Dynamical structure of the inner 100 AU of the deeply embedded protostar IRAS 16293-2422

Abstract

A fundamental question about the early evolution of low-mass protostars is when circumstellar disks may form. High angular resolution observations of molecular transitions in the (sub)millimeter wavelength windows make it possible to investigate the kinematics of the gas around newly-formed stars, for example to identify the presence of rotation and infall. IRAS 16293-2422 was observed with the extended Submillimeter Array (eSMA) resulting in subarcsecond resolution (0.46" x 0.29", i.e. $\sim$ 55 $\times$ 35~AU) images of compact emission from the C${}^{17}$O (3-2) and C${}^{34}$S (7-6) transitions at 337~GHz (0.89~mm). To recover the more extended emission we have combined the eSMA data with SMA observations of the same molecules. The emission of C${}^{17}$O (3-2) and C${}^{34}$S (7-6) both show a velocity gradient oriented along a northeast-southwest direction with respect to the continuum marking the location of one of the components of the binary, IRAS16293A. Our combined eSMA and SMA observations show that the velocity field on the 50--400~AU scales is consistent with a rotating structure. It cannot be explained by simple Keplerian rotation around a single point mass but rather needs to take into account the enclosed envelope mass at the radii where the observed lines are excited. We suggest that IRAS 16293-2422 could be among the best candidates to observe a pseudo-disk with future high angular resolution observations.

Accepted for publication in ApJ, 18 pages, 10 figures

References in corpus (4)

• An interferometric study of the low-mass protostar IRAS 16293-2422: small scale organic chemistry
• SMA observations of young disks: separating envelope, disk, and stellar masses in class I YSOs
• The CO Molecular Outflows of IRAS 16293-2422 Probed by the Submillimeter Array
• The eSMA: description and first results

Cited by in corpus (10)

• The ALMA Protostellar Interferometric Line Survey (PILS): First results from an unbiased submillimeter wavelength line survey of the Class 0 protostellar binary IRAS 16293-2422 with ALMA
• L483: Warm Carbon-Chain Chemistry Source Harboring Hot Corino Activity
• The properties of discs around planets and brown dwarfs as evidence for disc fragmentation
• Dust Polarization Toward Embedded Protostars in Ophiuchus with ALMA. II. IRAS 16293-2422
• The ALMA-PILS survey: Gas dynamics in IRAS 16293$-$2422 and the connection between its two protostars
• An unbiased spectral line survey observation toward the low-mass star-forming region L1527
• Temperature profiles of young disk-like structures: The case of IRAS 16293A
• Dust hot spots at 10 au scales around the Class 0 binary IRAS 16293-2422 A: a departure from the passive irradiation model
• The dynamical evolution of low-mass hydrogen-burning stars, brown dwarfs and planetary-mass objects formed through disc fragmentation
• Rotating Motion of the Outflow of IRAS 16293-2422 A1 at its Origin Point near the Protostar