Ripping up a circumstellar disk: During the process of star formation, a disk of gas and dust forms around the young star, controlling the accretion of more material. Once the star has formed, any leftover material in this circumstellar disk can form planets. If a binary or triple star forms at the center of the disk, theoretical models predict that tidal torques caused by their orbits can rip the disk apart, in a process known as disk tearing. Kraus et al. observed the nearby young triple-star system GW Orionis with multiple near-infrared and submillimeter telescopes, using the techniques of interferometry and polarimetry. They found evidence for multiple rings with different orientations and warping of part of the disk, both produced by disk tearing. Science , this issue p. 1233

In order to look for signs of ongoing planet formation in young disks, we carried out the first J-band polarized emission imaging of the Herbig Ae/Be stars HD 150193, HD 163296, and HD 169142 using the Gemini Planet Imager, along with new H band observations of HD 144432. We confirm the complex “double ring” structure for the nearly face-on system HD 169142 first seen in H-band, finding the outer ring to be substantially redder than the inner one in polarized intensity. Using radiative transfer modeling, we developed a physical model that explains the full spectral energy distribution and J- and H-band surface brightness profiles, suggesting that the differential color of the two rings could come from reddened starlight traversing the inner wall and may not require differences in grain properties. In addition, we clearly detect an elongated, off-center ring in HD 163296 (MWC 275), locating the scattering surface to be 18 au above the midplane at a radial distance of 77 au, co-spatial with a ring seen at 1.3 mm by ALMA linked to the CO snow line. Lastly, we report a weak tentative detection of scattered light for HD 150193 (MWC 863) and a non-detection for HD 144432; the stellar companion known for each of these targets has likely disrupted the material in the outer disk of the primary star. For HD 163296 and HD 169142, the prominent outer rings we detect could be evidence for giant planet formation in the outer disk or a manifestation of large-scale dust growth processes possibly related to snow-line chemistry.