Molecules with ALMA at Planet-forming Scales (MAPS). XIII. HCO + and Disk Ionization Structure
In: The Astrophysical Journal Supplement Series ; https://hal-insu.archives-ouvertes.fr/insu-03672367 ; The Astrophysical Journal Supplement Series, 2021, 257, ⟨10.3847/1538-4365/ac143c⟩, 2021
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Zugriff:
International audience ; We observed HCO + J = 1 - 0 and H 13 CO + J = 1 - 0 emission toward the five protoplanetary disks around IM Lup, GM Aur, AS 209, HD 163296, and MWC 480 as part of the MAPS project. HCO + is detected and mapped at 0"3 resolution in all five disks, while H 13 CO + is detected (S/N > 6σ) toward GM Aur and HD 163296 and tentatively detected (S/N > 3σ) toward the other disks by a matched filter analysis. Inside a radius of R ~ 100 au, the HCO + column density is flat or shows a central dip. At outer radii (≳100 au), the HCO + column density decreases outward, while the column density ratio of HCO + /CO is mostly in the range of ~10 -5 -10 -4 . We derived the HCO + abundance in the warm CO-rich layer, where HCO + is expected to be the dominant molecular ion. At R ≳ 100 au, the HCO + abundance is ~3 × 10 -11 - 3 × 10 -10 , which is consistent with a template disk model with X-ray ionization. At the smaller radii, the abundance decreases inward, which indicates that the ionization degree is lower in denser gas, especially inside the CO snow line, where the CO-rich layer is in the midplane. Comparison of template disk models with the column densities of HCO + , N 2 H + , and N 2 D + indicates that the midplane ionization rate is ≳10 -18 s -1 for the disks around IM Lup, AS 209, and HD 163296. We also find hints of an increased HCO + abundance around the location of dust continuum gaps in AS 209, HD 163296, and MWC 480. This paper is part of the MAPS special issue of the Astrophysical Journal Supplement.
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Molecules with ALMA at Planet-forming Scales (MAPS). XIII. HCO + and Disk Ionization Structure
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Autor/in / Beteiligte Person: | Aikawa, Yuri ; Cataldi, Gianni ; Yamato, Yoshihide ; Zhang, Ke ; Booth, Alice S. ; Furuya, Kenji ; Andrews, Sean M. ; Bae, Jaehan ; Bergin, Edwin A. ; Bergner, Jennifer B. ; Bosman, Arthur D. ; Cleeves, L. Ilsedore ; Czekala, Ian ; Guzmán, Viviana V. ; Huang, Jane ; Ilee, John D. ; Law, Charles J. ; Le Gal, Romane ; Loomis, Ryan A. ; Ménard, François ; Nomura, Hideko ; Öberg, Karin I. ; Qi, Chunhua ; Schwarz, Kamber R. ; Teague, Richard ; Tsukagoshi, Takashi ; Walsh, Catherine ; Wilner, David J. ; Institut de Planétologie et d'Astrophysique de Grenoble (IPAG) ; Centre National d'Études Spatiales Toulouse (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ) ; Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France |
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Zeitschrift: | The Astrophysical Journal Supplement Series ; https://hal-insu.archives-ouvertes.fr/insu-03672367 ; The Astrophysical Journal Supplement Series, 2021, 257, ⟨10.3847/1538-4365/ac143c⟩, 2021 |
Veröffentlichung: | HAL CCSD, 2021 |
Medientyp: | academicJournal |
DOI: | 10.3847/1538-4365/ac143c |
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