The Milky Way Mapper meeting continued today. Both yesterday and today there were great presentations on asteroseismology in NASA TESS that might impact our target selection. The Hekker group here in Goettingen is doing a number of relevant things, including feature engineering for long-period asteroseismological inference in short time streams (which connects to things we have been thinking about for stellar rotation in TESS), and fully automated delivery of asteroseismic parameters for red giants. Short presentations on all this were given by Bell, Kuszlewicz. and Themessl (all Goettingen). I had a good discussion with all of this crew at lunch today, where they were pretty pessimistic about my ideas about getting asteroseismological parameters out of the ESA Gaia data (in some late DR).
In a coffee break, Rix (MPIA) asked me a nice homework problem about time-domain spectroscopy, inspired by things he is thinking about with Dani Maoz (TAU): If you have exactly two observations of a star, separated by time interval Δt, and these deliver (a precise) difference in radial velocity Δv, what can you conclude about the orbital parameters of that star? Assume the star is orbiting a dark companion on a circular orbit, and your measurements are so precise, the measurement uncertainty is irrelevant.
In a discussion led by Bird (Vandy) about signal-to-noise, Blanton (NYU) pointed out that the APOGEE detectors are up-the-ramp, so we can sub-frame them to a shorter exposure without making any approximations! That's incredible! It means that we could be doing time-domain astronomy with APOGEE on time-scales that are not accessible to any optical spectrograph. I got super-excited about this, and tried to convince Nidever (Montana) to get in there and make that change. He opined that it might not be trivial. However, the information is definitely there, latent. So my question is: What's the killer app for such technology? We can look at spectral variability information on essentially any time scale from seconds to hours. Woah.
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