📈 PROTOPLANETARY DISK DEMOGRAPHICS 📉
I like large sample sizes + statistics. For my PhD thesis, I conducted demographic surveys of protoplanetary disks using *a lot* of radio telescopes (more officially known as ALMA) to better understand how planets form. Some of the resulting pretty pictures are shown below, and the accompanying science can be found in Ansdell et al. 2016c and Ansdell et al. 2018b. The ALMA images below are detecting thermal heat emission from the dust grains in the protoplanetary disks that are orbiting around unseen stars (we don't see the stars because stars don't emit very much at radio wavelengths, but dust does). My favorite is J16070384-3911113 (but don't tell the others).
🔥Another cool thing we discovered with our ALMA surveys was evidence for external photoevaporation---basically when really bright/massive stars (the ones that eventually go supernova) strip away planet-forming material around other smaller stars like our Sun--- even in low-FUV environments. That is what's causing the trend between distance from σ Ori (the massive star in the cluster) and the mass of protoplanetary disks around the surrounding stars (see Ansdell et al. 2017 for the deets).
💫 INNER DISK DYNAMICS WITH "DIPPER" STARS 💫
My side project while working on my PhD thesis produced the same amount of papers as my actual thesis (fun fact: this sub-sub-section in my 95-page thesis was 10 pages long...oops). This research used light curves from the Kepler spacecraft to study stars that exhibit big dimming events, likely due to large dusty structures orbiting in the inner disk very close to the star. This was a nice complement to the radio images show above, which cover the outer regions of the disk. Below are some of examples of these "dipper" light curves (see more in Ansdell et al. 2016a).
🤯 By combining the Kepler light curves probing the inner disk and the ALMA data probing the outer disk, we have also shown that misalignments between the inner and outer disk could be common around young stars (Ansdell et al. 2016b, Ansdell et al. 2020), which would provide a very different picture of disk evolution and planet formation from what I learned in grad school.