Circumbinary and circumstellar discs around the eccentric binary IRAS 04158+2805 - a testbed for binary-disc interaction Autori: E. Ragusa et al.

Monday 30 May 2022, 13:50 → 14:10 Europe/Rome

0/0-3 - Sala Rosino (Dipartimento di Fisica e Astronomia - Edificio ex-Rizzato)

Speakers: Andrea Bolamperti (Università degli Studi di Padova)

IRAS 04158+2805 has long been thought to be a very low mass T-Tauri star (VLMS) sur-rounded by a nearly edge-on, extremely large disc. Recent observations revealed that thissource hosts a binary surrounded by an extended circumbinary disc with a central dust cavity.In this paper, we combine ALMA multi-wavelength observations of continuum and12CO lineemission, with H𝛼imaging and Keck astrometric measures of the binary to develop a coherentdynamical model of this system. The system features an azimuthal asymmetry detected at thewestern edge of the cavity in Band 7 observations and a wiggling outflow. Dust emission inALMA Band 4 from the proximity of the individual stars suggests the presence of marginallyresolved circumstellar discs. We estimate the binary orbital parameters from the measuredarc of the orbit from Keck and ALMA astrometry. We further constrain these estimates usingconsiderations from binary-disc interaction theory. We finally perform three SPH gas + dustsimulations based on the theoretical constraints; we post-process the hydrodynamic output us-ing radiative transfer Monte Carlo methods and directly compare the models with observations.Our results suggest that a highly eccentric𝑒?0•5–0•7equal mass binary, with a semi-majoraxis of?55au, and small/moderate orbital plane vs. circumbinary disc inclination𝜃.30?provides a good match with observations. A dust mass of?1•5?104Mbest reproduces theflux in Band 7 continuum observations. Synthetic CO line emission maps qualitatively captureboth the emission from the central region and the non-Keplerian nature of the gas motion inthe binary proximity.

2107.13566.pdf

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