Pravidelné semináře pořádáme jednou měsíčně (říjen–červen, zpravidla první pondělí v měsíci) od 13 hod v seminární místnosti pracoviště Ondřejov. (archiv seminářů)
02. 04. 2012
Fundamental magnetic field properties of sunspots
Abstract: The magnetic nature of sunspots was discovered by G.E. Hale in 1908. Since then, the magnetic field properties were thoroughly studied. I will present the summary of magnetic field properties in sunspots along with brief explanation how to determine the vector of magnetic field in solar photosphere. The aim of our analysis was to determine the magnetic field properties on penumbral boundaries, which were not yet studied explicitly. We tried to determine if the magnetic field strength or inclination is constant on these boundaries and if these values are dependent on sunspot size. The most important result is that the inner penumbral boundaries are defined by the critical value of the vertical component of the magnetic field. This implies that the penumbral filaments have a convective origin.
Dále pořádáme menší semináře jednotlivých oddělení:
Semináře slunečního oddělení
Každé úterý v 13:00 (září–červen, s výjimkou úterků po celoústavním semináři) v zasedací místnosti slunečního oddělení pracoviště Ondřejov.
10/04/2012, 13:00Solar-ionospheric observatory on Proba 2 satelliteAbstract: Coupling between the Earth's ionosphere and the impacting solar radiation and solar wind particles represents one of the essential features of solar-terrestrial relations. Depending on current configuration of the interplanetary magnetic field and magnetosphere, sudden solar events such as solar flares or coronal mass ejections can penetrate the lowest layers of the ionosphere even to very low latitudes and produce strong perturbations to the terrestrial environment. Observational study of these effects shall be enabled by in situ measurements of the plasma content in topside layers of the dawn and dusk side of the ionosphere acquired on Proba 2 mission, particularly by one of the two on board plasma analysers - the Dual Segmented Langmuir Probe. Currently a web based archive is being designed and developed at ASI under ESA contract to provide complete set of DSLP products and catalogue observed ionospheric irregularities with possible relations to sudden solar events.
Zářivě-(magneto)hydrodynamické semináře
Zpravidla 1x za 14 dní ve čtvrtek od 11 hod (říjen–červen) v zasedací místnosti slunečního oddělení pracoviště Ondřejov.
01/12/2011, 11:00Konkoly Observatory, Budapest, HungaryThe extreme outburst of the young eruptive star EX Lupi in 2008Abstract: EX Lupi is the prototype of EXors, a spectacular group of low-mass pre-main sequence stars characterized by repetitive optical outbursts of 1-5 mag lasting for a few months-to-few years. The outburst is attributed to enhanced accretion from the inner circumstellar disk (within ^X0.1AU) to the stellar surface, probably triggered by an instability in the disk. The historically largest outburst of EX Lupi in 2008 Jan-Sep offered a unique opportunity to understand deeper the physics of the EXor eruptions. In my talk I will summarize the main results of our coordinated observing campaign, in which we used a large set of telescopes to observe and characterize the path of accretion from the disk onto the stellar surface, with the aim of comparing the different models of outburst physics. Our measurements also demonstrated that the brief episodes of highly increased accretion, apart from contributing to the build-up of the final stellar mass, have substantial effect on the structure and composition of the circumstellar material: We discovered episodic crystallization of silicate grains in the disk surface due to the increased luminosity during the 2008 outburst, resulting in material that forms the building blocks of comets and planets.
Semináře oddělení GPS
Zpravidla v knihovně pracoviště Praha–Spořilov v různé dny.
V nejbližší době nejsou plánovány žádné semináře.