Artículos de revistas
Molecules with ALMA at Planet-forming Scales (MAPS). IV. Emission Surfaces and Vertical Distribution of Molecules
Fecha
2021Registro en:
The Astrophysical Journal Supplement Series, 257:4 (24pp), 2021 November
10.3847/1538-4365/ac1439
Autor
Law, Charles J.
Teague, Richard
Loomis, Ryan A.
Bae, Jaehan
Oberg, Karin
Czekala, Ian
Andrews, Sean M.
Aikawa, Yuri
Alarcón, Felipe
Bergin, Edwin A.
Bergner, Jennifer B.
Booth, Alice S.
Bosman, Arthur D.
Calahan, Jenny K.
Cataldi, Gianni
Cleeves, Ilsedore
Furuya, Kenji
Guzmán, Viviana V.
Huang, Jane
Ilee, John D.
Le Gal, Romane
Liu, Yao
Long, Feng
Menard, Francois
Nomura, Hideko
Pérez Muñoz, Laura
Qi, Chunhua
Schwarz, Kamber R.
Soto, Daniela
Tsukagoshi, Takashi
Yamato, Yoshihide
Van 't Hoff, Merel L. R.
Walsh, Catherine
Wilner, David J.
Zhang, Ke
Institución
Resumen
The Molecules with ALMA at Planet-forming Scales (MAPS) Large Program provides a unique opportunity to
study the vertical distribution of gas, chemistry, and temperature in the protoplanetary disks around IM Lup,
GM Aur, AS 209, HD 163296, and MWC 480. By using the asymmetry of molecular line emission relative to the
disk major axis, we infer the emission height (z) above the midplane as a function of radius (r). Using this method,
we measure emitting surfaces for a suite of CO isotopologues, HCN, and C2H. We find that 12CO emission traces
the most elevated regions with z r > 0.3, while emission from the less abundant 13CO and C18O probes deeper
into the disk at altitudes of z r 0.2. C2H and HCN have lower opacities and signal-to-noise ratios, making
surface fitting more difficult, and could only be reliably constrained in AS 209, HD 163296, and MWC 480, with
z r 0.1, i.e., relatively close to the planet-forming midplanes. We determine peak brightness temperatures of
the optically thick CO isotopologues and use these to trace 2D disk temperature structures. Several CO temperature
profiles and emission surfaces show dips in temperature or vertical height, some of which are associated with gaps
and rings in line and/or continuum emission. These substructures may be due to local changes in CO column
density, gas surface density, or gas temperatures, and detailed thermochemical models are necessary to better
constrain their origins and relate the chemical compositions of elevated disk layers with those of planet-forming
material in disk midplanes. This paper is part of the MAPS special issue of the Astrophysical Journal Supplement.