Dusty Disks
- Infrared spectrum reveals nature of dust in disk
- Spectra of comet Hale-Bopp cf. ? Pic vu-graph
- features at 10,000 and 20,000 nm
- resonance of small silicate particles (Mg,Fe)SiO4
- sharp structure implies crystalline state
- 10,000 nm feature in ? Pic very similar to Hale-Bopp
- dust is similar (chemical composition, size, crystallinity)
- Dust can also be seen via scattered starlight
- same way we can see comets
- Use “coronagraph” to block direct starlight
- image clearly shows elongated structure fig.20-3
- since material is in orbit around star, we are seeing disk nearly edge-on
- Hubble image shows more detail
- slight distortion (“warp”) of inner region
- caused by orbiting planet?