plots, WDs, and chemistry at group meetings

Group meetings were fun today. In Gaia DR2 prep meeting, I worked with Megan Bedell (Flatiron) to get some plots ready for Gaia DR2. That is, we planned what we will plot the moment that the data release happens. The goal is to look at physical and kinematic properties of exoplanet host stars.

In Stars meeting, JJ Hermes (UNC) showed some incredible WD lightcurves, which appear to come from white dwarfs that have quadrupolar temperature distortions on their surfaces, rotating. There appears to be a common sub-type of white dwarfs that show evidence of magnetism and strong surface temperature variations. We discussed things to do with Gaia and other data sources.

John Brewer (Yale) showed hot-off-the-presses results on chemical-abundance variations within Praesepe. This cluster has some really strange properties, like an amazingly low velocity dispersion. But he finds a chemical-abundance variation in iron but also elements ratioed to iron. This is in qualitative disagreement with work I have done with Melissa Ness (Columbia), so there is something to work out there. We discussed critical tests of his methods and results.

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