In section 10. Planets and planetary systems
The circumstellar disk of HH 30
With its edge-on circumstellar disk and prominent, rapidly variable jet, HH30 has been an icon of astronomy since its discovery in the 1990s. Madlener et al. reexamine the structure of this object using high-resolution imaging, the spectral energy distribution from the millimeter to the infrared, and a Markov chain Monte Carlo approach. They conclude that the disk must have an inner region with a radius of ~45 AU that is depleted in dust, and an outer region that contains most of the mass of the disk and extends to ~140 AU. In that outer region, grains must have grown to millimeter sizes. Beyond 140 AU and up to maybe ~400 AU the disks is detected in the infrared but not at millimeter wavelength, indicating that the grains are probably smaller and presumably less abundant. Additional observations with most importantly ALMA and JWST combined with a more complex modeling that includes vertical and radial variations of dust properties will greatly increase our knowledge of this fascinating object.