Complex structure of a proto-brown dwarf

Riaz, B. und Machida, M. N. (2021): Complex structure of a proto-brown dwarf. In: Monthly Notices of the Royal Astronomical Society, Bd. 504, Nr. 4: S. 6049-6066

Abstract

We present ALMA (CO)-C-12 (2-1),(CO)-C-13 (2-1), (CO)-O-18 (2-1) molecular line observations of a very young proto-brown dwarf system, ISO-OPH 200. We have conducted physical+chemical modelling of the complex internal structure for this system using the core collapse simulations for brown dwarf formation. The model at an age of similar to 6000 yr can provide a good fit to the observed kinematics, spectra, and reproduce the complex structures seen in the moment maps. Results from modelling indicate that (CO)-C-12 emission is tracing an extended (1000 Au) molecular outflow and a bright shock knot, (CO)-C-13 is tracing the outer (similar to 1000 AU) envelope/pseudo-disc, and (CO)-O-18 is tracing the inner (similar to 500 Au) pseudo-disc. The source size of similar to 8.6 AU measured in the 873-mu m image is comparable to the inner Keplerian disc size predicted by the model. A 3D model structure of ISO-OPH 200 suggests that this system is viewed partially through a wide outflow cavity resulting in a direct view of the outflow and a partial view of the envelope/pseudo-disc. We have argued that ISO-OPH 200 has been mis-classified as a Class Flat object due to the unusual orientation. The various signatures of this system, notably, the young similar to 616-yr outflow dynamical age and high outflow rate (similar to 1 x 10(-7) M-circle dot yr(-1)), silicate absorption in the 10-mu m mid-infrared spectrum, pristine ISM-like dust in the envelope/disc, comparable sizes of the extended envelope and outflow, indicate that ISO-OPH 200 is an early Class 0 stage system formed in a star-like mechanism via gravitational collapse of a very low mass core.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Physik
• Themengebiete: 500 Naturwissenschaften und Mathematik > 530 Physik
• ISSN: 0035-8711
• Sprache: Englisch