ISO leads our eyes to young and small star
1 December 1998Why are some stars 'born' with only 10% of the mass of our Sun while at the other extreme, some may have 50 times as much material.
This question is important since the main factor that dictates the life cycle of a star is its initial mass. Stars seem to range in mass from 0.08 solar masses to about 100 solar masses (one solar mass is simply the mass of our Sun). One of the major challenges in present-day astrophysics is to explain this range of masses and in particular the numbers of stars created with different masses -for example, why are there a lot more young stars with low mass than with high mass. The equation that tells us how many stars there are at each different mass is known to astronomers as Initial Mass Function.
Star clusters, especially young ones, provide an excellent 'cosmic laboratory' for studying this problem, since stars in a cluster have the same age, composition and are at the same distance from us.
One of the difficulties, though, in studying such clusters is that they tend to be embedded in clouds of dust and are therefore difficult to observe by 'traditional' means. This is where new techniques, such as those offered by infrared astronomy, come into play. Infrared wavelengths offer the opportunity to see into such clouds. ESA's Infrared Space Observatory (ISO) with its infrared camera (ISOCAM) has proved an excellent facility for tackling this problem.
manda Kaas of the Stockholm Observatory will give an Internal Seminar at ESTEC, entitled "ISO Leads our Eyes to the Young and Small Star" describing the most recent work in this area and how it is effecting our understanding of the Initial Mass Function.