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Related papers: Inflow Motions associated with High-mass Protostel…

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A plausible model is proposed for the enhancement of the abundance of molecular species in bipolar outflow sources. In this model, levels of HCO+ enhancement are considered based on previous chemical calculations, that are assumed to result…

Astrophysics · Physics 2009-11-10 J. M. C Rawlings , M. P. Redman , E. Keto , D. A. Williams

As natural consequences of the accretion process, outflows are one of the few (indirect) tracers of accretion. We used CO(2-1) PdBI observations towards 6 MDCs in Cygnus-X, containing 9 high-mass cores, to investigate what the accretion…

Astrophysics of Galaxies · Physics 2015-06-17 A. Duarte-Cabral , S. Bontemps , F. Motte , M. Hennemann , N. Schneider , Ph. Andre

We present the detection of kinematic infall signatures towards the Class 0 protostellar system SMM4 in the Serpens cloud core. We have observed the dense molecular gas towards the embedded source using millimeter and submillimeter line…

Astrophysics · Physics 2009-11-07 G. Narayanan , G. Moriarty-Schieven , C. K. Walker , H. M. Butner

Aims. Studying protostellar objects in their earliest stages, particularly during the Class 0 phase, provides key insight into the beginnings of planet formation and dust evolution. Disentangling the various components, however, is…

We present multi-line and continuum observations of the circumstellar environment within 10^4 AU of a sample of protostars to investigate how the effects of outflows on their immediate environment changes over time. 12CO(1-0) emission…

Astrophysics · Physics 2008-11-26 Hector G. Arce , Anneila I. Sargent

We present Submillimeter Array observations toward the 10^{4.7} Lsun star-forming region G240.31+0.07, in the J=2-1 transition of 12CO and 13CO and at 1.3 mm continuum, as well as the 12CO and 13CO observations from the Caltech…

Astrophysics of Galaxies · Physics 2011-02-11 Keping Qiu , Qizhou Zhang , Jingwen Wu , Huei-Ru Chen

Intermediate mass protostarsprovide a bridge between theories of low- and high-mass star formation. Emerging molecular outflows can be used to determine the influence of fragmentation and multiplicity on protostellar evolution through the…

We present Submillimeter Array (SMA) observations of the HCN\,(3--2) and HCO$^+$\,(3--2) molecular lines toward the W3(H$_2$O) and W3(OH) star-forming complexes. Infall and outflow motions in the W3(H$_2$O) have been characterized by…

Solar and Stellar Astrophysics · Physics 2016-01-27 Sheng-Li Qin , Peter Schilke , Jingwen Wu , Tie Liu , Yuefang Wu , Álvaro Sánchez-Monge , Ying Liu

We observe 1.3~mm spectral lines at 2000~AU resolution toward four massive molecular clouds in the Central Molecular Zone of the Galaxy to investigate their star formation activities. We focus on several potential shock tracers that are…

This paper presents a large spectral line and continuum survey of 8 deeply embedded, low-mass protostellar cores using the Submillimeter Array. Each source was observed in high excitation lines of some of the most common molecular species,…

Observations of dense molecular gas lie at the basis of our understanding of the density and temperature structure of protostellar envelopes and molecular outflows. We aim to characterize the properties of the protostellar envelope,…

Solar and Stellar Astrophysics · Physics 2015-05-14 T. A. van Kempen , E. F. van Dishoeck , M. R. Hogerheijde , R. Guesten

The research of infall motion is a common means to study molecular cloud dynamics and the early process of star formation. Many works had been done in-depth research on infall. We searched the literature related to infall study of molecular…

Astrophysics of Galaxies · Physics 2022-09-14 Shuling Yu , Zhibo Jiang , Yang Yang , Zhiwei Chen , Haoran Feng

This paper presents the first substantial study of the chemistry of the envelopes around a sample of 18 low-mass pre- and protostellar objects for which physical properties have previously been derived from radiative transfer modeling of…

Astrophysics · Physics 2009-11-10 J. K. Jorgensen , F. L. Schoeier , E. F. van Dishoeck

With the aim of understanding the role of outflows in star formation, we performed a statistical study of the physical parameters of outflows in eleven massive protoclusters associated with ultra-compact HII regions. A total of 106 outflow…

Some theoretical models propose that O-B stars form via accretion, in a similar fashion to low-mass stars. Jet-driven molecular outflows play an important role in this scenario, and their study can help to understand the process of…

Recent Galactic plane surveys of dust continuum emission at long wavelengths have identified a population of dense, massive clumps with no evidence for on-going star formation. These massive starless clump candidates are excellent sites to…

During the early stages of star formation, accretion processes such as infall from the envelope and molecular streamers, and ejection of matter through winds and jets take place simultaneously. The Class 0/I binary [BHB2007] 11 shows…

We report single-dish multi-transition measurements of the 12^CO, HCN, and HCO^+ molecular line emission as well as HNC J=1-0 and HNCO in the two ultraluminous infra-red galaxies Arp220 and NGC6240. Using this new molecular line inventory,…

Astrophysics · Physics 2009-03-27 T. R. Greve , P. P. Papadopoulos , Y. Gao , S. J. E. Radford

(abridged) We study a previously discovered protostellar source that is deeply embedded and drives an energetic molecular outflow. The source, UYSO1, is located close to IRAS 07029-1215 at a distance of ~1 kpc. The multi-wavelength…

How high-mass stars form remains unclear currently. Calculation suggests that the radiation pressure of a forming star can halt spherical infall, preventing its further growth when it reaches 10 M$_{\odot}$. Two major theoretical models on…

Solar and Stellar Astrophysics · Physics 2014-11-04 Yuefang Wu , Tie Liu , Shengli Qin