Molecules with ALMA at Planet-forming Scales (MAPS). XV. Tracing protoplanetary disk structure within 20 au
Abstract
Constraining the distribution of gas and dust in the inner 20 au of protoplanetary disks is difficult. At the same time, this region is thought to be responsible for most planet formation, especially around the water ice line at 3–10 au. Under the assumption that the gas is in a Keplerian disk, we use the exquisite sensitivity of the Molecules with ALMA at Planet-forming Scales (MAPS) ALMA large program to construct radial surface brightness profiles with a ∼3 au effective resolution for the CO isotopologue J = 2–1 lines using the line velocity profile. IM Lup reveals a central depression in 13CO and C18O that is ascribed to a pileup of ∼500 M⊕ of dust in the inner 20 au, leading to a gas-to-dust ratio of around <10. This pileup is consistent with an efficient drift of grains (≳100 M⊕ Myr−1) and a local gas-to-dust ratio that suggests that the streaming instability could be active. The CO isotopologue emission in the GM Aur disk is consistent with a small (∼15 au), strongly depleted gas cavity within the ∼40 au dust cavity. The radial surface brightness profiles for both the AS 209 and HD 163296 disks show a local minimum and maximum in the C18O emission at the location of a known dust ring (∼14 au) and gap (∼10 au), respectively. This indicates that the dust ring has a low gas-to-dust ratio (>10) and that the dust gap is gas-rich enough to have optically thick C18O. This paper is part of the MAPS special issue of the Astrophysical Journal Supplement.
Citation
Bosman , A D , Bergin , E A , Loomis , R A , Andrews , S M , van't Hoff , M L R , Teague , R , Öberg , K I , Guzmán , V V , Walsh , C , Aikawa , Y , Alarcón , F , Bae , J , Bergner , J B , Booth , A S , Cataldi , G , Cleeves , L I , Czekala , I , Huang , J , Ilee , J D , Law , C J , Le Gal , R , Liu , Y , Long , F , Ménard , F , Nomura , H , Pérez , L M , Qi , C , Schwarz , K R , Sierra , A , Tsukagoshi , T , Yamato , Y , Wilner , D J & Zhang , K 2021 , ' Molecules with ALMA at Planet-forming Scales (MAPS). XV. Tracing protoplanetary disk structure within 20 au ' , Astrophysical Journal Supplement Series , vol. 257 , no. 1 , 15 . https://doi.org/10.3847/1538-4365/ac1433
Publication
Astrophysical Journal Supplement Series
Status
Peer reviewed
ISSN
0067-0049Type
Journal article
Description
Funding: J.B., J.B.B., I.C., J.H., K. R.S., and K.Z. acknowledge support by NASA through the NASA Hubble Fellowship grant Nos. HST-HF2-51427.001-A, HST-HF2- 51429.001-A, HST-HF2-51405.001-A, HST-HF2-51460.001-A, HST-HF2-51419.001, and HST-HF2-51401.001, awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Incorporated, under NASA contract NAS5-26555. C.W. acknowledges financial support from the University of Leeds and from the Science and Technology Facilities Council (grant Nos. ST/R000549/1 and ST/T000287/1). A.S.B acknowledges the studentship funded by the Science and Technology Facilities Council of the United Kingdom (STFC). J.D.I. acknowledges support from the Science and Technology Facilities Council of the United Kingdom (STFC) under ST/T000287/1.Collections
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