no exception, they're too light in order to emanate H-alpha radiations. Anyway, they still affect the 230 to 1 star birth ratio, which should now be recalculated. In fact, the experts from Bonn University estimate that each H-alpha baby located closer to the edge of the galaxies is virtually accompanied by about a thousand of lighter counterparts. This theory comes to confirm the claims according to which new stars' masses are directly dependent on gas amounts and masses in their proximity.