Post on 05-Jan-2016
Glenn Schneider Glenn Schneider Steward Observatory, University of Arizona (NICMOS/IDT)Steward Observatory, University of Arizona (NICMOS/IDT)
High Contrast ImagingHigh Contrast Imagingand and
The Disk/Planet ConnectionThe Disk/Planet Connection
Asymmetries (radial & azimuthal):• May implicate low-mass perturbers (planets) from: Rings, Central Holes, Gaps, Clumps, Arcs, Arclets• Help Elucidate the scattering & physical properties of the grains.
Observing scattered light from circumstellar debris has been observationally challenging because of the very high Star:Disk contrast ratios in such systems.
1984 - B.A. Smith & R.J. Terrile 6" radius coronagraphic mask, Las Campanas (discovery image)
Until very recently the large, and nearly edge-on disk around Pictoris remained the only such disk imaged. Pictoris
Resolved imaging spatial distribution of dust/debris.
Direct (Scattered Light) Imaging of Dusty DebrisDirect (Scattered Light) Imaging of Dusty Debris
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The HUBBLE Legacy The HUBBLE Legacy Breaking the Low Contrast ParadigmBreaking the Low Contrast Paradigm
• Diffraction Limited Imaging in Optical/Near-IR•> 98% Strehl Ratios @ alls• Highly STABLE PSF• Coronagraphy: NICMOS STIS, ACS
NIR High Dynamic Range Sampling NICMOS/MA: mag=19.4 (6 x 4m)
Background RejectionBackground Rejection1.61.6m: ~10m: ~10-6-6 pix pix-1 -1 @ 1”@ 1”
1.11.1m: ~10m: ~10-5 -5 in 2”-3” annulus in 2”-3” annulus
• Intra-Orbit Field Rotation
TODAY HST Provides a Unique Venue for High Contrast ImagingTODAY HST Provides a Unique Venue for High Contrast Imaging
HST is a stepping HST is a stepping stone for super-stone for super-high contrasthigh contrast
** imagingimaging
**Background Background RejectionRejection10109—9—10101010
Terrestrialplanets
form
Clearing ofinner solar
system,formation of a
Kuipercometary
belt?
108
yrs109
yrs
Era of heavybombarment
by comets
Currentage of
the Sun:5x109 yrs.
PerseiSun
HyadesTucanaeAssoc Pleiades
Primary Dust (≤ m) Secondary Dust (≥Locked to Gas Collisional erosion
Clearing Timescales: P-R drag few 10 Rad. Pressure: ~ 10 From: R. Webb
Collapsingprotostar
forms proto-planetary disk
106
yrs
Taurus,Ophiuchus
star formingregions
m)
64
Rocky coresof giant
planets form
accretegaseous
atmospheres
TW Hydrae
ry s107
Assoc
Giant planets
Planet-Building TimelinePlanet-Building TimelineHST Vis/NIR HST Vis/NIR
High ContrastBeyond HST Vis/UV Super-High Contrast
Young Extra-Solar Planet* &Brown Dwarf Companions
* < few x 106 yr at 1”
2.5"
1"
Circumstellar Disksfdisk/f*
> few x 10-3 at 1”
> 50 mas
Scientific Areas of Investigation EnabledScientific Areas of Investigation EnabledWith Today’s Capabilities on HSTWith Today’s Capabilities on HSTvia PSF-Subtracted Coronagraphic Imagingvia PSF-Subtracted Coronagraphic Imaging
Moving Beyond HST into the Super-High Contrast RegimeMoving Beyond HST into the Super-High Contrast Regime
Exosolar Planet Imaging & Spectroscopy: few x 106 Myr at 1” > 109 yr (solar age) at 1”
Disk Imaging & Spectroscopy: fdisk/f*
> few x 10-3 at 1” ≤ 10-6 at 1” > 50 mas a few mas (sub-AU at 200pc)
OPTICAL CONFIGURATIONS
•Coronagraphy•Polarimetric Nulling•Nulling Interferometry•Wavefront Correction•Station-Keeping Occulters•Interferometric Arrays
TECHNOLOGICAL CHALLENGES
•Micro-Roughness of Optical Surfaces•Particulate/Contamination Control•Stray Light Management & Control•Pupil Apodization (and Shaping)•Metrological Tolerancing & Stability•Wavefront/Mirror Sensing & Control
The Dusty Disk/Planet ConnectionThe Dusty Disk/Planet Connection Current theories of disk/planet evolution suggest a presumed epoch of planet-building via the formation and agglomerative growth of embryonic bodies, and the subsequent accretion of gaseous atmospheres onto hot giant planets, is attendant with a significant decline in the gas-to-dust ratios in the remnant protostellar environments.
