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A star with a mid-IR excess (circumstellar disk?) that vanishes in a 2-year interval.

Deason et al have an improved measurement of density and velocities of blue horizontal branch stars in the MW halo: here they fit dynamical models an infer a halo of about 1e12 Msun (as before) and quite a high concentration (cvir~20). Since concentration reflects age, this is consistent with the picture in which the MW has been undisturbed for a long time.

The chameleon mechanism suppresses the effects of a modified gravity theory in high-density environments. The authors of this paper suggest that this could lead to effects on stellar structure that would impact distance measures inferred from cepheid variables and red giant branch stars. Whilst it's not clear that the astrophysics involved is sufficiently well understood for such tests to be useful, I think there is some good thinking-outside-the-box here!

Rather than being split up into two components of different aged stellar populations with distinct scale heights, a thin and thick disc, the Milky Way seems to have "a continuous and monotonic distribution of disk thicknesses".

That's not what Lucio Meyer said!

Interesting letter discussing re-ionizing the universe through accretion shocks around massive halos in the early universe.