glenn schneider steward observatory, university of arizona (nicmos/idt) dusty circumstellar disks...

Glenn Schneider Glenn Schneider Steward Observatory, University of Arizona (NICMOS/IDT)Steward Observatory, University of Arizona (NICMOS/IDT)

Dusty Circumstellar Disks Dusty Circumstellar Disks and and

Substellar CompanionsSubstellar Companions

Glenn Schneider Glenn Schneider Steward Observatory, University of Arizona (NICMOS/IDT)Steward Observatory, University of Arizona (NICMOS/IDT)

Substellar Companions Substellar Companions and and

Dusty Circumstellar DisksDusty Circumstellar Disks

… … and, what’s happeningand, what’s happening @ ~ 100 AU?@ ~ 100 AU?

• 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

HST Provides a Unique Venue for High Contrast ImagingHST Provides a Unique Venue for High Contrast Imaging

. .

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

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

.

. .

9

10

11

12

13

14

15

16

0 1 2 3 4 5 6 7 8 9 10Radiu(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

Extra-Solar Planet &Brown Dwarf Companions

2.5"

1"

Circumstellar Disks

Scientific Areas of InvestigationScientific Areas of Investigationvia PSF-Subtracted Coronagraphic Imagingvia PSF-Subtracted Coronagraphic Imaging

HST/NICMOS Coronagphic Imaging Surveys Carried Out HST/NICMOS Coronagphic Imaging Surveys Carried Out by the IDT’s Environments of Nearby Stars (EONS) Teamby the IDT’s Environments of Nearby Stars (EONS) Team

HUBBLE SPACE TELESCOPE

DISK Candidates: 22 young (< 100 Myr) unembedded (largely unobscured by primordial material) K-A stars within ~ 100 pc with with known far-IR exceses.

PLANET/BROWNDWARF Candidates: 38 young ‘High’Proper Motion within ~ 50 pc with, including all(but one) of the then-knowMembers of the TW Hya Assn.

BROWN DWARF/VLM Star Candidates: 32 HighProper Motion Late M-Dwarf Starswithin ~ 10 pc.

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.

Collapsingprotostar

forms proto-planetary disk

Rocky coresof giant

planets form

Terrestrialplanets

form

Clearing ofinner solar

system,formation of a

Kuipercometary

belt?

106

yrs108

yrs109

yrs

accretegaseous

atmospheres

Era of heavybombarment

by comets

Currentage of

the Sun:5x109 yrs.

a PerseiSun

TW Hydrae

Taurus,Ophiuchus

star formingregions

HyadesTucanaeAssoc Pleiades

Primary Dust (≤ m) Secondary Dust (≥m)Locked to Gas Collisional erosion

Clearing Timescales: P-R drag few 106

Rad. Pressure: ~ 104

ry s107

Assoc

Giant planets

From: R. Webb

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

GL

503.2B

GL

577B/C

HR

7329B

CD

-33° 7795BT

WA

6B ?

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

DIRECT DETECTION OF YOUNG PLANETSDIRECT DETECTION OF YOUNG PLANETS

MECHANICSMECHANICS&&

A PRIME CANDIDATE (TWA 6 ‘B’)A PRIME CANDIDATE (TWA 6 ‘B’)

CORONAGRAPHICCORONAGRAPHICCOMPANIONCOMPANIONDETECTIONDETECTION

Multiaccum Imagingat two S/C orientationsIn a single visabilityperiod.

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

At=2.5” (where imageof companion emerges),background brightnessis reduced by an ADDITIONAL factorof 50 over raw coronagraphic gain (ofappx 4).

Each image of TWA6Bis S/N ~20 in differenceframe.

H companion = 20.1H = 13.2

Minimize localresiduals in region near companion image while constrainingbackground to be statistically zero...

PositivePositiveImageImageExtracionExtracion

NegativeNegativeImageImageExtractionExtraction(Inverted)(Inverted)

RotateRotateNegativeNegativeExtractionExtractionAboutAboutOccultedOccultedTargetTargetAnd AddAnd AddAfterAfterInversionInversion

Model andModel andRemoveRemoveDiffractionDiffractionSpikeSpikeResiduals*Residuals*

*DSPK*DSPK

Is it a Point Source?

Radial Profile, Photocentric Moment & Gaussian FittingRadial Profile, Photocentric Moment & Gaussian Fitting

Is it a Point Source?Is it a Point Source?