In this critical phase of newly formed (or forming) extra-solar planetary systems, posited from a few few megayears to a few tens of megayearsmegayears to a few tens of megayears, the circumstellar environments become dominated by a second-generation population of dust containing larger grains arising from the collisional erosion of planetesimals.
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< 1Myr< 1MyrProplydsProplydsin Orionin Orion
and…and…SubstellarSubstellarObjets toObjets to~ 10 M~ 10 Mjupjup
HH30 Obscured GM AUR UnembeddedHH30 Obscured GM AUR Unembedded
Direct ImageDirect Image
Coronagraph +Coronagraph +PSF SubtractionPSF Subtraction
~ 1— few Myr~ 1— few Myr
. .
Radius (Arcsec) from Hole Center
5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
0.3 0.45 0.6 0.75 0.9 1.05 1.2 1.35 1.5 1.65 1.8 1.95 2.1 2.25 2.4 2.55 2.7 2.85
Azimuthal Averages, 1-Pixel Wide Annular Zones(69:69, 208:209) and (77, 205) Glint Features Excluded
Radius (Pixels) from Hole Center
0 0.075 0.15 0.225 0.3 0.375 0.45 0.525 0.6 0.675 0.75 0.825 0.9 0.975 1.0510-6
10
10-4
10-3
10-2
10-1
100 REDUCTION IN BACKGROUND FLUX FROM F160W PSF
Unocculted F160W PSFPSF + CoronagraphPSF + Coronagraph + Roll
ARCSECONDS
CoronagraphicHole
Radius = 0.3"
1pixel
-5
Coronagraph +Coronagraph +
PSF SubtractionPSF Subtraction
Collapsingprotostar
forms proto-planetary disk
106
yrs
Taurus,Ophiuchus
star formingregions
Planet-Building TimelinePlanet-Building Timeline
HH 30
Collapsingprotostar
forms proto-planetary disk
106
yrs
Taurus,Ophiuchus
star formingregions
Planet-Building TimelinePlanet-Building Timeline
QuickTime™ and aSorenson Video decompressorare needed to see this picture.
Rocky coresof giant
planets form
Collapsingprotostar
forms proto-planetary disk
106
yrs
Taurus,Ophiuchus
star formingregions
Planet-Building TimelinePlanet-Building Timeline
accretegaseous
atmospheres
TW Hydrae
ry s107
Assoc
Giant planets
141569A
Terrestrialplanets
form
Clearing ofinner solar
system,formation of a
Kuipercometary
belt?
108
yrs109
yrs
Era of heavybombarment
by comets
Currentage of
the Sun:5x109 yrs.
PerseiSun
HyadesTucanaeAssoc Pleiades
Primary Dust (≤ m) Secondary Dust (≥Locked to Gas Collisional erosion
Clearing Timescales: P-R drag few 10 Rad. Pressure: ~ 10
From: R. Webb
Collapsingprotostar
forms proto-planetary disk
106
yrs
Taurus,Ophiuchus
star formingregions
m)
64
Rocky coresof giant
planets form
accretegaseous
atmospheres
TW Hydrae
ry s107
Assoc
Giant planets
Planet-Building TimelinePlanet-Building Timeline
Examples of Dusty Disks with Radial and Hemispheric Brightness Examples of Dusty Disks with Radial and Hemispheric Brightness Anisotropies and Complex Morphologies, Possibly Indicative of Anisotropies and Complex Morphologies, Possibly Indicative of Dynamical Interactions with Unseen Planetary Mass Companions, Dynamical Interactions with Unseen Planetary Mass Companions, Spatially Resolved and Imaged Around Young (< 10 Myr) Stars by HST.Spatially Resolved and Imaged Around Young (< 10 Myr) Stars by HST.
N
E
1 "
HR 4796A (A0V), ~ 8 MyrA 70AU radius ring, ~ 12 AU wide ring of very red material, exhibiting strong forward scattering and ansally asymmetric hemispheric flux densities.
A 400AU radius disk, with a broad, partially filled asymmetric gap containing a “spiral” arclet.
