Science highlight: Large planet-forming disks hiding in the ALMA archive

ALMA has altered our view of planet-forming disks forever. High resolution imaging with ALMA has shown that forming or already-formed planets carve a rich structure in their natal disks. Surveys of thousands of disks around T Tauri stars (young stars with masses up to 1 Solar mass) have produced a thorough census of the mass and size of these disks. Surprisingly, ALMA has never systematically studied the disks around the higher-mass (1-10 Solar mass) Herbig Ae/Be stars. Luckily, many Herbig disks have been observed through individual programs. In a recently published paper, Stapper et al. (2022, A&A 658, A112), explore the ALMA Archive for Herbig disks using the Allegro-developed archive mining tool ALminer. They uncover data on 36 Herbig disks out to 450 pc, which produces a volume-limited sample that is complete to 64% within 225 pc and to 38% within 450 pc: sufficient for a population study. Stapper et al. find that Herbig disks are on average 3-7 times more massive than the typical disk around a T Tauri star, and also likely larger. However, there is a distinct sub-population of Herbig disks that have as little mass as T Tauri disks, and there are a few T Tauri disks that are as massive and large as many of the Herbig disks. Stapper et al. hypothesise that the different mass distributions between Herbig and T Tauri disks reflect the different probabilities of disks around these two types of stars to form gas giant planets that can carve gaps and trap large mass reservoirs in the outer disk. This work illustrates the science that can be done by mining the ALMA archive.