Details

Autor(en) / Beteiligte

• Yen, Hsi-Wei
• Takakuwa, Shigehisa
• OHASHI, NAGAYOSHI
• Ho, Paul T P

Titel

UNVEILING THE EVOLUTIONARY SEQUENCE FROM INFALLING ENVELOPES TO KEPLERIAN DISKS AROUND LOW-MASS PROTOSTARS

Ist Teil von

• The Astrophysical journal, 2013-07, Vol.772 (1), p.1-25

Ort / Verlag

United States

Erscheinungsjahr

2013

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• We performed Submillimeter Array observations in the C super(18)O(2-1) emission line toward six Class 0 and I protostars to study rotational motions of their surrounding envelopes and circumstellar material on 100-1000 AU scales. C super(18)O (2-1) emission with intensity peaks located at the protostellar positions is detected toward all six sources. The rotational velocities of the protostellar envelopes as a function of radius were measured from the position-velocity diagrams perpendicular to the outflow directions passing through the protostellar positions. Two Class 0 sources, B335 and NGC 1333 IRAS 4B, show no detectable rotational motion, while L1527 IRS (Class 0/I) and L1448-mm (Class 0) exhibit rotational motions with radial profiles of V sub(rot) [is proportional to] r super(-1.0+ or -0.2) and [is proportional to] r super(-1.0+ or -0.1), respectively. The other Class I sources, TMC-1A and L1489 IRS, exhibit the fastest rotational motions among the sample, and their rotational motions have flatter radial profiles of V sub(rot) [is proportional to] r super(-0.6+ or -0.1) and [is proportional to] r super(-0.5+ or -0.1), respectively. The rotational motions with the radial dependence of ~r super(-1) can be interpreted as rotation with a conserved angular momentum in a dynamically infalling envelope, while those with the radial dependence of ~r super(-0.5) can be interpreted as Keplerian rotation. These observational results demonstrate categorization of rotational motions from infalling envelopes to Keplerian-disk formation. Models of the inside-out collapse where the angular momentum is conserved are discussed and compared with our observational results.