HD 141569A(Herbig Ae/Be)~ 5 Myr
Examples of Dusty Disks with Radial and Hemispheric Brightness Examples of Dusty Disks with Radial and Hemispheric Brightness Anisotropies and Complex Morphologies, Possibly Indicative of Anisotropies and Complex Morphologies, Possibly Indicative of Dynamical Interactions with Unseen Planetary Mass Companions, Dynamical Interactions with Unseen Planetary Mass Companions, Spatially Resolved and Imaged Around Young (< 10 Myr) Stars by HST.Spatially Resolved and Imaged Around Young (< 10 Myr) Stars by HST.
TW Hya (K7) “Old” PMS Star
Pole-on circularly symmetric disk with a break in its surface brightness profile at 120 AU (2”).
Examples of Dusty Disks with Radial and Hemispheric Brightness Examples of Dusty Disks with Radial and Hemispheric Brightness Anisotropies and Complex Morphologies, Possibly Indicative of Anisotropies and Complex Morphologies, Possibly Indicative of Dynamical Interactions with Unseen Planetary Mass Companions, Dynamical Interactions with Unseen Planetary Mass Companions, Spatially Resolved and Imaged Around Young (< 10 Myr) Stars by HST.Spatially Resolved and Imaged Around Young (< 10 Myr) Stars by HST.
TW Hya (K7) “Old” PMS Star
Pole-on circularly symmetric disk with a break in its surface brightness profile at 120 AU (2”).
and, possibly, a radially and azimuthally confined arc-like depression.
Examples of Dusty Disks with Radial and Hemispheric Brightness Examples of Dusty Disks with Radial and Hemispheric Brightness Anisotropies and Complex Morphologies, Possibly Indicative of Anisotropies and Complex Morphologies, Possibly Indicative of Dynamical Interactions with Unseen Planetary Mass Companions, Dynamical Interactions with Unseen Planetary Mass Companions, Spatially Resolved and Imaged Around Young (< 10 Myr) Stars by HST.Spatially Resolved and Imaged Around Young (< 10 Myr) Stars by HST.
HR 4796AHR 4796A
1.1m 0.58m
Ansal Separation (Peaks) = 2.107” ± 0.0045”
Major Axis of BFE = 2.114” ± 0.0055"
P.A. of Major Axis (E of N) = 27.06° ± 0.18°
Major:Minor Axial Length = (3.9658 ± 0.034): 1
Inclination of Pole to LOS = 75.73° ± 0.12°
Photocentric Offset from BFE(Y) = -0.0159" ± 0.0048"
Photocentric Offset from BFE(X) = +0.0031" ± 0.0028"
HR 4796A RING GEOMETRYHR 4796A RING GEOMETRY(Least-Squares Isophotal Ellipse Fit)
00.10.20.30.40.50.60.70.80.91
1.1
-1.6 -1.5 -1.4 -1.3 -1.2 -1.1 -1 -0.9 -0.8 -0.7 -0.6
NE ANSA CROSS-SECTIONAL PROFILE
Distance (Arc Seconds)
0.197"
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
-1.6 -1.5 -1.4 -1.3 -1.2 -1.1 -1 -0.9 -0.8 -0.7 -0.6
NE ANSA CROSS-SECTIONAL PROFILE
Distance (Arc Seconds)
0.197"
Bri
ghtn
ess
(Nor
mal
ized
to N
E A
nsa)
HR 4796A Circumstellar Debris Ring - WIDTHHR 4796A Circumstellar Debris Ring - WIDTH
FWHM ring = 0.184”
FWHM: 12.3±0.7AU 8.7% Dring
1-e-1 = 0.265”
PSF point source = 0.070”Measured = 0.197”
WIDTH AT NE ANSA
1-e-1: 17.7±10.1AU 12.5% Dring
*
20% inner:outerfall-off asymmetry
*
Ansal Separation (Peaks) = 2.107” ± 0.0045”
Major Axis of BFE = 2.114” ± 0.0055"
P.A. of Major Axis (E of N) = 27.06° ± 0.18°
Major:Minor Axial Length = (3.9658 ± 0.034): 1
Inclination of Pole to LOS = 75.73° ± 0.12°
Photocentric Offset from BFE(Y) = -0.0159" ± 0.0048"
Photocentric Offset from BFE(X) = +0.0031" ± 0.0028"
RING GEOMETRY - Least-Squares Isophotal Ellipse FitRING GEOMETRY - Least-Squares Isophotal Ellipse Fit
““FACE-ON” PROJECTION - With Flux ConservationFACE-ON” PROJECTION - With Flux Conservation
Spatially Resolved Relative PHOTOMETRY of the RingSpatially Resolved Relative PHOTOMETRY of the Ring
