VLA Imaging of the Disk Surrounding the Nearby Young Star TW Hydrae

摘要: The TW Hya system is perhaps the closest analog to early solar nebula. We have used Very Large Array image at wavelengths of 7mm and 3.6 cm with resolutions 0.1 arcseconds (about 5 AU) 1.0 50 AU), respectively. emission extended appears dominated by a dusty disk radius larger than AU surrounding star. unresolved likely arises from an ionized wind or gyrosynchrotron activity. dust spectrum spatially resolved images are fitted simple model temperature surface density described radial power laws, $T(r)\propto r^{-0.5}$ $\Sigma(r) \propto r^{-1}$. These properties consistent irradiated gaseous accretion mass $\sim0.03~{\rm M_{\odot}}$ rate $\sim10^{-8}~{\rm M_{\odot}yr^{-1}}$ viscosity parameter $\alpha = 0.01$. estimates rates uncertain as gas-to-dust ratio in may evolved standard interstellar value.