Senior researchers of Abastumani Astrophysical Observatory have won the projects for basic research 2016:
Rieger-type periodicity in solar activity and seismology of solar interior
Solar activity, which basically determines the conditions of interplanetary space and has tremendous influence on the Earth, is not yet completely understood. It has a main period of about 11 years, which is supposed to be governed by large-scale magnetic dynamo action in the interior. However, the activity also undergoes temporal variations of shorter time scales of 155-160 days, which is usually referred as Rieger-type periodicity. The periodicity has enigmatic character as it appears only in certain solar cycles and its physical basis is not known. Recent analysis revealed, however, that the periods are correlated with solar cycle strength; hence they could be connected with the dynamo layer in the solar interior, where the dynamo magnetic field is amplified.
This project aims to perform comprehensive analysis of different existing solar data sources (sunspot areas, sunspot numbers, radio flux, total irradiance, coronal mass ejections, solar flares) with different statistical methods (Fourier, wavelet, empirical mode decomposition) in order to find statistically significant periods in each individual solar cycle. The periodicity will be theoretically modeled by magnetic Rossby waves in the dynamo layer. The dispersion relation of the waves depends on the strength of toroidal magnetic field, therefore observed periods and theoretical spectrum of magnetic Rossby waves will be used to probe the dynamo layer during individual cycles. The estimated magnetic field strength may appear as a clue to test physical basis for different dynamo models. Therefore, expected results of the project will have tremendous importance for understanding solar activity and related phenomena.
Principal Investigator: Teimuraz Zaqarashvili
Project Coordinator: Vasil Kukhianidze
Consultant: Ramon Oliver
Key personnel: Tamar Gachechiladze, Zurab Vashalomidze, Eka Gurgenashvili
The Next Possible Outburst of P Cygni
On the basis of unpublished long-duration UBV observations of P Cygni (Abastumani Observatory, 1937-1983), it is clear that the star has undergone reddening. P cygni is a Luminous Blue Variable (LBV) and a supernova impostor. The star’s B-V color has values between -0.4 (1950-ies) and -0.1 (1980-ies) after correcting for the interstellar reddening. It means that the star probably had earlier spectral type for the beginning of 20-th century and we are witnessing of its evolutionary changes. On the HR diagram the star moves gradually to the instability strip of “constant temperature outburst phase”. If the rate of P Cygni’s reddening will be the same, then the star will have the next eruption (or even supernova explosion) after approximately 100 years.
According to the behavior of UBV light curves, we suggest that P Cygni could pulsate. Hypothesis of binarity of the star is also valid.
We began UBVRI photometric observations of P Cygni in the Abastumani from 2014 and the star continues to redden. Spectral observations are underway in Shamakhy Observatory, Azerbaijan.
We are planning to test our assumptions using model calculations, for which we invited the German consultant, the well-known expert in this field.
Any of the observational data are significant for specification of model parameters.The star itself maybe a “Rosetta Stone” for investigation of nature and evolution of massive stars generally and in particular for the LBVs.
Two experienced astronomers and three young scientists – PhD, MA and PhD student are in key personnel of the project.
Principal Investigator: Nino Kochiashvili
Project Coordinator: Sopia Beradze
Consultant: Wolf-Rainer Hamann
Key personnel: Rezo Natsvlishvili, Ia Kochiashvili, Manana vardosanidze
The Solar Coronal Holes and their connection to Solar Low Atmospheric Magnetic Structures
During fundamental processes occurred on Sun great amount of energy radiates to space. Detail research of solar energy transportation through Solar System remains a serious problm to modern science. In this contest it is important to study of relationship of coronal holes, background magnetic fields and centers of solar activities regarding of their evolution. The goal of this project is to study of these structures as a part of common processes.
One of the most actual problems is study of tree-dimensional structures of coronal holes.
To achieve this goal we are going to complete following three objectives:
1. Study of cinematic and dynamic characteristics of coronal holes with correlation of solar activity cycle;
2. Measurements of changes in coronal holes areas and different layers of heliosphere from photosphere to corona (including);
3. Establishment of relationship between coronal holes and background magnetic fields structures.
Within this project we will be using quasi-simultaneous observations materials on different layers of heliosphere from photosphere to corona (including) received at multiple solar telescopes of Abastumany astrophysical observatory. In addition, we will be searching observation materials of space telescopes and other observatories in internet.
Results of our study will be published in international referred scientific journals. Planned events will let us take part in international conferences and seminars.
Principal Investigator: Natela Ograpishvili
Project Coordinator: Davit Maghradze
Consultant: Nataly Stepanian
Key personnel: Natela Ograpishvili, Davit Maghradze, Tamar Gachechiladze