N-S
igm
a
Bri
ghtn
ess
Rat
io (
Per
cent
)
NW:SE Surface Brightness AnisotropyNW:SE Surface Brightness Anisotropy
30
40
50
60
70
80
90
NE % Peak CountsSW % Peak Counts% SW/NE
Angle from Major Axis (Degrees)
-2
0
2
4
6
8
-60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60
(%SW - %NE) : SIGMA (%SW/%NE)
100 BACK FRONT
N-S
igm
a
Bri
ghtn
ess
Rat
io (
Per
cent
)
0123456
0 10 20 30 40 50 60
(NE Front-Back) : SIGMA(Front/Back)(SW Front-Back) : SIGMA(Front/Back)(MEAN Front-Back) : SIGMA(Front/Back)
100
110
120
130
140
150
160
170 NE % FRONT:BACKSW % FRONT:BACKMEAN FRONT:BACK1 + 0.73*COS(theta)
Angle from Major Axis (Degrees)
Front:Back Surface Brightness AnisotropyFront:Back Surface Brightness Anisotropy
Broad Colors of the HR 4796A Debris RingBroad Colors of the HR 4796A Debris Ring[50CCD]-[F110W]=0.55±0.09[50CCD]-[F160W]=1.14+0.20
-0.17
Intrinsically red grains
•Consistent with collisionally evolved population of particle sizes > few microns
•Not primordial ISM grains
•Similar intrinsic colors to TNOsin our solar system [V]-[J]=+1.07*
•Consistent with laboratory* irradiation experiments on a varietyof organics to study reddening ofD & P type asteroids with distance From Sun.
*Barucci et al (1993); Andronico et al (1987)
Terrestrialplanets
form
Clearing ofinner solar
system,formation of a
Kuipercometary
belt?
108
yrs109
yrs
Era of heavybombarment
by comets
Currentage of
the Sun:5x109 yrs.
PerseiSun
HyadesTucanaeAssoc Pleiades
Primary Dust (≤ m) Secondary Dust (≥Locked to Gas Collisional erosion
Clearing Timescales: P-R drag few 10 Rad. Pressure: ~ 10
From: R. Webb
Collapsingprotostar
forms proto-planetary disk
106
yrs
Taurus,Ophiuchus
star formingregions
m)
64
Rocky coresof giant
planets form
accretegaseous
atmospheres
TW Hydrae
ry s107
Assoc
Giant planets
Planet-Building TimelinePlanet-Building Timeline
0
6 7 8 9 10Log10 Age (years)
80Mjup
14Mjup
JUPITER
SATURN
STARS (Hydrogen burning)
BROWN DWARFS (Deuterium burning)
PLANETS
200Mjup
Evolution of M Dwarf Stars, Brown Dwarfsand Giant Planets (from Adam Burrows)
-10
-8
-6
-4
-2
Log
10 L
/Lsu
m
sun
Cooling Curves for Substellar ObjectsCooling Curves for Substellar Objects
CORONAGRAPHICCORONAGRAPHICCOMPANIONCOMPANIONDETECTIONDETECTION
(Multiaccum) Imagingat two S/C orientations(in a single HST visability period).
Background objectsrotate about occultedTarget. PSF structuresand optical artifactsdo not.
TWA6. Two Integrations: Median of 3 Multiaccum Each
Roll = 30° Time = 20 minutes
Above: Coronagraphic Images
Roll: 30°
Above: Coronagraphic Images
Roll: 30°
Left: Difference Image
Same display dynamic range
H “companion” = 20.1H = 13.2, =2.5”
At =2.5” background brightness is reduced by an ADDITIONAL factor of 50 over raw coronagraphic gain (ofappx 4).
Each independent image of TWA6“B” is S/N ~20 in difference frame.
Imperfections inPSF-subtractionsresult in residualsexpected from purephoton noise.
Systematics:
OTA “Breathing”
Target Re-centration
Coron. Edge Effects
Mechanical Stability
Detectability and Spatial CompletenessDetectability and Spatial Completeness
(() Dependence via Model PSF Implantation) Dependence via Model PSF Implantation
Observed Model* Nulled Implant
*TinyTim 5.0 HST+NICMOS Optical Model - Krist
Detectability: (Detectability: () Dependence via Model PSF Implantation) Dependence via Model PSF Implantation
.
4
8
12
16
20
25%
Rec
over
ed F
lux
S/ N
(Positi ve Im
plan t Onl y)
Photometric Efficacy & Statistical SignificancePhotometric Efficacy & Statistical Significance
. ..
