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Catching Planets in Formation with GMT

Catching Planets in Formation with GMT. What sets the stellar/substellar mass function and how universal is it? Do all stars form planets and if not, why not? What causes the diversity of planetary systems?. SPECIMEN. Nearby Star Forming Regions. Good News: Most are in the South

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Catching Planets in Formation with GMT

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  1. Catching Planets in Formation with GMT What sets the stellar/substellar mass function and how universal is it? Do all stars form planets and if not, why not? What causes the diversity of planetary systems? SPECIMEN Alycia J. Weinberger - Carnegie DTM

  2. Nearby Star Forming Regions • Good News: Most are in the South • Bad News: All are >100 pc away • Ophiuchus -24 120 pc ≤1 Myr • Lupus -38 100 pc ≤ 1 Myr • Corona Aust -37 170 pc ≤ 1 Myr • Chamaeleon -77 170 pc 2.5 Myr • Upper Sco -30 140 pc 5 Myr 4 AU at 150 pc = 27 mas (separate “inner” and “outer” Solar System) Diffraction limit (/D) of GMT at 1.6 m is 13 mas

  3. Planetary Formation Timescales Star-formation to solid formation Massive, gas-rich disk Planetesimal dominated disk Dust / planet dominated disk Gas Removal Giant planets form Terrestrial planets form Astronomer’s t0 106 yrs 107 yrs 108 yrs 109 yrs CAI / Chondrule Formation Moon forming Impact (30+ Myr) Late Heavy Bombardment (600 Myr) Current age of the Sun: 4.5x109 yrs. Alycia Weinberger 2009

  4. Main Questions • Substantial mismatch between predicted and observed distribution of exoplanets. • Major uncertainties: • How do gas-giant planets form. • How much do planets migrate. • Are there many habitable (water, etc) planets. • Need to extend observational phase space: • Probe lower masses. • Detect very young planets. • Determine composition.

  5. Disks: How to make, compose and possibly destroy planets

  6. Watching planet formation 10 mas 30 mas If planets form by gravitational instability (Boss 1997), spiral arms in disk may be observable in scattered light. Need high contrast in near-infrared: 10-7 to 10-9 Synergy with ALMA 335 yr 339 yr 346 yr (Jang-Condell & Boss 2007)

  7. Where is ice line / where is the water? • Giant planets may form more efficiently outside the ice-line • Water-rich planetesimals from outside the ice-line may deliver water to dry inner planets Salyk et al. 2008, ApJL NIRSPEC, R~25,000

  8. Imaging Ices Imaging of scattering from water ice in disks HD 142527 mJy/sq.arcsec (Honda et al. 2009) (Inoue et al. 2008)

  9. What are gas densities in planet region? • “Spectroastrometry” • Analogous to centroiding to 0.01 pixel • Find gas within 1/100 of a spatial resolution element (~0.3 mas for VLT, 0.1 mas for GMT) • Requires S/N>100 on continuum and resolving line kinematically • Need aperture for low line flux sources: detections are 10-16 - 10-17 W/m2 • Need excellent calibration in high continuum/line sources S/N=280 -30 -20 -10 0 10 20 30 Velocity [km/s] Pontoppidan et al. 2008, ApJ, 684, 1323 VLT CRIRES+AO, Tint=32 min, R~100K

  10. Observing planets in disks It should be possible to detect planets forming in the outer parts of classical T Tauri star disks (Jang-Condell & Kuchner 2010)

  11. Effect of Companions? HD 141569A • Disk is transitional • Contains gas • Scattered Light • Large extent (400 AU) • Red visible – near-IR color • Mid-IR Emission • Compact extent • PAHs Star: A0, 16.5 L, 5 Myr old (Weinberger et al. in prep)

  12. Spatially resolved disk kinematics When do planets form? When does gas in inner disk disappear? • AO allows disk rotation curves • Combined constraint of kinematics and size • Consider the relevant scales • GMT DL at 5 m = 0.04 • Closest sites of ongoing star formation - 150 pc; GMT probes 6 AU (about where Jupiter formed) Goto et al. 2006, ApJ, 652, 758 Subaru IRCS+AO, Tint=20 min, R~20K

