Substructures in Compact Disks of the Taurus Star-forming Region

Abstract

Observations of substructure in protoplanetary disks have largely been limited to the brightest and largest disks, excluding the abundant population of compact disks, which are likely sites of planet formation. Here, we reanalyze ∼0.″1, 1.33 mm Atacama Large Millimeter/submillimeter Array (ALMA) continuum observations of 12 compact protoplanetary disks in the Taurus star-forming region. By fitting visibilities directly, we identify substructures in six of the 12 compact disks. We then compare the substructures identified in the full Taurus sample of 24 disks in single-star systems and the ALMA DSHARP survey, differentiating between compact (R eff,90% < 50 au) and extended (R eff,90% ≥50 au) disk sources. We find that substructures are detected at nearly all radii in both small and large disks. Tentatively, we find fewer wide gaps in intermediate-sized disks with R eff,90% between 30 and 90 au. We perform a series of planet–disk interaction simulations to constrain the sensitivity of our visibility-fitting approach. Under the assumption of planet–disk interaction, we use the gap widths and common disk parameters to calculate potential planet masses within the Taurus sample. We find that the young planet occurrence rate peaks near Neptune masses, similar to the DSHARP sample. For 0.01 M J/M ⊙ ≲M p/M * ≲0.1 M J/M ⊙, the rate is 17.4% ± 8.3%; for 0.1 M J/M ⊙ ≲M p/M * ≲1 M J/M ⊙, it is 27.8% ± 8.3%. Both of them are consistent with microlensing surveys. For gas giants more massive than 5 M J, the occurrence rate is 4.2% ± 4.2%, consistent with direct imaging surveys.

JWST Reveals Excess Cool Water near the Snow Line in Compact Disks, Consistent with Pebble Drift

“…While compact disks may have narrow gaps at <30 au that remain unresolved by ALMA, none have been reported for the two compact disks in our sample, even using superresolution techniques (Jennings et al 2022a(Jennings et al , 2022bZhang et al 2023). Further, shallow gaps in inner disks may be very leaky and effectively produce little or no reduction in inner water enrichment (Kalyaan et al 2023).…”

“…We note that HP Tau might have a small inner dust cavity, as suggested by the relatively high infrared index n 13-26 measured in MIRI spectra instead of the Spitzer-based n 13-30 index (see Appendix D in Banzatti et al 2020). The ALMA image with 0 12 resolution does not resolve this putative cavity, even with superresolution techniques (Jennings et al 2022b;Zhang et al 2023), suggesting that the cavity, if present, is smaller than <2 au in width (the smallest dust structure detected with this technique in disks).…”

Small and Large Dust Cavities in Disks around Mid-M Stars in Taurus

“…Taking disks in Taurus as an example (Hashimoto et al 2021;Kurtovic et al 2021;this work), high spatial resolution imaging revealed 7 disks with cavities out of 13 disks around M3-M6 stars. In comparison to stars earlier than M3 in Taurus, only 4 out of 32 disks analyzed by Long et al (2019) show cavities (5/32 considering the reanalysis in Zhang et al 2023). However, the sample around mid-to late M stars used here might be more biased than that in Long et al (2019).…”

Searching for Giant Exoplanets around M-dwarf Stars (GEMS) I: Survey Motivation

“…These trends were extended to very low-mass stars and brown dwarfs using high-angular resolution observations from the Atacama Large Millimeter/submillimeter Array (ALMA), which suggested the presence of substructures in a fraction of these disks (Pinilla 2022). Zhang et al (2023) perform a similar analysis and compare the incidence of structures in disks in the Taurus star-forming region to infer the occurrence of protoplanets as a function of the stellar mass and orbital separation.…”