Presented here is the Taurus star-forming region, with the background image showing the 100 μm emission as seen by the IRAS satellite, and the insets showing various young stars observed with SPHERE at 1.2–2.1 μm (J, H, K bands). Note that the scales of the insets are not consistent; they have been adjusted for visibility. The largest (AB Aur) spans 9 arcseconds. The 43 objects within the insets, which together represent about a fifth of the planet-forming disks in Taurus, are mostly of similar age (1–3 Myr) but are at diverse evolutionary stages. There are 36 low-mass, nine solar-mass and ten intermediate-mass stars (some systems include multiple stars).
SPHERE observes the light scattered by dust in and around young star systems, and can measure indicative parameters such as the polarized-to-stellar light contrast (αpol). Using αpol, Garufi et al. split the sample into three groups: faint disks, bright disks and systems where there is extended emission originating from ambient material. Twenty-seven sources fall into the ‘faint disk’ category (for example, CI Tau and DH Tau). Typically these disks lack any obvious substructure, indicating that the sensitivity and resolution of SPHERE are not sufficient to detect it. In contrast, the eight bright disks (for example, GG Tau, GM Aur) all show evidence of substructure, including cavities, shadows, spirals and streamers. The remaining systems (including T Tau and HP Tau) do not have scattered-light disks. They are probably more evolved systems, with central cavities that allow optical photons to escape. Interestingly, the central portions of Taurus host mostly faint, isolated disks while the outskirts have brighter, interacting disks; this does not seem to be an interstellar extinction effect, but could be related to stellar mass or the evolutionary history of the region.
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