Author: opejcha

Bachelor & Master thesis topics

I am looking for Bachelor & Master students. Here is a (non-exhaustive) list of possible topics:

  • Dynamical perturbations of triple stellar and planetary systems seen in gravitational waves with LISA
  • Looking over the cliff: when do close binary stars merge?
  • Combining astrometry a variability information from the Gaia satellite
  • Radiation transport on exploding background and applications to supernovae, stellar mergers, and classical novae
  • Stellar merger model for the progenitor of SN1987A

All topics are related to research of current interest supported by grants and should result in one or more scientific papers. The thesis topic is always finalized upon discussions with the student. The methods of work include semi-analytic calculations, (radiation) hydrodynamics, and statistical analysis of data.

On the triple-star origin of the planetary nebula Sh 2-71

In a paper led by David Jones with Romano Corradi from La Palma we tried to come up with a theory to explain the peculiar shape (including new distant emission regions firstly presented here) and central stars of the planetary nebula. Our preferred models includes Lidov-Kozai cycles and triple star disruption due to ejection of the planetary nebula.

Paper now accepted to MNRAS:https://arxiv.org/abs/1908.04582v1

Kinematics of Mass Loss from L2

Dominika Hubova expanded her Bachelor thesis and took the deepest look so far at ballistic mass loss from L2, focusing on what happens if the matter stream is initiated with offset from L2 and with a velocity kick. Dominika characterized the parameter space and found some new stream trajectories. Interestingly, even if the stream is launched slower than corotation, there are still many initial positions near L2 that provide sufficient tidal torque to unbind the material.

Paper is now accepted to MNRAS: https://arxiv.org/abs/1908.02659v1

Periodic Variables in the APOGEE Survey

A paper characterizing periodic and aperiodic variability of APOGEE targets with ASAS-SN data was recently accepted to MNRAS. In this effort led by Michał Pawlak, we characterized almost 2000 periodic variable stars, all with existing multi-epoch high-resolution spectroscopy from APOGEE. We found that eclipsing binaries tend to favor lower metallicities, as was recently found on purely spectroscopic samples. We characterized the variability with damped random walk stochastic process. This is a starting point for future investigations combining high-res spectroscopy from surveys with time-domain photometric information. The paper is available on astro-ph.