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Alycia J. Weinberger - Carnegie DTM Catching Planets in Formation with GMT n What sets the stellar/substellar mass function and how universal is it? n.

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Presentation on theme: "Alycia J. Weinberger - Carnegie DTM Catching Planets in Formation with GMT n What sets the stellar/substellar mass function and how universal is it? n."— Presentation transcript:

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

2 Weinberger - 10/4/2010 Nearby Star Forming Regions n Good News: Most are in the South n 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 pc2.5 Myr  Upper Sco-30  140 pc5 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 Weinberger - 10/4/2010 10 6 yrs10 7 yrs10 8 yrs10 9 yrs CAI / Chondrule Formation Moon forming Impact (30+ Myr) Current age of the Sun: 4.5x10 9 yrs. Late Heavy Bombardment (600 Myr) Star- formation to solid formation Massive, gas-rich disk Planetesimal dominated disk Dust / planet dominated disk Gas Removal Giant planets form Terrestrial planets form Planetary Formation Timescales Astronomer’s t 0 Alycia Weinberger 2009

4 Weinberger - 10/4/2010 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. Main Questions

5 Weinberger - 10/4/2010 Disks: How to make, compose and possibly destroy planets

6 Weinberger - 10/4/2010 Watching planet formation 335 yr 339 yr 346 yr 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 (Jang-Condell & Boss 2007) 10 mas30 mas

7 Weinberger - 10/4/2010 Where is ice line / where is the water? n Giant planets may form more efficiently outside the ice-line n 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 Weinberger - 10/4/2010 Imaging Ices (Inoue et al. 2008) Imaging of scattering from water ice in disks mJy/sq.arcsec (Honda et al. 2009) HD 142527

9 Weinberger - 10/4/2010 What are gas densities in planet region? n “Spectroastrometry” u Analogous to centroiding to 0.01 pixel u Find gas within 1/100 of a spatial resolution element (~0.3 mas for VLT, 0.1 mas for GMT) u Requires S/N>100 on continuum and resolving line kinematically u Need aperture for low line flux sources: detections are 10 -16 - 10 -17 W/m 2 F Need excellent calibration in high continuum/line sources Pontoppidan et al. 2008, ApJ, 684, 1323 VLT CRIRES+AO, T int =32 min, R~100K S/N=280 -30 -20 -10 0 10 20 30 Velocity [km/s]

10 Weinberger - 10/4/2010 Observing planets in disks (Jang-Condell & Kuchner 2010) It should be possible to detect planets forming in the outer parts of classical T Tauri star disks

11 Weinberger - 10/4/2010 Effect of Companions? Disk is transitional Contains gas Scattered Light Large extent (400 AU) Red visible – near-IR color HD 141569A Mid-IR Emission Compact extent PAHs Star: A0, 16.5 L , 5 Myr old (Weinberger et al. in prep)

12 Weinberger - 10/4/2010 Spatially resolved disk kinematics n AO allows disk rotation curves u Combined constraint of kinematics and size n Consider the relevant scales  GMT DL at 5  m = 0.  04 u 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, T int =20 min, R~20K When do planets form? When does gas in inner disk disappear?

13 Weinberger - 10/4/2010 Spatially Resolved Spectra of Emission Terrestrial O 3 Central Disk Spectrum 24 AU (0.’’24) 168 AU (1.’’68) 192 AU (1.92 AU) - Backgd (Rainbow step every 24 AU) Weinberger et al. in prep ~1.5 hr at Keck

14 Weinberger - 10/4/2010 Young Planets Themselves: Where they are and what they are made of

15 Weinberger - 10/4/2010 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- 5M J 15% too faint (>21.5) for IMACS IMACS 12x12’ (Gully-Santiago)

16 Weinberger - 10/4/2010 Analogs and Intrinsically Interesting 1 M J object = 840 K, i.e. T dwarf, with K~19 ~1 hr at R~400 with GMT (Knapp et al. 2004)

17 Weinberger - 10/4/2010 Discovery Space for Planet Imaging Olivier Guyon (U. AZ)

18 Weinberger - 10/4/2010 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 Weinberger - 10/4/2010 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 Weinberger - 10/4/2010 Example:  Pic Planet (~8 M Jup ) 0.’’35 from and 7.7 mag fainter than the star “only” need 10 4 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 Weinberger - 10/4/2010 Spectra of Young Exosolar Planets Tiger Fomalhaut planet appears dominated by a scattered light disk. Could learn about both. (Kalas et al. 2008)

22 Weinberger - 10/4/2010 Detecting Planets in Debris Disks Figure Credit: Chris Stark (U MD)

23 Weinberger - 10/4/2010 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 Weinberger - 10/4/2010 Stellar and Disk Co-Evolution (Tom Greene)

25 Weinberger - 10/4/2010 Embedded protostar with disk 1 100 Log( ) [  m] Log (Flux Density) Flat spectrum and/or “Class I” Log (Flux Density) Class II Want to learn simultaneously about the star and its disk 1 100 Log( ) [  m]

26 Weinberger - 10/4/2010 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 Weinberger - 10/4/2010 Astrophysics of Young Stars Log (Teff) log g (Doppmann et al. 2005) Keck 0.3-2 hr /source a R~18,000 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

28 Weinberger - 10/4/2010 Origin of Isotope Ratios n CO self-shielding: Lyons & Young (2005) suggested that irradiation of our young disk generated our 18 O/ 17 O/ 16 O ratios n Need O to be incorporated into water (R. Smith et al. 2009)

29 Weinberger - 10/4/2010 Direct Observations of Circumstellar Disks and origins of the diversity of planetary systems n Disk Spectroscopy u Direct measurement of gas content and temperature u High spectral resolution proxy for spatial resolution (gas close to the star moves fast) u High spatial resolution to resolve the disk directly (Spectroastrometry) n Disk Imaging u Direct measurement of structure u Composition from low-resolution spectroscopy of emitted and scattered light


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