1. Methane imaging of Pleiades T Dwarfs
Sarah Casewell

2. T dwarfs in the Pleiades
Why T dwarfs?
Low mass end of star formation models
Atmosphere models L-T transition
Why the Pleiades?
Best understood cluster in the night sky
Valid Lithium age for the cluster
Robust age for evolutionary models
Talk about bds, why we study them and why the Pleiades

3. Survey area
Numbered are WFCAM fields, letters are cfht – 2.5 square degree overlap.

4. I,I-Z CMD candidates Blue: Selected objects Cyan: Known members
Red: DUSTY model
Black: NextGen model
Black is all I-Z objects from CFH12k. Black is nextgen, red, dusty. Blue are selected objects. Pale blue previoiuly identified cluster members used as a guide to the sequence.

5. Z,Z-J CMD candidates Red: PM candidates Cyan: PM members
Blue: DUSTY model
Black: NextGen model
Z, Z-J blue open squares are the Z-J selected objects only. Black objects are selected objects from I, I-Z
Red, objects that have been selected from this diagram. Blue objects are candidate members. Previously identified members used as a guide to the sequence have a circle around them. Black is nextgen, blue dusty

6. H,J-H CMD candidates Red: DUSTY model Black: NextGen model
Blue: Moraux members
Green: Bihain members
Late L
H, J-H nextgen black, red dusty, green bihain, blue estelle, red diamonds new points from z-j data only. Black points new data
Early to mid T

7. J,J-K CMD candidates Red: DUSTY model Black: NextGen model
Blue: Moraux members
Green: Bihain members
K, J-K. Point out what symbols are. Green Bihian, Blue Estelle, Red Bouvier, 4 black points new members – black line NEXTGEN, red is DUSTY. Point out that the onset of methane and clouds sinking causes the blueward sequence.
Early T
Late L

8. Methane Imaging
How does it work?
Describe spectra and methane

9. Negative results PLZJ 112 PLZJ 235 PLZJ721
Future work on the Pleiades project.
Talk about disks around brown dwarfs
PLZJ 112
PLZJ 235
PLZJ721

10. Colours
Show tinney diagrams tinney et al., 2005, AJ, 130, 2326

11. Colours
Show tinney diagrams tinney et al., 2005, AJ, 130, 2326

12. Colours
Show tinney diagrams tinney et al., 2005, AJ, 130, 2326

13. Colours
Isotherms at and 1500 K High gravity is diamond, Box is low and 4.5 log g.

14. Colours
Same as above but with models?

15. Colours
Show same temp and grav model but different types? Burrows/cond ?

16. Colours
Isotherms at and 1500 K High gravity is diamond, Box is low

17. Colours
Isotherms at and 1500 K High gravity is diamond, Box is low

18. Colours
Isotherms at and 1500 K High gravity is diamond, Box is low
Despite the differences in colours – the models do look similar

19. Conclusions Used CFHT and UKIRT to discover 5 T dwarf candidates
Methane images show 3 are not point sources
Used COND and CLR models and filters to generate tracks
COND are good for J-K, CLR for H-K
Pleiades objects are on L-T transition
Summarise what I/we did
P. Dobbie, S. Hodgkin, E. Moraux, R. Jameson,  N. Hambly, J. Irwin, N Lodieu.