Summary

Extract

This has been the first international conference devoted to hydrogen-deficient stars and related objects. As Professor Hunger stated in his introduction, one aim of a meeting such as this is to review our achievements and find out what conclusions we can reach about the nature and origin of the objects we study. However, it is even more important that we identity the questions that we must ask and particularly which questions it may be within our means to answer. A newspaper reporter is said to have asked the Chairman of our Local Organizing Committee what we proposed doing to correct this hydrogen deficiency!

Our meeting started with Drilling’s review of the galactic distributions and velocity dispersions of the various groups of hydrogen-deficient stars. They cover a wide range from the Population I rapidly rotating intermediate helium stars to the extreme helium stars and cool hydrogen-deficient stars, including the R Coronae Borealis (RCB) variables, which show characteristics of Intermediate Population II. We certainly need to be very clear how each of these classes is defined, particularly as there are a few objects, very definitely hydrogen-deficient, which fail to fit neatly into any of our categories. One star which has been the subject of three contributed papers and mentioned in others has too much hydrogen and too much gravity to be an extreme helium star, too little hydrogen to be an intermediate and too little gravity to be a subdwarf. I refer to BD+13°3224, otherwise known as V652 Her. As many of these stars are discovered to be variable they will be allotted variable star names. To avoid confusion it seems best to mention all known names.