It was a day packed with non-research, except for group meeting, which was great, as always. Sanderson updated us on extensions of her action-space clustering methods for measuring the Milky Way gravitational potential. One of the ideas that emerged in the discussion relates to "extended distribution functions": In principle any stellar "tags" or labels or parameters that correlate with substructure identification could help in finding or constraining potential parameters. Even very noisy chemical-abundance labels might in principle help a lot. That's worth checking. Also, chemical labels that have serious systematics are not necessarily worse than labels that are "good" in an absolute sense. That is one of my great hopes: That we don't need good models of stars to do things very similar to chemical tagging.
Also in group meeting we gave Hattori marching orders for (a) getting a final grade on his independent study and then (b) getting to fly to Hawaii for the exoplanet stats meeting. For the former, he needs to complete a rudimentary search of all stars in Kepler. For the latter he needs to do hypothesis tests on the outcome of the search and write it up!