1. Why is water interesting? Evidence of water in space Water in young disks Water in the terrestrial planet-forming zone Future prospects Water in young planet-forming disks

2. Major constituent of dust grains One of the most abundant molecules Dominant form of Oxygen in space Important cloud coolant Major constituent of comets Oceans on Terrestrial planets Makes telescopes 10-100X more expensive Why is water interesting? (VLT, B68) (NASA/Phoenix)

3. Water sources Mainly evolved stars: Planetary Nebulae, supergiants, etc eg VY Cma (supergiant, at 1kpc) (Herschel/PACS: Decin & Barlow, 2009) => total mass loss rate 10 -4 Msun/year, of which, 0.1% is H 2 O (~0.5 Mars mass/year)

4. Energy levels Complex spectra: Rotation Symmetric stretch Asymmetric stretch Bending vibration + ortho/para modes J (K a,K c ) (v1,v2,v3) => many millions of transitions (eg Barber et al 2006 has 505,806,202)

5. Evidence of water in space From the ground: 22GHz maser lines ( 6(1,6) – 5(2,3)) Sub-mm lines (eg 3(1,3) – 2(2,0) of H 2 18 O at 203GHz (maser?) Near-infrared lines (3.9μm and 2.2μm) Near-infrared ice features (3.1μm) Satellites open up many opportunities for brighter lines and lower energy levels: Mid-infrared (IRAS, Spitzer) Far-infrared (ISO, Herschel)

6. Evidence of water in space 22GHz masers: peculiar conditions, shocks, outflows.. Mid-infrared: hot water (1000K+) (Desmurs et al, 2009; Salyk et al, 2009)

7. Water in young disks – a near infrared survey H 2 O 13(4,10)– 12(2,11) CO bandhead

8. Constant line/continuum ratio Line ratio T = 500K 1000K 1500K (1) Water emission is ubiquitous (2) Emitting gas is warm (500-800K) Linewidths 20-30km/s (3) few AU radii Results from near-ir survey

9. Cooler water 3(2,2)-2(1,1) 2(1,2)-1(0,1) 2(2,1)-2(1,2) 115K 194K297K Herschel – PACS far-ir spectral survey of young disks: water detected in some

10. Where is the water in disks? Radius of snowline strongly depends on Z Models: snowline is actually ~parallel to the disk plane in the planet-forming region (r=1-10AU) (Meijerink et al., 2010; Thi et al., 2010) H2O abundance

11. Summary and future water studies H 2 O observations of 100-500K gas now possible H 2 O is ubiquitous in young disks Snowline is horizontal, not vertical In next 1-5 years: Herschel HIFI (heterodyne spectrometer) ALMA band 5 (183 and 203GHz) SOFIA (747-mounted 2.5m telescope) ELT and high-resolution spectrometers (SPICA - 3.5m space telescope, cooled to 4K) Improved modelling techniques