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PhD. Topics

Astronomical Institute

Formation of young stars of T Tauri type and their planetary systems
PhD. program
Astronomy and Astrophysics
Name of the supervisor
Mgr. Martin Vaňko, PhD.
Receiving school
Faculty of Mathematics, Physics and Informatics
Context: T Tauri are young (up to 100 Myr), low mass (less than 3 solar masses) highly variable late-type (later than F-type) stars with peculiar emission line spectra, associated with nearby molecular clouds the Star-Forming Regions (SFR, e.g. Rho Ophiuchi cloud complex, Orion Nebula, Taurus-Auriga, Cepheus-Cassiopeia). Their spectra also show high abundance of lithium with respect to that of the Sun and other main-sequence stars. T Tau stars are divided into two subgroups:(i) classical" TTS always embedded in a circumstellar envelope (CTTS), and (ii) the "weak-line" TTS with no longer indicated circumstellar envelope (WTTS). It has been found that TTS, in particular of the WTTS type, can be associated with strong X-ray emission and high rotation velocities (tens of km/s). High-resolution near-IR surveys indicate that a majority of the young stars are binaries or multiple systems with a typical separation of 0.3 - 0.5 arcsec. A study of TTS, in particular within binaries and multiple systems, allows us to better understand their origin and evolution until the stage when they will start to shine in the optical and become normal stars, as well as possible formation of their planetary systems.
Aims: Follow-up observations for candidate T Tauri stars and modelling of binary components containing a few Myr young stars to determine their physical parameters, rotational periods, character and nature of the observed photometric variability. Acquiring of multicolour photometry (including much desired U-band) of selected T Tauri stars.
Methods: Photometric monitoring of selected objects in the Cepheus-Cassiopeia region using telescopes of AI SAS. Spectroscopic observations will be used to obtain radial velocity curves and to detect the Li 670.8 nm line, as an indicator of the age. The selected targets are suitable for observations with échelle spectrograph eShel (R=11000, Shelyak Instruments) mounted at 60-cm Cassegrain telescope in the pavilion G1 at the Stará Lesná observatory, and with 1.3-m Nasmyth-Cassegrain telescope at Skalnaté Pleso observatory (https://www.ta3.sk/l3.php?p3=sto).

English language, programming skills, physical basis

Affiliation: Astronomical Institute of the Slovak Academy of Sciences, The Department of Solar Physics, Tatranska Lomnica

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