Early Planet Formation in Embedded Disks (eDisk): Demographics of Embedded Disks

Nagayoshi Ohashi^1*

¹Institute of Astronomy & Astrophysics, Academia Sinica, Taipei, Taiwan

* Presenter:Nagayoshi Ohashi, email:ohashi@asiaa.sinica.edu.tw

Disks are known to form around young stellar objects as a natural outcome of the star formation process. Although they originate as by-products, these disks play critical roles in both star and planet formation. Disks around Class II sources—commonly referred to as protoplanetary disks—have received significant attention, as they are thought to represent the main phase of planet formation. In contrast, disks around embedded protostars, which are younger and more deeply embedded, have been comparatively understudied.

Recent research, however, highlights the importance of embedded disks in setting the initial conditions for planet formation, motivating the need for a more systematic investigation of their properties. To this end, we have conducted the ALMA Large Program "Embedded Disks in Early Planet Formation (eDisk)", targeting 19 protostars in nearby star-forming regions. The survey includes 1.3 mm continuum observations at ~0.04″ resolution and molecular line observations (e.g., CO isotopologues) at ~0.1″ resolution.

This program enables, for the first time, a systematic demographic analysis of embedded disk properties—such as mass and size—and their relation to the central protostar. In this presentation, I will review the main observational results from the eDisk program, with a focus on emerging demographic trends and their implications for disk evolution and early planet formation.

Keywords: protostar, star and planet formation, protoplanetary disk