Pravidelné semináře pořádáme jednou měsíčně (říjen–červen, zpravidla první pondělí v měsíci) od 13 hod v seminární místnosti pracoviště Ondřejov. (archiv seminářů)
16. 01. 2012
3D radiative transfer in clumped hot star winds
Dále pořádáme menší semináře jednotlivých oddělení:
Semináře slunečního oddělení
Každé úterý v 12:45 (září–červen, s výjimkou úterků po celoústavním semináři) v zasedací místnosti slunečního oddělení pracoviště Ondřejov.
10/01/2012, 13:00CLASP: A sounding rocket experiment for spectropolarimetry of the Lyman alpha lineAbstract: Knowledge of the magnetic field structure of the upper chromosphere and transition region is crucial to address several major unresolved issues of solar physics (coronal heating, acceleration of solar wind). However, our empirical knowledge of this region remains quite poor. The purpose of the international project Chromospheric Lyman-Alpha SpectroPolarimeter (CLASP) is to observe and interpret spectropolarimetric signals in the Lyman-alpha line of hydrogen at 1216 A. Depending on the success of the mission, it may justify a UV/FUV spectropolarimeter onboard the future spacecrafts (e.g., Solar-C). In this talk, I will briefly review the fundamental ingredients of the polarized line formation (scattering polarization, radiative transfer, Hanle effect) understanding of which is necessary for inferring quantitative information on the magnetic fields. Using the numerical non-LTE modeling in 1D, 2D and 3D geometries, I will show under which conditions we will be able to obtain such information from the observations of the proposed instrument.
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.