Younger disks -- gas and dust
Even younger HH 30 Fig. 20-4
- Star is hidden by dusty disk surrounding it
- can see starlight reflecting above and below disk
- “jets” indicate bi-polar outflows
- first stage of T-Tauri wind
- stage c) of Fig. 7
- Eventually, this wind will “clear out” the nebula
- after planets form
- ? Pic disk has no gas
~ 106 y old Disks revealed in Orion Nebula
- Very bright and hot stars of the Trapezium
- ionize and excite the diffuse Nebular gas
- provides a luminous backdrop
- dusty disk seen as darkening Fig. 20-5
- embedded star seen in scattered light below and above
- disk diameter 17 times diameter Pluto’s orbit
- plenty of material for eventual planet formation