Molecular Line Observations of the Small Protostellar Group L1251B

Abstract

We present molecular line observations of L1251B, a small group of pre- and protostellar objects, and its immediate environment in the dense C18O core L1251E. These data are complementary to near-infrared, submillimeter and millimeter continuum observations reported by Lee et al. (2006, ApJ, 648, 491; Paper I). The single-dish data of L1251B described here show very complex kinematics including infall, rotation and outflow motions, and the interferometer data reveal these in greater detail. Interferometer data of N2H+ 1-0 suggest a very rapidly rotating flattened envelope between two young stellar objects, IRS1 and IRS2. Also, interferometer data of CO 2-1 resolve the outflow associated with L1251B seen in single-dish maps into a few narrow and compact components. Furthermore, the high resolution data support recent theoretical studies of molecular depletions and enhancements that accompany the formation of protostars within dense cores. Beyond L1251B, single-dish data are also presented of a dense core located ~150" to the east that, in Paper I, was detected at 850 micron but has no associated point sources at near- and mid-infrared wavelengths. The relative brightness between molecules, which have different chemical timescales, suggests it is less chemically evolved than L1251B. This core may be a site for future star formation, however, since line profiles of HCO+, CS, and HCN show asymmetry with a stronger blue peak, which is interpreted as an infall signature.

46 pages, 18 figures. Accepted for publication in ApJ

References in corpus (21)

• Embedded Clusters in Molecular Clouds
• Dense Cores in Dark Clouds. XIV. N2H+(1-0) maps of dense cloud cores
• Tracing the Mass during Low-Mass Star Formation. II. Modelling the Submillimeter Emission from Pre-Protostellar Cores
• A Search for Infall Motions Toward Nearby Young Stellar Objects
• Molecular Evolution in Collapsing Prestellar Cores
• Evolution of Chemistry and Molecular Line Profile during Protostellar Collapse
• Infall, Outflow, Rotation, and Turbulent Motions of Dense Gas within NGC 1333 IRAS 4
• Chemistry as a probe of the structures and evolution of massive star forming regions
• Evolutionary Signatures in the Formation of Low-Mass Protostars
• Collapse and Fragmentation of Rotating Magnetized Clouds. II. Binary Formation and Fragmentation of First Cores
• The Spitzer c2d Survey of Large, Nearby, Interstellar Clouds: VI. Perseus Observed with MIPS
• Tracing the Mass during Low-Mass Star Formation, IV: Observations and Modeling of the Submillimeter Continuum Emission from Class I Protostars
• Chemistry and Dynamics in Pre-Protostellar Cores
• Models for Dense Molecular Cloud Cores
• Probing Pre-Protosellar Cores with Formaldehyde
• The HCO+ emission excess in bipolar outflows
• Imaging chemical differentiation around the low-mass protostar L483-mm
• Quiescent Dense Gas in Protostellar Clusters: the Ophiuchus A Core
• Does Infall End Before the Class I Stage?
• Modelling submillimetre spectra of the protostellar infall candidates NGC1333-IRAS2 and Serpens SMM4
• The Spitzer c2d Survey of Nearby Dense Cores: III: Low Mass Star Formation in a Small Group, L1251B

Cited by in corpus (14)

• SMA Observations of Class 0 Protostars: A High-Angular Resolution Survey of Protostellar Binary Systems
• The Spitzer survey of interstellar clouds in the Gould Belt. II. The Cepheus Flare observed with IRAC and MIPS
• Rotation of the Warm Molecular Gas Surrounding Ultracompact HII Regions
• The Initial Conditions of Clustered Star Formation. II. N2H+ Observations of the Ophiuchus B Core
• Pre-main sequence stars in the Cepheus flare region
• The Spitzer c2d Survey of Nearby Dense Cores XI : Infrared and Submillimeter Observations of CB130
• The JCMT Gould Belt Survey: First results from SCUBA-2 observations of the Cepheus Flare Region
• The Green Bank Ammonia Survey: Observations of Hierarchical Dense Gas Structures in Cepheus-L1251
• Infall and outflow detections in a massive core JCMT 18354-0649S
• The Spitzer c2d Survey of Nearby Dense Cores VII: Chemistry and Dynamics in L43
• Molecular Line Profiles from a Core Forming in a Turbulent Cloud
• A rotating helical filament in the L1251 dark cloud
• Cloud Motion and magnetic fields: Four clouds in the Cepheus Flare region
• Evidence of Accretion Burst: The Viscously Heated Inner Disk of the Embedded Protostar IRAS 16316-1540