Observational Properties of Protoplanetary Disks

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1 Observational Properties of Protoplanetary Disks Leonardo Testi - ESO/Arcetri ltesti@eso.org; lt@arcetri.astro.it Today: Tracing water, deuteration and link with Solar System Complex Organic Molecule Transition disks

2 Questions from this morning CO Snowlines: why are so hard to see? Close to the star and traced by *faint* molecules! Need ALMA sensitivity! We can observe directly only gas-phase molecules How can we probe the cold midplane gas? Need molecules that do not condense on the grains (hard/faint) Moderate desorption due to CR&induced UV possible

3 Part X Water and Complex Molecules

4 (van Dishoeck+2014) The complex chemistry of YSOs and disks Tracing water in protostars and disks

5 (Ceccarelli+2014) Deuteration Systematic difference between HD, HDO and other molecules Need resolved measurements (Ceccarelli+2014)

6 Models of Deuteration in Disks (Cleeves+2014) Disk is not capable to produce the deuteration => ices

7 Can we detect water with ALMA in disks? (Brinch et al. 2010) è Herschel detects much less water than originally expected in protoplanetary disks è Freeze out and dust settling expose only a tiny fraction of the water ice to stellar radiation è Deuterium fractionation and water isotopes accessible! (Hogerheijde et al. 2011)

8 Chemical complexity (van Dishoeck 2013) Complex molecules are formed on the ices and then can be released in the gas phase as ices sublimate

9 Chemical complexity Climbing the ladder of chemical complexity

10 Hot molecular cores (Sanchez-Monge+2014) This process is commonly observed in hot molecular cores where young massive stars evaporate the icy mantles

11 Chemical complexity (Jorgensen+2012) Simple sugar (glycolaldehyde) in low mass protostar

12 Chemical complexity - Future (Belloche+2014) (van der Marel+2014) H2CO (Jimenez-Serra+2014) Full ALMA sensitivity required Very hard to detect complex molecules in disks

13 5 min pause How can we explain the radial distribution of [D]/ [H] in our own Solar System? Are we focusing too much on a chemistry of life tuned on what we have on Earth? What about chirality?

14 Take home points Molecular spectroscopy is potentially a very powerful tool to study disk kinematics, physics and chemistry Complex modelling Missing/uncertain key data: collision rates, reaction rates ALMA will be the prime tool to study gas in disks kinematics, physics and chemistry of disks The Chemical heritage of the Solar System may be linked to a pre-disk evolution

15 Part XI Transitional Disks and Disk Dissipation

16 What if we carve a hole? νf ν ν (4q-2)/q ν 3+ β νf ν λ λ

17 Transition disks Williams&Cieza2011 ~10-20% of disk population, likely represent a variety of evolutionary patterns

18 Transition disks Lack of dust opacity in the inner disk Grain growth? Photoevaporated hole Dynamically carved hole

19 Grain properties in TDs Fast! Early growth in protostars Evolution??? (Pinilla et al. 2014)

20 Disk photoevaporation (Armitage) Energetic stellar radiation heats the disk surface Unbound material flows away from the system

21 Fast removal of inner disk EUV+FUV+X-rays (Gorti+2009) Outer disk inflow maintains inner disk, when Macc fades a gap is created and the inner disk is removed

22 Evidence of photoevaporation (Pascucci+2011) Blueshifted [NeII] line from the wind

23 (Alexander+2014) Scenario

24 Dust depleted inner regions (Andrews+2011) mm continuum images reveal inner cavity

25 (Rosotti+2013) Accretion in TDs Accretion phase should be very short

26 (Manara+2014) Accretion in TDs There is a relatively large population of TDs with large inner holes that show accretion compatible with classical disks

27 ALMA results on TDs (Perez+2015)

28 ALMA results on TDs (Fukagawa+2013) (Perez+2014) Vortices or planet-induced azimuthal asymmetries in the gas distribution that lead to particle confinement

29 Take home points Photoevaporation alone has troubles in explaining transition disks Especially the accreting disks with large inner holes A combination of various effects may conspire to explain the characteristics of transition disks Combination of planet formation and photoevaporation? ALMA reveals asymmetries in the large grains distribution in the outer disk may promote formation of large bodies in the outer disk