This issue of ILBA will be "practical" - it will contain several announcements which you will (hopefully) consider as useful.
The proceedings of our meeting held in September of last year in Belogradchik are nearly finished and published.To be precise, they are already avaliable on the web at the following address: http://libra.astro.bas.bg/~aobel/bmya2000/proceedings.html.
According to news from the beginning of July, the book and the CD will be distributed in a short time.
The editors are aware of two forthcoming meetings devoted to space science in the Balkan countries:The Hellenic Astronomical Society will hold its fifth meeting in Heraklion on the island of Crete. According to news avaliable on the web (http://astrophysics.physics.uoc.gr/conf/) the preliminary scientific program is already known. Taking into account the program, and the natural and archeological beauties of the island, this will certainly be a successfull meeting.
In one of the previous issues of ILBA, we have announced the Odessa Summer School. Preparations are well underway, and (at least in Yugoslavia), this school has arisen considerable interest. At the end of July, a group of more than 20 students of astronomy and amateur astronomers from Serbia is planning to make a collective trip to Odessa.
For those interested in solar physics, a promissing meeting has just been announced a few days ago. It is the 10th European Solar Physics Meeting,to be held in Prague in the Czech Republic in September of next year. Details are avaliable at http://www.asu.cas.cz/~spm10/
This section contains a list of new publications by authors from the Balkan contries. It is certainly not complete, but this is a direct consequence of your letters to the editors of ILBA. If you find that some of your publications are not included, please send the references to the editors, and we shall be glad to include them in a forthcoming issue.
constant and the fate of the DDM theory
Temporis Acti, or Why Cosmology is Alive and Well
- A Reply
Is the Universe
Really So Simple?
oscillations in the early Universe
effect on neutrino oscillations and primordial He-4
redshift-space two-point correlation functions of galaxies and
groups in the Nearby Optical Galaxy sample
Activity Study of
Single G and K Giants
Thesis work conducted
at: Institute of
Institute of Astronomy,
Ph. D degree awarded: May 2001
The magnetic activity in single late giants is a poorly studied problem. The reasons for magnetic activity in such evolved stars are still not clear. The aim of my research was to verify the existing hypotheses for magnetic activity in these stars and also to study their activity properties. 14 single giants with theoretical or observational evidences for activity - faster rotation, high Li abundance, CaII K&H emission cores, photometric variability due to spots, detected flares and other activity indicators, were selected.
CaII K&H and Halpha spectral study and UBV photometric measurements and patrol monitoring were carried out for these stars. Their evolutionary status was also studied. A determination of their situation in the H-R diagram was done on the basis of Hipparcos parallaxes. For more detail study of their evolutionary stage chemical abundances analysis was also carried out.
Nevertheless one should expect all these stars to be active, the study revealed that only 4 of them have evidences for activity and one more was suspected in activity. These are OP And, V390 Aur, HD112989 and HD145001. HD121107 was suspected in activity.
The evolutionary status study found OP And and V390 Aur to be small-mass fairly evolved giants, while the rest 3 stars appeared intermediate-mass giants at different evolutionary stages. A difference in the activity level and behavior between low and intermediate mass single giants I studied was found - the last ones exhibited weaker activity properties.
The small number active single giants and their evolutionary status rise again the question about the conditions for dynamo action in these stars. In addition, the Li--rich single giants we studied exhibited no evidences for activity, nevertheless they have the same evolutionary stage like the known small-mass active single giants and, according to the theory the conditions in their convective envelopes should be similar. The absence of activity in the faster rotating well-mixed giant HD185958 also is in contradiction with the theoretical predictions. It seems, not every single giant become active and additional factors should play role for the activity and faster rotation in these stars.
Acknowledgements: I would like to thank all colleagues in Bulgaria and abroad who helped me with useful advices and discussions. Special thanks I express to Prof. J.R. De Medeiros for directing my attention to the intermediate-mass faster rotating single giants.
Dedication: The results of my PhD work are dedicated to the memory of my father, my uncle and to Prof. Vladimir Dermendjiev -- an excellent astronomer and friend who left us few months ago. Their selfless work has always been an example for me.
To all readers of ILBA the editors wish happy and agreable holidays, professional sucesses and (of course) all the possible personal luck. At the end we repeat our old demand: if you find ILBA useful and interesting, inform us about your work that is the only way to make it better, and to disseminate information on Balkan Astronomy.