Cloud Formation & Dynamics in Cool Stellar & Planetary Atmospheres

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1 + Cloud Formation & Dynamics in Cool Stellar & Planetary Atmospheres Adam J. Burgasser UC San Diego/MIT

2 + Clouds are a universal characteristic of low temperature stars/brown dwarfs (particularly L dwarfs), hot exoplanets and solar planets Properties of clouds vary over many scales, both spatial & temporal; considerable diversity exists Intimate connection between dynamics & cloud formation

3 + Clouds & dynamics in ultracool dwarf atmospheres

4 Ultracool Dwarfs: What evidence for clouds? T dwarfs L dwarfs M dwarfs clouds photosphere Marley et al. (2002) see also Allard et al. (2001); Lodders (2002) e.g.: TiO TiO 2 (s), CaTiO 3 (s) VO VO(s) Fe Fe(l,s) SiO SiO 2 (s), MgSiO 3 (s)

5 Ultracool Dwarfs: What evidence for clouds? clouds w/o dust T dwarfs w/ dust (L dwarfs) Chabrier et al. (2000)

6 Ultracool Dwarfs: What evidence for clouds? clouds TiO,VO Kirkpatrick et al. (1999) See also Lodders (1999), Allard et al. (2001)

7 Ultracool Dwarfs: What evidence for clouds? clouds Cushing et al. (2008) see also Burgasser et al. (2008); Looper et al. (2008)

8 Ultracool Dwarfs: What evidence for clouds? clouds M J J-K s color Burrows et al. (2006) See also Dahn et al. (1999); Ackerman & Marley (2001); Marley et al. (2002); Tinney et al. (2003); Tsuji (2003,2005); Saumon & Marley (2008)

9 Ultracool Dwarfs: What evidence for clouds? deeper 1500 K L5 900 K T8 clouds more cloud Ackerman & Marley (2001) See also Cooper et al. (2003); Tsuji (2005); Burrows et al. (2006)

10 Ultracool Dwarfs: What evidence for clouds? clouds M J J-K s color Burrows et al. (2006) See also Dahn et al. (1999); Ackerman & Marley (2001); Marley et al. (2002); Tinney et al. (2003); Tsuji (2003,2005); Saumon & Marley (2008)

11 Ultracool Dwarfs: Cloud variations Normalized F! clouds Wavelength (!m) Data from the SpeX Prism Libraries See also Folkes et al. (2007); Burgasser et al. (2008); Looper et al. (2008)

12 Ultracool Dwarfs: Cloud variations clouds Burgasser et al. (2008) see also McLean et al. (2003); Knapp et al. (2004); Cruz et al. (2007); Cushing et al. (2008); 2009 Stephens Adam et J. al. Burgasser (2009)

13 Ultracool Dwarfs: Cloud variability clouds Artigau et al. (2009) see also Bailer-Jones et al. (1999, 2001, 2002, 2003, 2008); Clarke et al. (2002); Gelino et al. (2002); Enoch et al. (2003); Koen (2003,2004, 2005, 2006, 2008); Caballero et al. (2004); Morales-Calderon et al. (2006); Goldman et al. (2008)

14 Ultracool Dwarfs: Atmospheric dynamics clouds Data Equilibrium Mixing NH 3 mix = H 2 /K zz < chem Saumon et al. (2006,2007) see also Fegley & Lodders (1996) Noll et al. (1997); Oppenheimer et al. (1998); Griffith & Yelle (1999); Leggett et al. (2007); Hubeny & Burrows (2007); Cushing et al. (2008); Burgasser et al. (2008); Geballe et al. (2009); 2009 Stephens Adam et J. al. Burgasser (2009)

15 Ultracool Dwarfs: The L/T Transition clouds M J J-band bump J-K s color Burrows et al. (2006) See also Dahn et al. (1999); Ackerman & Marley (2001); Marley et al. (2002); Tinney et al. (2003); Tsuji (2003,2005); Saumon & Marley (2008)

16 Ultracool Dwarfs: The L/T Transition J clouds H Primary Secondary Combined Light Data K s Looper et al. (2008); Burgasser et al. (2006) See also Gizis et al. (2003); Cruz et al. (2004); Liu et al. (2006); Burgasser (2007,2008)

17 Ultracool Dwarfs: The L/T Transition J H K 1800 K 1400 K Gas opacity Cloud opacity clouds 900 K Ackerman & Marley (2001) See also Cooper et al. (2003); Burrows et al. (2006)

18 Ultracool Dwarfs: The L/T Transition clouds Burgasser et al. (2002) See also Ackerman & Marley (2001)

19 Ultracool Dwarfs: The L/T Transition clouds Stephens et al. (2009) See also Knapp et al. (2004); Cushing et al. (2008)

20 Ultracool Dwarfs: What about the grains? clouds Helling et al. (2006) See also Lunine et al. (1989); Ackerman & Marley (2001); Cooper et al. (2003); Helling & Woitke (2006); Helling et al. (2008)

21 Ultracool Dwarfs: Progress in Modeling? clouds Helling et al. (2008) See also Burgasser et al. (2008); Cushing et al. (2008); Stephens et al. (2009)

22 Ultracool Dwarfs: How do we find the best model? clouds Cushing et al. (2008) See also Burgasser et al. (2008ab); Stephens et al. (2009)

23 Ultracool Dwarfs: Summary Abundant evidence for dust grain & cloud formation in L dwarfs Clear evidence for vertical upwelling in T dwarfs (solved problem?) Evolution of clouds at L dwarf/t dwarf transition not understood in detail; dynamics probably critical Grain properties are a growth sector opacities may not be well understood Cloudy L dwarf spectra still not adequately reproduced full 3D modeling is probably required

24 + Clouds & dynamics in exoplanet atmospheres

25 Hot Exoplanets: Atmospheric dynamics HD b Atmospheric dynamics Clouds Atmospheric structure Variability Knutson et al. (2007,2009) see also Harrington et al. (2006); Cowan et al. (2007)

26 Hot Exoplanets: Atmospheric dynamics 30 mbar Atmospheric dynamics Clouds Atmospheric structure Variability 1 bar Showman et al. (2009) see also Cho et al. (2003,2008); Cooper & Showman (2005,2006); Langton & Laughlin (2007,2008); Dobbs-Dixon & Lin (2008); Menou & Rauscher (2009)

27 Hot Exoplanets: Low albedos suggest few clouds Atmospheric dynamics Clouds Atmospheric structure Variability HD b A B < 0.08 Jupiter A B = 0.5 Rowe et al. (2008)

28 Hot Exoplanets: Stratospheres and exospheres Temperature Inversion Atmospheric dynamics Clouds Atmospheric structure Variability Burrows et al. (2008) see also Knutson et al. (2008); Fortney et al. (2006,2008); Seager et al. (2008)

29 Hot Exoplanets: variability Atmospheric dynamics Clouds Atmospheric structure Variability Laughlin et al. (2009)

30 Hot Exoplanets: Summary Dynamics are necessary to explain latitudinal heat variations, largely encaptured in shallow water & GCM modeling. Properties/presence of /clouds less understood Additional atmospheric structure due to irradiative forcing Temporal variability remains to be established

31 + An opportunity for synergy Brown Dwarf Studies Exoplanet GCMs brown dwarfs Observational constraints on brown dwarf cloud properties exoplanet clouds/albedos Opacities of tracer species (FeH, CH 4, amorphous silicates &c.) A robust quantitative method for model/data comparisons (Madhusudhan & Seager 2009)

32 + Thank you!