Parameters of protoplanetary disks in 5 SFRs

We select five nearby star-forming regions that comprise a number of protoplanetary disks with spatially resolved images with ALMA and Hubble Space Telescope, and we search for the mutual alignment of the disk axes. Specifically, we apply the Kuiper test to examine the statistical uniformity of the position angle (PA: the angle of the major axis of the projected disk ellipse measured counterclockwise from the north) distribution.

The disks located in the star-forming regions, except the Lupus clouds, do not show any signature of the alignment, supporting the random orientation. Rotational axes of 16 disks with spectroscopic measurement of PA in the LupusIII cloud, a subregion of the Lupus field, however, exhibit a weak and possible departure from the random distribution at a 2{sigma} level, and the inclination angles of the 16 disks are not uniform as well.