Bøger af Jean-Pierre Swings

The XIXth General Assembly of the International Astronomical Union was held in New Delhi, India, from November 19 to 28, 1985. It was dedicated to the memory of a former IAU President, Professor M. K. V. Bappu, who tragically passed away on August 19, 1982. On the occasion of the Delhi General Assembly, the IAU Minor Planet Center announced that Minor Planet (asteroid) No. 2596 henceforth will carry the name Vainu Sappu. The full text of the announcement reads: "e;(2596) VAINU BAPPU = 1979 KN (diameter about 8 kilometers, period 5 years 4 months, mean distance from the Sun around 450 million kilometers) Discovered 1979, May 19, by R. M. West at the European Southern Observatory. Named in memory of Manali f

Ken Freeman I would like to pick out a few items that I found particularly interesting. The choice probably reflects my ignorance, because many of these topics are no doubt more known to most of you. I am fairly sure that some of them are basic and important. We will start with the first session. There were three closely related papers on the evolution of massive stars, the formation of open clusters and associations and the IMF. We learned that clusters appear to form in initially bound clouds 6 of masses between 10'+_10 M , but star formation is a destructive process. Most of the gas is@ lost and the remaining stars then find themselves in an unbound system, which naturally disperses on a dynamical time. As a result of this, star formation is typically a fairly inefficient process, at least on the scale of open clusters. However (as Heggie pointed out) it seems to be somewhat more efficient on smaller scales, as evidenced by the fairly high incidence of binary stars. To form a bound cluster requires a higher efficiency of star formation, typically 30% or more, and we see how the three papers of this morning session relate: the initial mass function and the timing of where and when the DB stars form dictate the likely fate of the system.

Ken Freeman I would like to pick out a few items that I found particularly interesting. The choice probably reflects my ignorance, because many of these topics are no doubt more known to most of you. I am fairly sure that some of them are basic and important. We will start with the first session. There were three closely related papers on the evolution of massive stars, the formation of open clusters and associations and the IMF. We learned that clusters appear to form in initially bound clouds 6 of masses between 10'+_10 M , but star formation is a destructive process. Most of the gas is@ lost and the remaining stars then find themselves in an unbound system, which naturally disperses on a dynamical time. As a result of this, star formation is typically a fairly inefficient process, at least on the scale of open clusters. However (as Heggie pointed out) it seems to be somewhat more efficient on smaller scales, as evidenced by the fairly high incidence of binary stars. To form a bound cluster requires a higher efficiency of star formation, typically 30% or more, and we see how the three papers of this morning session relate: the initial mass function and the timing of where and when the DB stars form dictate the likely fate of the system.