Astronomický ústav AV ČR   Ondřejov

Fričova 298
251 65 Ondřejov

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Akademie věd
České republiky

 

Přednášky a semináře

Pravidelné semináře pořádáme jednou měsíčně (říjen–červen, zpravidla první pondělí v měsíci) od 13 hod v seminární místnosti pracoviště Ondřejov. (archiv seminářů)

04. 06. 2012
Ondřej Kopáček
Transition from regular to chaotic motion in black hole magnetospheres
Abstract: We study an astrophysical model consisting of the rotating black hole immersed into the asymptotically uniform magnetic field. Structure of the electromagnetic field emerging in the generalized setup involving the oblique background field (misaligned with the rotation axis) and translational motion of the black hole is explored in detail. For a sufficiently rapid drift we localise separator null points of both electric and magnetic fields. The latter are of an utmost interest since they prove that the interplay of the rotation and the drift of the compact body may act as a trigger for magnetic reconnection. Subsequently we study the motion of charged particles in the simplified setup of aligned field. We concern ourselves mainly with the dynamic properties of the trajectories bound in the off-equatorial potential lobes which are relevant for a description of diluted astrophysical coronae. Employing the recurrence analysis we locate transitions between regular and chaotic regimes of motion. Besides the bound off-equatorial orbits we also study trajectories escaping from the equatorial plane in the collimated jet-like structures.
( seminární místnost za 2-metrem)



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.

Program seminářů

27/06/2012, 13:00
Helen Mason
Cambridge University UK
Studies of Active Regions with Hinode/EIS


Zářivě-(magneto)hydrodynamické semináře

Zpravidla 1x za 14 dní ve čtvrtek od 11 hod (říjen–červen) v zasedací místnosti slunečního oddělení pracoviště Ondřejov.

Program seminářů

01/12/2011, 11:00
Peter Abraham
Konkoly Observatory, Budapest, Hungary
The extreme outburst of the young eruptive star EX Lupi in 2008
Abstract: 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.

Program seminářů

V nejbližší době nejsou plánovány žádné semináře.