MINDS. A multi-instrument investigation into the molecule-rich JWST-MIRI spectrum of the DF Tau binary system
Creators: name: Grant, Sierra L.
name: Kurtovic, Nicolas T.
name: van Dishoeck, Ewine F.
name: Henning, Thomas
name: Kamp, Inga
name: Nowacki, Hugo
name: Perraut, Karine
name: Banzatti, Andrea
name: Temmink, Milou
name: Christiaens, Valentin
name: Samland, Matthias
name: Gasman, Danny
name: Tabone, Benoît
name: Güdel, Manuel
name: Lagage, Pierre-Olivier
name: Arabhavi, Aditya M.
name: Barrado, David
name: Garatti, Alessio Caratti o
name: Glauser, Adrian M.
name: Jang, Hyerin
name: Kanwar, Jayatee
name: Lahuis, Fred
name: Morales-Calderón, Maria
name: Olofsson, Göran
name: Perotti, Giulia
name: Schwarz, Kamber
name: Vlasblom, Marissa
name: Lopez, Rebeca Garcia
name: Long, Feng
Publisher: name: arXiv
Year: 2024
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: Most stars form in multiple systems whose properties can significantly impact circumstellar disk evolution. We investigate the physical and chemical properties of the equal-mass, small separation (~66 mas, ~9 au) DF Tau binary system. Previous observations indicated that only DF Tau A has a circumstellar disk. We present JWST-MIRI MRS observations of DF Tau. The MIRI spectrum shows a forest of H2O lines and emission from CO, C2H2, HCN, CO2, and OH. LTE slab models are used to determine the properties of the gas, and we analyze high angular spatial and spectral resolution data from ALMA, VLTI-GRAVITY, and IRTF-iSHELL to aid in the interpretation of the JWST data. The 1.3 mm ALMA continuum data show two equal-brightness sources of compact (R&lt;3 au) emission, with separations and movement consistent with astrometry from VLTI-GRAVITY and the known orbit. This is interpreted as a robust detection of a disk around DF Tau B, which we suggest may host a small (~1 au) cavity to reconcile all observations. The disk around DF Tau A is expected to be a full disk, and spatially and spectrally resolved dust and gas emission points to hot, close-in (&lt;0.2 au) material. Hot (~500-1000 K) H2O, HCN, and C2H2 emission in the MIRI data likely originate in the DF Tau A disk, while a cold (&lt;200 K) H2O component with an extended emitting area is consistent with an origin from both disks. Despite the very compact outer disks, the inner disk composition and conditions are similar to isolated systems, suggesting that the close binary nature is not a driving factor in setting the inner disk chemistry. However, constraining the geometry of the disks, for instance, via higher resolution ALMA observations, would provide additional insight into the mid-infrared gas emission. JWST observations of spatially resolved binaries will be important for understanding the impact of binarity on inner disk chemistry more generally.
description: Accepted to A&amp;A on June 15th, 2024. Calibrated ALMA data are available at https://zenodo.org/records/11215003. Reduced JWST-MIRI MRS spectra will be available at Spexodisks.com and available by request to the corresponding author