اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدALMA detects a radial disk wind in DG Tau
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تأليف
M. Guedel
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Aims: We aim to use the high spatial resolution of the Atacama Large Millimeter/submillimeter Array (ALMA) to map the flow pattern of molecular gas near DG Tau and its disk, a young stellar object driving a jet and a molecular outflow. Methods: We use observations from ALMA in the J = 2 - 1 transition of 12CO, 13CO, and C18O to study the Keplerian disk of DG Tau and outflows that may be related to the disk and the jet. Results: We find a new wind component flowing radially at a steep angle (~25 deg from the vertical) above the disk with a velocity of ~ 3.1 km/s. It continues the trend of decreasing velocity for increasing distance from the jet axis (onion-like velocity structure). Conclusions: The new component is located close to the protostellar disk surface and may be related to photoevaporative winds.
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We present Atacama Large Millimeter Array (ALMA) Band 6 observations at 14-20 au spatial resolution of the disk and CO(2-1) outflow around the Class I protostar DG Tau B in Taurus. The disk is very large, both in dust continuum (R$_{rm eff,95%}$=174
au) and CO (R$_{CO}$=700 au). It shows Keplerian rotation around a 1.1$pm$0.2 M$_{odot}$ central star and two dust emission bumps at $r$ = 62 and 135 au. These results confirm that large structured disks can form at an early stage where residual infall is still ongoing. The redshifted CO outflow at high velocity shows a striking hollow cone morphology out to 3000 au with a shear-like velocity structure within the cone walls. These walls coincide with the scattered light cavity, and they appear to be rooted within $<$ 60 au in the disk. We confirm their global average rotation in the same sense as the disk, with a specific angular momentum $simeq$ 65 au kms. The mass-flux rate of 1.7-2.9 $times$ 10$^{-7}$M$_{odot}$ yr$^{-1}$ is 35$pm$10 times that in the atomic jet. We also detect a wider and slower outflow component surrounding this inner conical flow, which also rotates in the same direction as the disk. Our ALMA observations therefore demonstrate that the inner cone walls, and the associated scattered light cavity, do not trace the interface with infalling material, which is shown to be confined to much wider angles ($> 70^{circ}$). The properties of the conical walls are suggestive of the interaction between an episodic inner jet or wind with an outer disk wind, or of a massive disk wind originating from 2-5 au. However, further modeling is required to establish their origin. In either case, such massive outflow may significantly affect the disk structure and evolution.
Water is key in the evolution of protoplanetary disks and the formation of comets and icy/water planets. While high excitation water lines originating in the hot inner disk have been detected in several T Tauri stars (TTSs), water vapor from the oute
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