1. Galactic Science: Star and Planet Formation
Michael Liu
Andrea Ghez, Tom Greene, Lynne Hillenbrand, Jessica Lu, Bruce Macintosh, Stan Metchev, Nevin Weinberg
Keck SSC meeting, June 2006

2. Galactic Science: Key Science Cases
Extrasolar Planets (Liu, Macintosh)
Debris Disks (Metchev, Liu)
Protostars (Hillenbrand, Greene)
Galactic Center (Weinberg, Ghez, Lu)
M. Liu (IfA/Hawaii)

3. AO is critical for star/planet formation
There are/will be numerous wide-field surveys of the sky for finding young stars of various ages: IRAS, Hipparcos, Chandra, Spitzer, JCMT/SCUBA-2, Pan-STARRS, etc.
Follow-up observations of the relevant physical scales are <1 arcsec: angular resolution & high contrast are critical
NGC 1333, IRAC, 26x34 arcmin
NGC 1333: 34’x26’ Spitzer/IRAC
M. Liu (IfA/Hawaii)

4. Why do we need NGAO?
Very high-contrast near-IR imaging directly image planets and debris disks
Large sky coverage study stars over a very wide range of masses & ages
Multi-band optical and IR wavelengths determine properties & evolution of circumstellar material
M. Liu (IfA/Hawaii)

5. Obligatory star & planet formation slide
M. Liu (IfA/Hawaii)

6. Obligatory star & planet formation slide
M. Liu (IfA/Hawaii)

7. Resolving the protostellar environment= +
Disk+Envelope Density
Temperature Dist.
Use observed integrated-light SEDs + high resolution images to study the evolution of the youngest stars.
M. Liu (IfA/Hawaii)

8. NGAO optical imaging of protostars
Simulated I-band (scattered light) image of a protostar with a massive envelope & disk at 1 kpc
Model image
HST ACS/HRC (70 AU resolution)
Keck NGAO (25 AU resolution)
NGAO provides highest angular resolution of any filled-aperture telescope (and complementary to ALMA for this science).
M. Liu (IfA/Hawaii)

9. Obligatory star & planet formation slide
M. Liu (IfA/Hawaii)

10. Debris Disks: Extrasolar analogs to the asteroid & Kuiper Belt
Keck NGS: H-band
Resolved disks are a goldmine for studying:
structure
composition
evolution
low-mass planets
100’s of these known from integrated light, but only ~12 resolved to date (2 by AO).
M. Liu (IfA/Hawaii)

11. Undetectable Neptune with 1:1 resonant dust ring
Debris disks studies with NGAO simulated 3-hour H-band integration of massive Kuiper Belt in the Pleiades (120 Myr, 130 pc)
Solar system model
High Strehl NGAO
Keck AO today
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
M. Liu (IfA/Hawaii)

12. Obligatory star & planet formation slide
M. Liu (IfA/Hawaii)

13. Planets around VLM stars & brown dwarfs
~5 MJup?
~25 MJup
Chauvin et al (2005): VLT AO (IR WFS)
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.
High contrast LGS + IR tiptilt needed.
M. Liu (IfA/Hawaii)

14. NGAO: Planet detection sensitivity
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).
A unique avenue for testing planet formation models, by using a wide range of stellar host mass.
M. Liu (IfA/Hawaii)

15. 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
107–108
Keck NGAO many targets
105–106
M. Liu (IfA/Hawaii)

16. Why do we need NGAO?
Very high-contrast near-IR imaging directly image planets and debris disks
Large sky coverage study stars over a very wide range of masses & ages
Multi-band optical and IR wavelengths determine properties & evolution of circumstellar material
M. Liu (IfA/Hawaii)

17. The End
M. Liu (IfA/Hawaii)