The SPHERE view of multiple star formation

Abstract

While a large fraction of the stars are in multiple systems, our understanding of the processes leading to the formation of these systems is still inadequate. Given the large theoretical uncertainties, observation plays a basic role. Here we discuss the contribution of high contrast imaging, and more specifically of the SPHERE instrument at the ESO Very Large Telescope, in this area. SPHERE nicely complements other instruments such as Gaia or ALMA—in detecting and characterizing systems near the peak of the binary distribution with separation and allows to capture snapshots of binary formation within disks that are invaluable for the understanding of disk fragmentation.

Effects of environment and multiplicity on planet formation

“…On smaller scales, the multiplicity of the stars is another factor that strongly influences how planets can form in discs. Both Zurlo et al [7] and Gratton et al [8] review how recent observations with ALMA and VLT/SPHERE have deepened our knowledge of discs in multiple systems. In particular, while [8] concentrate on the impact of High Contrast Imaging and in particular on the SPHERE instrument, Zurlo et al [7] describe the interplay of observations at various wavelengths.…”

“…Both Zurlo et al [7] and Gratton et al [8] review how recent observations with ALMA and VLT/SPHERE have deepened our knowledge of discs in multiple systems. In particular, while [8] concentrate on the impact of High Contrast Imaging and in particular on the SPHERE instrument, Zurlo et al [7] describe the interplay of observations at various wavelengths. This wealth of new data is highlighting the importance of several hydrodynamical and dynamical effects, such as disk fragmentation induced by gravitational instabilities and disk tearing/warping induced by disk-orbit misalignment.…”