It has been proposed, and confirmed by multiple observations, that disks around low-mass stars display a molecule-rich emission and carbon-rich disk chemistry as compared to their hotter, more massive solar counterparts. In this work, we present JWST Disk Infrared Spectral Chemistry Survey MIRI-MRS observations of the solar-mass star DoAr 33, a low-accretion rate T Tauri star showing an exceptional carbon-rich inner disk. We report detections of H2O, OH, and CO2, as well as the more complex hydrocarbons, C2H2 and C4H2. Through the use of thermochemical models, we explore different spatial distributions of carbon and oxygen across the inner disk and compare the column densities and temperatures obtained from LTE slab model retrievals. We find the best match to the observed column densities with models that have carbon enrichment, and the retrieved emitting temperature and area of C2H2 with models that have C/O = 2–4 inside the 500 K carbon-rich dust sublimation line. This suggests that the origin of the carbon-rich chemistry is likely due to the sublimation of carbon-rich grains near the soot line. This would be consistent with the presence of dust processing as indicated by the detection of crystalline silicates. We propose that this long-lived hydrocarbon-rich chemistry observed around a solar-mass star is a consequence of the unusually low M-star-like accretion rate of the central star, which lengthens the radial mixing timescale of the inner disk, allowing the chemistry powered by carbon grain destruction to linger.
JWST/MIRI Detection of a Carbon-rich Chemistry in the Disk of a Solar Nebula Analog
- Creators
-
Colmenares, María José1
-
Bergin, Edwin A.1
-
Salyk, Colette2
-
Pontoppidan, Klaus M.3, 4
-
Arulanantham, Nicole5
-
Calahan, Jenny6
-
Banzatti, Andrea7
-
Andrews, Sean6
-
Blake, Geoffrey A.4
-
Ciesla, Fred8
-
Green, Joel5
-
Long 龙, Feng 凤9
-
Lambrechts, Michiel10
-
Najita, Joan11
-
Pascucci, Ilaria9
-
Pinilla, Paola12
-
Krijt, Sebastiaan13
-
Trapman, Leon14
- JDISCS Collaboration
-
1.
University of Michigan–Ann Arbor
-
2.
Vassar College
-
3.
Jet Propulsion Lab
-
4.
California Institute of Technology
-
5.
Space Telescope Science Institute
-
6.
Harvard-Smithsonian Center for Astrophysics
-
7.
Texas State University
-
8.
University of Chicago
-
9.
University of Arizona
-
10.
University of Copenhagen
-
11.
NOIRLab
-
12.
University College London
-
13.
University of Exeter
-
14.
University of Wisconsin–Madison
Abstract
Copyright and License
© 2024. The Author(s). Published by the American Astronomical Society.
Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
Acknowledgement
We thank the referee for the insightful comments, which helped improve the quality of this paper. We thank John Black for providing the LAMDA file of C2H2 spectroscopy used in the thermochemical models. M.J.C. and E.A.B. acknowledge funding from NASA's Exoplanet Research Program, grant 80NSSC20K0259. E.A.B. acknowledges support from NSF grant No. 1907653 and NASA's Emerging Worlds Program, grant 80NSSC20K0333. This work is based on observations made with the NASA/ESA/CSA James Webb Space Telescope. The specific observations analyzed can be accessed via doi:10.17909/1ca9-gp84. The data were obtained from the Mikulski Archive for Space Telescopes at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-03127 for JWST. A portion of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (80NM0018D0004).
Facilities
JWST - James Webb Space Telescope.
Software References
astropy (Astropy Collaboration et al. 2013, 2018, 2022), spectools-ir (C. Salyk 2022), iSLAT (E. Jellison et al. 2024; M. Johnson et al. 2024), RADMC-3D (C. P. Dullemond et al. 2012).
Files
Name | Size | Download all |
---|---|---|
md5:71c33afabc4df56047e75999bdec1aff
|
3.7 MB | Preview Download |
Additional details
- National Aeronautics and Space Administration
- 80NSSC20K0259
- National Science Foundation
- AST-1907653
- National Aeronautics and Space Administration
- 80NSSC20K0333
- National Aeronautics and Space Administration
- NAS 5-03127
- National Aeronautics and Space Administration
- 80NM0018D0004
- National Aeronautics and Space Administration
- NASA Hubble Fellowship Program Sagan Fellowship
- Accepted
-
2024-10-23Accepted
- Available
-
2024-12-11Published
- Caltech groups
- Division of Geological and Planetary Sciences
- Publication Status
- Published