Observational constraints on dust disk sizes in tidally truncated protoplanetary disks in multiple systems in the Taurus region

Abstract

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.

The magnetic obliquity of accreting T Tauri stars

“…We can see that the modulus of the equivalent width of the He I line's NC is largest when it is most redshifted (on Nov. 25 and Nov. 28), which may be due to a favorable viewing geometry. We have found that the magnetic obliquity of this star is θ = (23 ± 10) • , which agrees, within the uncertainties, with its system inclination of i = (28 ± 1) • (Manara et al 2019). This means that when the accretion shock passes in front of us, we observe the flow of matter onto the star projected almost directly in our line of sight.…”

The effect of stellar multiplicity on protoplanetary discs: a near-infrared survey of the Lupus star-forming region

“…The NIR-Lupus sample presented in this paper consists of the YSOs more massive than brown dwarfs in the Lupus I-IV clouds that have been identified as either Class II or Class III sources. The complete sample includes 125 objects: 95 Class II sources that were observed with ALMA and presented in Ansdell et al (2016Ansdell et al ( , 2018 and 30 Class III objects that were observed with ALMA and presented in Lovell et al (2020).…”

“…The ALMA data for the Class III objects in our Lupus sample were taken during Cycle 8 in Band 7 under program 2018.1.00437.S (PI: Wyatt) and are presented in Lovell et al (2020). This Class III ALMA survey had a moderate resolution of ∼ 0.…”

“…2 resolution for the Class II objects (Ansdell et al 2016(Ansdell et al , 2018 and at ∼0. 7 resolution for the Class III objects (Lovell et al 2020). The sample selection of this NIR survey is presented in Section 2.…”

Planet formation in intermediate-separation binary systems

“…This shows that stellar binarity, and orbital separation in particular, are strongly related to disc mass and hence the ability of discs to form planets. In fact, close-separation binaries are found to have lower disc masses (Jensen et al 1994;Andrews & Williams 2005;Harris et al 2012a;Long et al 2018) and sizes (Manara et al 2019). Furthermore, a survey of excess emission in a large sample of main sequence stars with binary separations of less than 100 au (Rodriguez & Zuckerman 2012) has shown lower debris disc masses in such systems, with possible implications for rocky planet formation and evolution.…”