1.0"
Detectability: Detectability: ((11””) Dependence via Model PSF Implantation) Dependence via Model PSF Implantation
0.01.02.0 1.0 2.0Arc Seconds
PSF FWHM = 0.16"
NICMOSF160W25 OCT 1998
Camera 2 (0.076"/pixel)Coronagraph (0.3" radius)Integration Time =1280s
TWA6 Image TWA6 Image Combination:Combination:S/NS/NTWA6B TWA6B = 35= 35
H-Band (F160W) Point-Source Detectability LimitsH-Band (F160W) Point-Source Detectability Limits Two-Roll Coronagraphic PSF Subtraction 22m Total Integration
H(5) = 7.14 + 3.15” - 0.286” 2 {M&K Stars}.
. .
9
10
11
12
13
14
15
16
0 1 2 3 4 5 6 7 8 9 10Rdiu(Acecond)
Normalized Intensity
-4 -2 0 2 4
4
2
0
-2
-4
0.0 0.2 0.4 0.6 0.8 1.0
7x7 Pixels71% Ensquared Energy
5σ
1σ
Rea
d N
oise
Dom
inat
edPh
oton
Noi
se D
omin
ated
H=6.9
0.01.02.0 1.0 2.0Arc Seconds
PSF FWHM = 0.16"
NICMOSF160W25 OCT 1998
Camera 2 (0.076"/pixel)Coronagraph (0.3" radius)Integration Time =1280s
TW Hya AssnTW Hya AssnK7K7primaryprimary, D = 55pc, D = 55pcAge = 10 MyrAge = 10 Myr
=2.54”, 140AU=2.54”, 140AUH =13.2H =13.2(L(LB/AB/A)[H]=5 )[H]=5 xx1010-6-6
Habs = 16.6Habs = 16.6
Implies:Implies:• • Mass ~ 2Mass ~ 2JupiterJupiter
• • TTeffeff ~ 800K ~ 800K
IFIF Companion... Companion...
S/NS/NTWA6B TWA6B = 35= 35
TWA 6A/BTWA 6A/B
0.01.02.0 1.0 2.0Arc Seconds
PSF FWHM = 0.16"
NICMOSF160W25 OCT 1998
Camera 2 (0.076"/pixel)Coronagraph (0.3" radius)Integration Time =1280s
Confirmation (or Rejection) by Common Proper MotionConfirmation (or Rejection) by Common Proper Motion
… … possible via ground-possible via ground-based adaptive optics based adaptive optics
imaging with a sufficiently imaging with a sufficiently long temporal baseline.long temporal baseline.
Keck II + AO imaging. Keck II + AO imaging. Courtosy of B.Macintosh, LLNLCourtosy of B.Macintosh, LLNL
Anomaly or Bias? A Jovian Planet @ Anomaly or Bias? A Jovian Planet @ >> 140 AU? 140 AU?
• RV Surveys suggest ~ 5% MS *s have 0.8—8 Mjup companions
@ d < 3AU from their primaries.
• NOT Where Giant Planets are found in our own Solar System
WHY ARE THEY THERE?
Posited*: Mutual interactions within a disk can perturb one young planet to move into a < 1AU eccentric orbit (as inferred from RV surveys), and the other…
Ejected (but bound) to very large separations, > 100AU
Cannot be observationally tested with HST-like capabilities, requires “Super-High” contrast imaging.
* e,g., Lin & Ida (ApJ, 1997); Boss (2001, IAU Symp 202)
Inner Regions of Evolved DisksInner Regions of Evolved DisksCannot yet be probed in scattered light. Yet, as inferred from mid-IR:
An inner tenuous component of warm zodi-like dust may
be confined within a few AU of HR 4796A.
12–20m thermal emission is contained completely
within the large inner “hole” of HD 141569A.
What evolutionary and dynamical interactions may be going on between What evolutionary and dynamical interactions may be going on between unseen planets and unseen dust which will shape these systems?unseen planets and unseen dust which will shape these systems?
Requires “Super-High” contrast and resolution.
0
6 7 8 9 10Log10 Age (years)
80Mjup
14Mjup
JUPITER
SATURN
STARS (Hydrogen burning)
BROWN DWARFS (Deuterium burning)
PLANETS
200Mjup
-10
-8
-6
-4
-2
Log
10 L
/Lsu
m
sun
HST Has Sampled Only the Low-Hanging Fruit HST Has Sampled Only the Low-Hanging Fruit in the in the DiskDisk//PlanetPlanet Orchard. Orchard.