  13. Spatially Resolved Spectra of Emission Central Disk Spectrum 24 AU (0.’’24) Terrestrial O3 (Rainbow step every 24 AU) 168 AU (1.’’68) 192 AU (1.92 AU) - Backgd ~1.5 hr at Keck Weinberger et al. in prep

  14. Young Planets Themselves: Where they are and what they are made of

  15. Free Floaters • How many stars/brown dwarfs are there? • Do they have disks? • Is the disk lifetime the same as for stars? Example: Ophiuchus Size: ~7 X 7 Deg (cloud core plus extended region) GMACS FOV: 8 x 18’ NIRMOS FOV:5.5 x 5.5’ IMACS limiting magnitude I~21.5, S/N=30, in 4 hr @ R~2000 10-4 Lsun or 3- 5MJ 15% too faint (>21.5) for IMACS (Gully-Santiago) IMACS 12x12’

  16. Analogs and Intrinsically Interesting 1 MJ object = 840 K, i.e. T dwarf, with K~19 ~1 hr at R~400 with GMT (Knapp et al. 2004)

  17. Discovery Space for Planet Imaging Olivier Guyon (U. AZ)

  18. Discovery Space for Young Planets • Contrast of young giant planet and star ~10-6 makes them easier to image • “TIGER” instrument is being developed as potential first-light imager. (Phil Hinz, U. AZ)

  19. Planet Spectroscopy GMTIFS offset to “planet” location. Use spatial information to correct for scattered light at each wavelength. Preferable to long slit. McElwain et al. 2008 Keck, OSIRIS

  20. Example:  Pic Planet (~8 MJup) • 0.’’35 from and 7.7 mag fainter than the star • “only” need 104 contrast • This is >10 /D for GMT • L’/M=11.1 mag (in principle can get GMTNIRS spectrum at S/N=100 in 1 hr) • Molecular composition • Auroral emission (magnetic field) • Variability (rotation, winds) Quanz et al. 2010

  21. Tiger Spectra of Young Exosolar Planets Fomalhaut planet appears dominated by a scattered light disk. Could learn about both. (Kalas et al. 2008)

  22. Detecting Planets in Debris Disks Figure Credit: Chris Stark (U MD)

  23. Uses of 1st Generation Instruments for star and planet formation studies • GMTNIRS - Probing stellar astrophysics, disk kinematics and disk and even planet composition, radial velocity studies • Tiger - Imaging disks and planets in disks, composition • GMTIFS - Imaging young planets, disks • GMTNIRS / GMACS - Studying free floating planets and brown dwarfs in star forming regions • GCLEF - Debris disk gas, radial velocity studies GMT will enable many creative projects not envisioned yet and like each generation of large telescope, enable qualitative leaps in measurement ability.

  24. Stellar and Disk Co-Evolution (Tom Greene)

  25. Embedded protostar with disk Class II Flat spectrum and/or “Class I” Log (Flux Density) Log (Flux Density) 1 100 Log() [m] 1 100 Log() [m] Want to learn simultaneously about the star and its disk

  26. Stellar Magnetic Fields Disk evolution is supposedly magnetically driven Only a handful of stars have directly measured fields (Johns-Krull et al. 2009) Measure Zeeman splitting (or broadening) of lines such as Ti I.

  27. Astrophysics of Young Stars A wide range of luminosities and gravities (and therefore ages) appear for stars of all types Most embedded, veiled objects do seem younger than optically revealed ones (White & Hillenbrand 2004)-- need IR log g Log (Teff) (Doppmann et al. 2005) Keck 0.3-2 hr /source a R~18,000

  28. CO self-shielding: Lyons & Young (2005) suggested that irradiation of our young disk generated our 18O/17O/16O ratios Need O to be incorporated into water Origin of Isotope Ratios (R. Smith et al. 2009)

  29. Direct Observations of Circumstellar Disks and origins of the diversity of planetary systems • Disk Spectroscopy • Direct measurement of gas content and temperature • High spectral resolution proxy for spatial resolution (gas close to the star moves fast) • High spatial resolution to resolve the disk directly (Spectroastrometry) • Disk Imaging • Direct measurement of structure • Composition from low-resolution spectroscopy of emitted and scattered light

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