Related papers: Observing the onset of outflow collimation in a ma…
We have carried out ALMA observations of the massive star-forming region W75N(B), which contains the massive protostars VLA1, VLA2, and VLA3. Particularly, VLA2 is an enigmatic protostar associated with a wind-driven H$_2$O maser shell,…
Several radio sources have been detected in the HMSFR W75N(B), among them the massive YSOs VLA1 and VLA2 are of great interest. These are thought to be in different evolutionary stages. In particular, VLA1 is at the early stage of the…
W75N(B) is a massive star-forming region that contains three radio continuum sources (VLA 1, VLA 2, and VLA 3), which are thought to be three massive young stellar objects at three different evolutionary stages. VLA 1 is the most evolved…
Molecular outflows in the form of wide-angle winds and/or well-collimated jets are associated with young stellar objects of all luminosities. Independent studies have established that the mass outflow rate is proportional to L_bol^0.6 for…
Star formation is ubiquitously associated with the ejection of accretion-powered outflows that carve bipolar cavities through the infalling envelope. This feedback is expected to be important for regulating the efficiency of star formation…
A debated topic in star formation theory is the role of magnetic fields during the protostellar phase of high-mass stars. It is still unclear how magnetic fields influence the formation and dynamics of massive disks and outflows. Most…
Forming massive stars launch outflows of magnetic origin, which in fact serve as a marker for finding sites of massive star formation. However, both the theoretical and observational study of the mechanisms that intervene in the formation…
We present 2" to 7" resolution 3 mm continuum and CO(J=1-0) line emission and near infrared Ks, H2, and [FeII] images toward the massive star forming region W75 N. The CO emission uncovers a complex morphology of multiple, overlapping…
We present two dimensional cylindrically symmetric hydrodynamic simulations and synthetic emission maps of a stellar wind propagating into an infalling, rotating environment. The resulting outflow morphology, collimation and stability…
We present Very Long Baseline Interferometry (VLBI) observations of 22 GHz H$_2$O masers in the high-mass star-forming region of \objectname{W75N}, carried out with VLBI Exploration of Radio Astrometry (VERA) for three-epochs in 2007 with…
Outflowing motions, whether a wind launched from the disk, a jet launched from the protostar, or the entrained molecular outflow, appear to be an ubiquitous feature of star formation. These outwards motions have a number of root causes, and…
We present wide-field near-infrared images of the DR21/W75 high-mass star forming region, obtained with the Wide Field Camera, WFCAM, on the United Kingdom Infrared Telescope. Broad-band JHK and narrow-band H2 1-0S(1) images are compared to…
We present an evolutionary sequence of models of the photoionized disk-wind outflow around forming massive stars based on the Core Accretion model. The outflow is expected to be the first structure to be ionized by the protostar and can…
Massive protostars launch accretion-powered, magnetically-collimated outflows, which play crucial roles in the dynamics and diagnostics of the star formation process. Here we calculate the shock heating and resulting free-free radio…
Magnetic stresses collimate protostellar winds into a common distribution of force with angle. Sweeping into the ambient medium, such winds drive bipolar molecular outflows whose properties are insensitive to the distribution of ambient gas…
Massive protostars attain high luminosities as they are actively accreting and the radiation pressure exerted on the gas in the star's atmosphere may launch isotropic high-velocity winds. These winds will collide with the surrounding gas…
We present five epochs of VLBI water maser observations around the massive protostar Cepheus A HW2 with 0.4 mas (0.3 AU) resolution. The main goal of these observations was to follow the evolution of the remarkable water maser…
Young stellar objects/planetary nebula outflow anisotropies usually involve wind-wind interactions and magnetic collimation, but detailed structures of wind and magnetic fields inside collimation region remain undetermined. We numerically…
Protostellar outflow is a prominent process that accompanies the formation of stars. It is generally agreed that wide-angled protostellar outflows come from the interaction between the wind from a forming star and the ambient gas. However,…
We demonstrate that magnetically-collimated protostellar winds will sweep ambient material into thin, radiative, momentum-conserving shells whose features reproduce those commonly observed in bipolar molecular outflows. We find the typical…