TY - JOUR
T1 - exoALMA. XV. Interpreting the height of CO emission layer
AU - Rosotti, Giovanni P.
AU - Longarini, Cristiano
AU - Paneque-Carreño, Teresa
AU - Cataldi, Gianni
AU - Galloway-Sprietsma, Maria
AU - Andrews, Sean M.
AU - Bae, Jaehan
AU - Barraza-Alfaro, Marcelo
AU - Benisty, Myriam
AU - Curone, Pietro
AU - Czekala, Ian
AU - Facchini, Stefano
AU - Fasano, Daniele
AU - Flock, Mario
AU - Fukagawa, Misato
AU - Garg, Himanshi
AU - Hall, Cassandra
AU - Huang, Jane
AU - Ilee, John D.
AU - Izquierdo, Andrés F.
AU - Kanagawa, Kazuhiro
AU - Lesur, Geoffroy
AU - Lodato, Giuseppe
AU - Loomis, Ryan A.
AU - Orihara, Ryuta
AU - Pinte, Christophe
AU - Price, Daniel J.
AU - Stadler, Jochen
AU - Teague, Richard
AU - Fernandez, Gaylor Wafflard
AU - Winter, Andrew J.
AU - Wölfer, Lisa
AU - Yen, Hsi-Wei
AU - Yoshida, Tomohiro C.
AU - Zawadzki, Brianna
N1 - Funding:J.B. acknowledges support from NASA XRP grant No. 80NSSC23K1312. M.B., D.F., and J.S. have received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (PROTOPLANETS, grant agreement No. 101002188). Computations by J.S. have been performed on the “Mesocentre SIGAMM” machine, hosted by Observatoire de la Cote d’Azur. P.C. acknowledges support by the Italian Ministero dell’Istruzione, Università e Ricerca through the grant Progetti Premiali 2012 - iALMA (CUP C52I13000140001) and by the ANID BASAL project FB210003. S.F. is funded by the European Union (ERC, UNVEIL, 101076613), and acknowledges financial contribution from PRIN-MUR 2022YP5ACE. M.F. is supported by a Grant-in-Aid from the Japan Society for the Promotion of Science (KAKENHI: No. JP22H01274). J.D.I. acknowledges support from an STFC Ernest Rutherford Fellowship (ST/W004119/1) and a University Academic Fellowship from the University of Leeds. Support for A.F.I. was provided by NASA through the NASA Hubble Fellowship grant No. HST-HF2-51532.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5-26555. C.L. has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No. 823823 (DUSTBUSTERS) and by the UK Science and Technology research Council (STFC) via the consolidated grant ST/W000997/1. C.P. acknowledges Australian Research Council funding via FT170100040, DP18010423, DP220103767, and DP240103290. D.P. acknowledges Australian Research Council funding via DP18010423, DP220103767, and DP240103290. G.R. acknowledges funding from the Fondazione Cariplo, grant No. 2022-1217, and the European Research Council (ERC) under the European Union’s Horizon Europe Research & Innovation Programme under grant agreement No. 101039651 (DiscEvol). H.-W.Y. acknowledges support from National Science and Technology Council (NSTC) in Taiwan through grant NSTC 113-2112-M-001-035- and from the Academia Sinica Career Development Award (AS-CDA-111-M03). G.W.F. acknowledges support from the European Research Council (ERC) under the European Union Horizon 2020 research and innovation program (grant agreement No. 815559 (MHDiscs)). G.W.F. was granted access to the HPC resources of IDRIS under the allocation A0120402231 made by GENCI. Support for B.Z. was provided by The Brinson Foundation. C.H. acknowledges support from NSF AAG grant No. 2407679. G.L. has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No. 823823 (DUSTBUSTERS). T.C.Y. acknowledges support by Grant-in-Aid for JSPS Fellows JP23KJ1008. A.J.W. has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No 101104656. T.P.-C. thanks the Heising-Simons Foundation for their funding through the 51 Pegasi b Postdoctoral Fellowship.
PY - 2025/5/1
Y1 - 2025/5/1
N2 - The availability of exquisite data and the development of new analysis techniques have enabled the study of emitting heights in protoplanetary disks. In this paper, we introduce a simple model linking the emitting height of CO to the disk surface density and temperature structure. We then apply the model to measurements of the emitting height and disk temperature conducted as part of exoALMA, integrated with additional legacy measurements from the MAPS Large Programme, to derive CO column densities and surface density profiles (assuming a CO abundance) for a total of 14 disks. A unique feature of the method we introduce to measure surface densities is that it can be applied to optically thick observations, rather than optically thin as conventionally done. While we use our method on a sample of well-studied disks where temperature structures have been derived using two emission lines, we show that reasonably accurate estimates can be obtained also when only one molecular transition is available. With our method, we obtain independent constraints from 12CO and 13CO, and we find they are in general good agreement using the standard 12C/13C isotopic ratio. The masses derived from our method are systematically lower compared with the values derived dynamically from the rotation curve if using an interstellar matter (ISM) CO abundance, implying that CO is depleted by a median factor ∼20 with respect to the ISM value, in line with other works that find that CO is depleted in protoplanetary disks.
AB - The availability of exquisite data and the development of new analysis techniques have enabled the study of emitting heights in protoplanetary disks. In this paper, we introduce a simple model linking the emitting height of CO to the disk surface density and temperature structure. We then apply the model to measurements of the emitting height and disk temperature conducted as part of exoALMA, integrated with additional legacy measurements from the MAPS Large Programme, to derive CO column densities and surface density profiles (assuming a CO abundance) for a total of 14 disks. A unique feature of the method we introduce to measure surface densities is that it can be applied to optically thick observations, rather than optically thin as conventionally done. While we use our method on a sample of well-studied disks where temperature structures have been derived using two emission lines, we show that reasonably accurate estimates can be obtained also when only one molecular transition is available. With our method, we obtain independent constraints from 12CO and 13CO, and we find they are in general good agreement using the standard 12C/13C isotopic ratio. The masses derived from our method are systematically lower compared with the values derived dynamically from the rotation curve if using an interstellar matter (ISM) CO abundance, implying that CO is depleted by a median factor ∼20 with respect to the ISM value, in line with other works that find that CO is depleted in protoplanetary disks.
KW - Planet formation
KW - Protoplanetary disks
UR - https://www.scopus.com/pages/publications/105004229590
U2 - 10.3847/2041-8213/adc42e
DO - 10.3847/2041-8213/adc42e
M3 - Article
AN - SCOPUS:105004229590
SN - 2041-8205
VL - 984
JO - Astrophysical Journal Letters
JF - Astrophysical Journal Letters
IS - 1
M1 - L20
ER -