1. Planets around Low-Mass Stars and Brown Dwarfs Michael Liu Bruce Macintosh NGAO Workshop, Sept 2006

2. 2 Planets around VLM stars & brown dwarfs Direct imaging and spectroscopy of planets easier around low-mass stars and brown dwarfs.Direct imaging and spectroscopy of planets easier around low-mass stars and brown dwarfs. Study objects with SEDs & atmospheres similar to “regular” exoplanets, but perhaps with diff origin.Study objects with SEDs & atmospheres similar to “regular” exoplanets, but perhaps with diff origin. High contrast LGS + IR tiptilt needed.High contrast LGS + IR tiptilt needed. ~5 M Jup ? ~25 M Jup Chauvin et al (2005): VLT AO (IR WFS)

3. 3 NGAO: Planet detection sensitivity Very high contrast in near-IR enables imaging of Jovian- mass planets around low-mass stars and brown dwarfs.Very high contrast in near-IR enables imaging of Jovian- mass planets around low-mass stars and brown dwarfs. This can only be done by NGAO. The stars are too optically faint for ExAO systems (I<8-9).This can only be done by NGAO. The stars are too optically faint for ExAO systems (I<8-9). A unique avenue for testing planet formation models, by using a wide range of stellar host mass.A unique avenue for testing planet formation models, by using a wide range of stellar host mass.

4. 4 NGAO opens a unique realm for high contrast studies for a broad range of science programs. AO system Contrast Extreme AO v. bright stars only 10 7 –10 8 Keck NGAO many targets 10 5 –10 6

5. 5 Modeling the targets for NGAO Census of solar neighborhood is very incomplete now …Census of solar neighborhood is very incomplete now … But in ~5 years will be much better (Pan-STARRS)But in ~5 years will be much better (Pan-STARRS) Can build a budget of planet return as a function of contrast and IR T/T sensitivityCan build a budget of planet return as a function of contrast and IR T/T sensitivity ( preliminary )

6. 6 Key actions Detail science case including observing scenarios –E.g. polarimetry, PSF subtraction, etc Prepare a maintainable contrast error budget –Should this be 1d or 2d? Analytic? Simulations? How to keep current? Who owns it? Identify a strawman coronagraph architecture –Is this part of AO, science instrument, or in-between? Carry out analytic simulations of some key cases Figure out who actually does this –Who does the work? Who pays for it? Who leads the area?

7. 7 Sample analytic error budget

8. 8 Sample simulation: effect of static calibration error on contrast

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10. 10 Why do we need NGAO? Very high-contrast near-IR imaging directly image planets and debris disksVery high-contrast near-IR imaging directly image planets and debris disks Large sky coverage study stars over a very wide range of masses & agesLarge sky coverage study stars over a very wide range of masses & ages Multi-band optical and IR wavelengths determine properties & evolution of circumstellar materialMulti-band optical and IR wavelengths determine properties & evolution of circumstellar material

11. 11 Debris Disks: Extrasolar analogs to the asteroid & Kuiper Belt structurestructure compositioncomposition evolutionevolution low-mass planetslow-mass planets Keck NGS: H-band Resolved disks are a goldmine for studying: 100’s of these known from integrated light, but only ~12 resolved to date (2 by AO).

12. 12 Debris disks studies with NGAO simulated 3-hour H-band integration of massive Kuiper Belt in the Pleiades (120 Myr, 130 pc) Undetectable Neptune with 1:1 resonant dust ring NGAO could image many (10s-100s) analogs to the young solar system, study other Kuiper Belts & low-mass planets Solar system modelHigh Strehl NGAOKeck AO today

13. 13 The End