Download 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
Alycia J. Weinberger - Carnegie DTM
Nearby Star Forming Regions


Good News: Most are in the South
Bad News: All are >100 pc away
 Ophiuchus
-24
 Lupus
-38
 Corona Aust -37
 Chamaeleon -77
 Upper Sco
-30
120 pc
100 pc
170 pc
170 pc
140 pc
≤1 Myr
≤ 1 Myr
≤ 1 Myr
2.5 Myr
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
Weinberger - 10/4/2010
Planetary Formation Timescales
Starformation
to solid
formation
Massive,
gas-rich
disk
Planetesimal
dominated
disk
Gas Removal
Dust / planet
dominated disk
Giant planets
form
Astronomer’s
t0
106 yrs
CAI /
Chondrule
Formation
Weinberger - 10/4/2010
Alycia Weinberger 2009
Terrestrial
planets
form
107 yrs
108 yrs
Moon
forming
Impact (30+ Myr)
109 yrs
Late Heavy
Current age of
Bombardment
the Sun:
(600 Myr)
4.5x109 yrs.
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.
Weinberger - 10/4/2010
Disks: How to make, compose and
possibly destroy planets
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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.
335 yr
Need high contrast in
near-infrared: 10-7 to
10-9
339 yr
Synergy with ALMA
346 yr
Weinberger - 10/4/2010
(Jang-Condell & Boss 2007)
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
Weinberger - 10/4/2010
Salyk et al. 2008, ApJL
NIRSPEC, R~25,000
Imaging Ices
Imaging of scattering from water ice in disks
HD 142527
mJy/sq.arcsec
(Honda et al. 2009)
(Inoue et al. 2008)
Weinberger - 10/4/2010
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
S/N=280


Need excellent calibration in
high continuum/line sources
Weinberger - 10/4/2010
-30
QuickTime™ and a
decompressor
are needed to see this picture.
-20
-10
0
10
Velocity [km/s]
20
30
Pontoppidan et al. 2008, ApJ, 684, 1323
VLT CRIRES+AO, Tint=32 min, R~100K
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)
Weinberger - 10/4/2010
HD 141569A
Disk is transitional
•Contains gas
Effect of
Companions?
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)
Weinberger - 10/4/2010
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
QuickTime™ and a
decompressor
are needed to see this picture.
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)

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Goto et al. 2006, ApJ, 652, 758
Subaru IRCS+AO, Tint=20 min, R~20K
Terrestrial O3
Spatially Resolved Spectra of Emission
•
•
•
Central Disk Spectrum
24 AU (0.’’24)
(Rainbow step every 24 AU)
168 AU (1.’’68)
192 AU (1.92 AU) - Backgd
~1.5 hr at Keck
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Weinberger et al. in prep
Young Planets Themselves: Where
they are and what they are made of
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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
Weinberger - 10/4/2010
IMACS 12x12’
(Gully-Santiago)
Analogs and Intrinsically Interesting
1 MJ object = 840 K, i.e. T dwarf, with K~19
~1 hr at R~400 with GMT
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(Knapp et al. 2004)
Discovery Space for Planet Imaging
QuickTime™ and a
decompressor
are needed to see this picture.
Weinberger - 10/4/2010
Olivier Guyon (U. AZ)
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)
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.
Weinberger - 10/4/2010
McElwain et al. 2008
Keck, OSIRIS
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)
Weinberger - 10/4/2010
Quanz et al. 2010
Spectra of Young Exosolar Planets
Fomalhaut planet
appears
dominated by a
scattered light
disk. Could learn
about both.
Tiger
(Kalas et al. 2008)
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Detecting Planets in Debris Disks
Figure Credit: Chris Stark (U MD)
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.
Weinberger - 10/4/2010
Stellar and Disk Co-Evolution
(Tom Greene)
Weinberger - 10/4/2010
Embedded protostar with disk
Class II
Log (Flux Density)
Log (Flux Density)
Flat spectrum and/or “Class I”
1
100
Log() [m]
1
100
Log() [m]
Want to learn simultaneously about the star and its disk
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.
Weinberger - 10/4/2010
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
Weinberger - 10/4/2010
log g
Astrophysics of Young Stars
Log (Teff)
(Doppmann et al. 2005)
Keck 0.3-2 hr /source a R~18,000
Origin of Isotope Ratios
(R. Smith et al. 2009)


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
Weinberger - 10/4/2010
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
Weinberger - 10/4/2010