Instrumental setup and data reduction ALMA setup. ALMA Band 7 observations of HD142527 were carried out in the night of June 2 2012. The precipitable water vapor in the atmosphere was stable between 1.4 and 1.8 mm, with clear sky conditions. The ALMA correlator was configured in the Frequency Division Mode (FDM) to provide 468.750 MHz bandwidth in four different spectral windows at 122.07 kHz resolution (0.1 km/s) per channel. Each spectral window was positioned in order to target the CO(3-2) transition at 345.7959 GHz, HCO+ as well as CS(7-6) and HCN(4-3). The measured system temperatures ranged from 207 to 285 K in the different spectral windows. The number of 12 m antennas available at the time of the observation was 19, although two antennas reported very large system temperatures (DA41 and DV12) and were flagged during data reduction. Excluding calibration overheads, a total time on source of 52 minutes was spent yielding an RMS of 15 mJy in 0.1 km s −1 channels. The primary flux calibrator was Titan, which provided a mean transferred flux of 14.2 Jy for 3c279, the bandpass calibrator, and 0.55 Jy for J1604-446, the phase calibrator. Amplitude calibration used the CASA Butler-JPL-Horizons 2010 model for Titan, which gives an estimated systematic flux uncertainty of ⇠10%. All the line data were processed with continuum subtraction in the visibility domain. Image synthesis. Image synthesis was performed using two different techniques, depending on the application. For a traditional way to present the visibility dataset we use Cotton-Schwab CLEAN in the CASA package. This technique represents the consensus in image synthesis. We use Briggs weighting with robustness parameter of zero. For deconvolved models we use a non-parametric least-squares modeling technique 31 with a regularizing entropy term (i.e. as in the family of maximum entropy methods, MEM here and elsewhere). MEM model images are restored by convolving with the clean beam and by adding the residuals calculated using the difmap package 32. For the residuals we use weights comparable to our choice in CASA, a mixture of natural and uniform weights. A detailed example of this MEM algorithm is shown in the HCO + channel maps, Fig. S4. 1 Registration of ALMA images. A ⇠0.1 arcsec astrometric uncertainty could affect the ALMA data. However, we checked the astrometry by confirming that the centroid of the Keplerian velocity field (seen in the RGB image for CO(3-2) in Fig. 1) lies indeed at the po

Accurate measurements of the physical structure of protoplanetary discs are critical inputs for planet formation models. These constraints are traditionally established via complex modelling of continuum and line observations. Instead, we present an empirical framework to locate the CO isotopologue emitting surfaces from high spectral and spatial resolution ALMA observations. We apply this framework to the disc surrounding IM Lupi, where we report the first direct, i.e. model independent, measurements of the radial and vertical gradients of temperature and velocity in a protoplanetary disc. The measured disc structure is consistent with an irradiated self-similar disc structure, where the temperature increases and the velocity decreases towards the disc surface. We also directly map the vertical CO snow line, which is located at about one gas scale height at radii between 150 and 300 au, with a CO freeze-out temperature of 21 ± 2 K. In the outer disc (> 300 au), where the gas surface density transitions from a power law to an exponential taper, the velocity rotation field becomes significantly sub-Keplerian, in agreement with the expected steeper pressure gradient. The sub-Keplerian velocities should result in a very efficient inward migration of large dust grains, explaining the lack of millimetre continuum emission outside of 300 au. The sub-Keplerian motions may also be the signature of the base of an externally irradiated photo-evaporative wind. In the same outer region, the measured CO temperature above the snow line decreases to ≈ 15 K because of the reduced gas density, which can result in a lower CO freeze-out temperature, photo-desorption, or deviations from local thermodynamic equilibrium.

The impact of stellar multiplicity on the evolution of planet-forming disks is still the subject of debate. Here we present and analyze disk structures around ten multiple stellar systems that were included in an unbiased, high spatial resolution survey performed with ALMA of 32 protoplanetary disks in the Taurus star-forming region. At the unprecedented spatial resolution of ∼0.12 we detect and spatially resolve the disks around all primary stars, and those around eight secondary and one tertiary star. The dust radii of disks around multiple stellar systems are smaller than those around single stars in the same stellar mass range and in the same region. The disks in multiple stellar systems also show a steeper decay of the millimeter continuum emission at the outer radius than disks around single stars, suggestive of the impact of tidal truncation on the shape of the disks in multiple systems. However, the observed ratio between the dust disk radii and the observed separation of the stars in the multiple systems is consistent with analytic predictions of the effect of tidal truncation only if the eccentricities of the binaries are rather high (typically >0.5) or if the observed dust radii are a factor of two smaller than the gas radii, as is typical for isolated systems. Similar high-resolution studies targeting the gaseous emission from disks in multiple stellar systems are required to resolve this question.