GL
503.2B
GL
577B/C
CD
-33° 7795BT
WA
6B ?
HR
7329B
Anomaly or Bias? A Jovian Planet @ Anomaly or Bias? A Jovian Planet @ >> 140 AU? 140 AU?
• RV Surveys suggest ~ 5% MS *s have 0.8—8 Mjup companions
@ d < 3AU from their primaries.
• NOT Where Giant Planets are found in our own Solar System
WHY ARE THEY THERE?
Posited*: Mutual interactions within a disk can perturb one young planet to move into a < 1AU eccentric orbit (as inferred from RV surveys), and the other…
Ejected (but bound) to very large separations, > 100AU
* e,g., Lin & Ida (ApJ, 1997); Boss (2001, IAU Symp 202)
GLENN SCHNEIDERNICMOS ProjectSteward Observatory933 N. Cherry AvenueUniversity of ArizonaTucson, Arizona 85721
Phone: 520-621-5865 FAX: 520-621-1891e-mail: gschneider@as.arizona.eduhttp://nicmosis.as.arizona.edu:8000/
HUBBLE SPACE TELESCOPE
UV/Optical imaging and spectroscopy of collisionally evolved circumstellar debris and co-orbital bodies will play a pivotal role in furthering our understanding of the formation and evolution of exosolar planetary systems. To study physical processes acting over sub-AU spatial scales and time scales comparable to the age of our solar system will require a 3—4 order of magnitude improvement in instrumental stray light rejection over the performance obtainable with HST.
Is it, or Isn’t It?Is it, or Isn’t It?• Undetected in NICMOS 0.9m Followup Observation I-H > 3• Marginally Detected in 6-Orbit Binned STIS G750L Spectrum• Colors Consistent with 2 Mjup, 10 Myr, “Hot” Giant Planet
Instrument Band Bandpass Mag NICMOS/C2 F160W 1.40—1.80 20.1NICMOS/C2 F090M 0.80—1.00 >23.1 STIS/G750L I extract 0.81—0.99 ~25.4STIS/G750L R extract 0.63—0.77 >27.2
If NOT a hot young planet, it must be aHighly exotic object!
Is it, or Isn’t It?Is it, or Isn’t It?• Undetected in NICMOS 0.9m Followup Observation I-H > 3• Marginally Detected in 6-Orbit Binned STIS G750L Spectrum• Colors Consistent with 2 Mjup, 10 Myr, “Hot” Giant Planet*
. .
1 0- 5
0 . 0 0 0 1
0 . 0 0 1
0 . 0 1
0 . 1
1
1 0S y n t h e t i c S p e c t r u m : T = 8 0 0 K , 1 0 M y r , d = 1 0 p c , g = 3 x 1 0 - 4
W a v e l e n g t h ( Å )
0 . 7 0 . 8 0 . 9 1 1 . 1 1 . 2 1 . 3 1 . 4 1 . 5 1 . 6 1 . 7 1 . 8 1 . 9
F 1 6 0 WF 0 9 0 M
R e x t r a c t
I e x t r a c t
H2O
H2O
H2O
C H4
C H4
C O
C O
C H4K
H2O
C H4
H2 - H
2H
2 - H
2
20.1>23.1
~25.4
>27.2
• Keck/AO Astrometric (PM) Follow-up Thus-Far Inconclusive
* Sudarsky et al., 2000Spectrum from A. Burrows
Is it, or Isn’t It?Is it, or Isn’t It?A differential proper motion measure will be obtained with NICMOS.
If common proper motions are confirmed we will request time for NICMOS grism spectrophotometry to obtain a near-IR spectrum.
. .
1 0- 5
0 . 0 0 0 1
0 . 0 0 1
0 . 0 1
0 . 1
1
1 0S y n t h e t i c S p e c t r u m : T = 8 0 0 K , 1 0 M y r , d = 1 0 p c , g = 3 x 1 0 - 4
W a v e l e n g t h ( Å )
0 . 7 0 . 8 0 . 9 1 1 . 1 1 . 2 1 . 3 1 . 4 1 . 5 1 . 6 1 . 7 1 . 8 1 . 9
F 1 6 0 WF 0 9 0 M
R e x t r a c t
I e x t r a c t
H2O
H2O
H2O
C H4
C H4
C O
C O
C H4K
H2O
C H4
H2 - H
2H
2 - H
2
20.1>23.1
~25.4
>27.2