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Title: MAPS: Constraining Serendipitous Time Variability in Protoplanetary Disk Molecular Ion Emission
Abstract

Theoretical models and observations suggest that the abundances of molecular ions in protoplanetary disks should be highly sensitive to the variable ionization conditions set by the young central star. We present a search for temporal flux variability of HCO+J= 1–0, which was observed as a part of the Molecules with Atacama Large Millimeter/submillimeter Array (ALMA) at Planet-forming Scales ALMA Large Program. We split out and imaged the line and continuum data for each individual day the five sources were observed (HD 163296, AS 209, GM Aur, MWC 480, and IM Lup, with between three and six unique visits per source). Significant enhancement (>3σ) was not observed, but we find variations in the spectral profiles in all five disks. Variations in AS 209, GM Aur, and HD 163296 are tentatively attributed to variations in HCO+flux, while variations in IM Lup and MWC 480 are most likely introduced by differences in theuvcoverage, which impact the amount of recovered flux during imaging. The tentative detections and low degree of variability are consistent with expectations of X-ray flare-driven HCO+variability, which requires relatively large flares to enhance the HCO+rotational emission at significant (>20%) levels. These findings also demonstrate the need for dedicated monitoring campaigns with high signal-to-noise ratios to fully characterize X-ray flare-driven chemistry.

 
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Award ID(s):
1907832
NSF-PAR ID:
10468872
Author(s) / Creator(s):
; ; ; ; ; ; ; ; ; ; ; ; ; ;
Publisher / Repository:
DOI PREFIX: 10.3847
Date Published:
Journal Name:
The Astrophysical Journal
Volume:
956
Issue:
2
ISSN:
0004-637X
Format(s):
Medium: X Size: Article No. 103
Size(s):
["Article No. 103"]
Sponsoring Org:
National Science Foundation
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