Universität zu Köln

van der Wiel, M. H. D., Jacobsen, S. K., Jorgensen, J. K., Bourke, T. L., Kristensen, L. E., Bjerkeli, P., Murillo, N. M., Calcutt, H., Mueller, H. S. P., Coutens, A., Drozdovskaya, M. N., Favre, C. and Wampfler, S. F. (2019). The ALMA-PILS survey: gas dynamics in IRAS 16293-2422 and the connection between its two protostars. Astron. Astrophys., 626. LES ULIS CEDEX A: EDP SCIENCES S A. ISSN 1432-0746

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Abstract

Context. The majority of stars form in binary or higher order systems. The evolution of each protostar in a multiple system may start at different times and may progress differently. The Class 0 protostellar system IRAS 16293-2422 contains two protostars, A and B, separated by similar to 600 au and embedded in a single, 10(4) au scale envelope. Their relative evolutionary stages have been debated. Aims. We aim to study the relation and interplay between the two protostars A and B at spatial scales of 60 au up to similar to 10(3) au. Methods. We selected molecular gas line transitions of the species CO, H2CO, HCN, CS, SiO, and C2H from the ALMA-PILS spectral imaging survey (329-363 GHz) and used them as tracers of kinematics, density, and temperature in the IRAS 16293-2422 system. The angular resolution of the PILS data set allows us to study these quantities at a resolution of 0.5 '' (60 au at the distance of the source). Results. Line-of-sight velocity maps of both optically thick and optically thin molecular lines reveal: (i) new manifestations of previously known outflows emanating from protostar A; (ii) a kinematically quiescent bridge of dust and gas spanning between the two protostars, with an inferred density between 4 x 10(4) cm(-3) and similar to 3 x 10(7) cm(-3); and (iii) a separate, straight filament seemingly connected to protostar B seen only in C2H, with a flat kinematic signature. Signs of various outflows, all emanating from source A, are evidence of high-density and warmer gas; none of them coincide spatially and kinematically with the bridge. Conclusions. We hypothesize that the bridge arc is a remnant of filamentary substructure in the protostellar envelope material from which protostellar sources A and B have formed. One particular morphological structure appears to be due to outflowing gas impacting the quiescent bridge material. The continuing lack of clear outflow signatures unambiguously associated to protostar B and the vertically extended shape derived for its disk-like structure lead us to conclude that source B may be in an earlier evolutionary stage than source A.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code van der Wiel, M. H. D. UNSPECIFIED UNSPECIFIED UNSPECIFIED Jacobsen, S. K. UNSPECIFIED UNSPECIFIED UNSPECIFIED Jorgensen, J. K. UNSPECIFIED UNSPECIFIED UNSPECIFIED Bourke, T. L. UNSPECIFIED UNSPECIFIED UNSPECIFIED Kristensen, L. E. UNSPECIFIED UNSPECIFIED UNSPECIFIED Bjerkeli, P. UNSPECIFIED UNSPECIFIED UNSPECIFIED Murillo, N. M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Calcutt, H. UNSPECIFIED UNSPECIFIED UNSPECIFIED Mueller, H. S. P. UNSPECIFIED UNSPECIFIED UNSPECIFIED Coutens, A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Drozdovskaya, M. N. UNSPECIFIED UNSPECIFIED UNSPECIFIED Favre, C. UNSPECIFIED UNSPECIFIED UNSPECIFIED Wampfler, S. F. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-137593
DOI:	10.1051/0004-6361/201833695
Journal or Publication Title:	Astron. Astrophys.
Volume:	626
Date:	2019
Publisher:	EDP SCIENCES S A
Place of Publication:	LES ULIS CEDEX A
ISSN:	1432-0746
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language SIO LINE EMISSION; LOW-MASS; ROTATIONAL-EXCITATION; MOLECULAR OUTFLOWS; INTERSTELLAR JETS; HOT CORE; PROTOSTELLAR; SYSTEM; IRAS-16293-2422; COLLISIONS Multiple languages Astronomy & Astrophysics Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/13759