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.

Molly Peeples visit

Molly Peeples from Space Telescope Science Institute / Johns Hopkins visited us for a week as part of the Role models in physics program supported by the US Embassy in Prague. She gave a talk on
“Exploring the Universe with Space Telescopes and Supercomputers” and a second talk about “The Universe at Low Density: How Cosmic Gas Flows Build Galaxies”. She talked with students.

Thomas Janka visit

Thomas Janka (MPA Garching) visited to give the department colloquium on core-collapse supernova explosions with a sequel science coffee discussion on kicks, fallback, and nucleosynthesis. He also talked with members of the department. Great to have him visit!

Panel discussion on the next 10 years of astronomy in Czechia

I participated in an event organized to honor 100 years of IAU. I argued that joining SDSS-V would be a good idea to complement existing efforts in photometry and spectroscopy of variable stars, and survey involvement like ASAS-SN and LSST. I also suggested that we should form “International research school in astronomy in Prague/Czech Republic” to attract great PhD students. I learned later that others have proposed similar idea in the past. On a related note, I advocated for establishing “Kepler Postdoctoral Fellowship” to bring excellent early career scientists.

Nadia Zakamska visit

Nadia Zakamska (Johns Hopkins) visited our group and the department this week, giving talks on supermassive black holes and exoplanets. She met with students and postdocs and we also discussed some exciting stellar science. The visit was organized with the help of Role Models in Physics small grant from the US Embassy in Prague.