Residuals from 2D Residuals from 2D Gaussian ModelGaussian ModelSubtracted from DataSubtracted from DataAre Are IdenticalIdentical to Those to ThoseExpected from Expected from NICMOS Camera 2NICMOS Camera 2F160W PSF at the F160W PSF at the Coronagraphic Focus.Coronagraphic Focus.

How Deep?SensitivityCompleteness...

Sensitivity: Noise Equavalent Background AssessmentSensitivity: Noise Equavalent Background Assessment

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

. ..

1.0"

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

TWA6B Detection Illustrates Performance RepeatabilityTWA6B Detection Illustrates Performance Repeatability Two-Roll Coronagraphic PSF Subtraction 22m Total Integration

H(5) = 7.14 + 3.15” - 0.286” 2

.

. .

9

10

11

12

13

14

15

16

0 1 2 3 4 5 6 7 8 9 10Radiu(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

0 31 2Arc Seconds20 May 1998

NE

PSF FWHM = 0.16"NICMOS F160W

H = 6.9ΔH = 13.2ρ = 2.5"S/N = 35 TW A6"B"

0.01.02.0 1.0 2.0Arc Seconds

N

EPSF FWHM = 0.16"

NICMOSF160W

25 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

A Jovian Planet @ 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)

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?We have requested 12 HST Orbits to attempt PSF-subtracted NICMOS G141 (1.1—1.9m) grism spectrophotometry to obtain what might be the first spectrum of an extra-solar 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

This observation will also yield a Differential Proper Motion Measure.

Is it, or Isn’t It?Is it, or Isn’t It?

Time will tell…

But, if not TWA6 ‘B’, the technical capability to image such young planets is no longer in the future.

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

Dusty Disks with Radial and Hemispheric Brightness Anisotropies Dusty Disks with Radial and Hemispheric Brightness Anisotropies and Complex Morphologies, Possibly Indicative of Dynamical and Complex Morphologies, Possibly Indicative of Dynamical Interactions with Unseen Planetary Mass Companions Were Spatially Interactions with Unseen Planetary Mass Companions Were Spatially Resolved and Imaged Around Three Young (< 10 Myr) Stars.Resolved and Imaged Around Three Young (< 10 Myr) Stars.

N

E

1 "

HR 4796A (A0V), ~ 8 MyrA 70AU radius ring, ~ 10 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


TW Hya (K7) “Old” PMS Star

Pole-on circularly symmetric disk with a break in its surface brightness profile at 120 AU (2”).


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.

HR 4796AHR 4796A

1991 - Jura (ApJ, 383, L79) inferred presence of large amount of circumstellar dust from IRAS excess. Estimated dust = Ldisk/Lstar = 5x10-3 (~2x Pictoris).

1995 - Jura et al. (ApJ, 445, 451) noted earlier 110K estimate of dust temperature indicated lack of material at < 40 AU. Required grains > 3m to be bound gravitationally at 40<r<200 AU. No close companions with M* > 0.125 Msun seen (speckle).

1998 - Koerner et al. (ApJ, 503, L83) and Jayawardhana et al. (ApJ, 503, 79) independently image mid-IR disk. Inner depleted region evident in high resolution 20.8m image reproduced with a model suggesting: i=72° (+6°, -9°), PA = 28°±6°, Rin ~ 55AU, Rout ~ 80AU -> Kuiper belt-like dust ring.

1999 - Schneider et al. (ApJ, 513, L127) report on morphology and photometry of well-resolved NIR images in two NIR colors (1.1 and 1.6m) of a narrowly confined ringlike circumstellar disk, with characteristic properties predicted by Koerner et al, from ~ 0.1" resolution NICMOS coronagraphy obtained contemporaneously with 1998 mid-IR images.

Koerner et al. (1998)

Observation Model

2"

12.5 + 20.8m

20.8m

Schneider et al. (1999)

HR 4796A - Observational ChronologyHR 4796A - Observational Chronology

N

E

B

A

2"

AB = 7.7"≥500 pc

HR 4796B (late M)Likely PMS StarH, H, Ca H&K emissionJ-H = 0.75

HR 4796A - Has an M-Dwarf CompanionHR 4796A - Has an M-Dwarf Companion

… … which which couldcould help to truncate the outer portion of the disk help to truncate the outer portion of the disk

NICMOS Observations of the HR 4796A Circumstellar Debris RingNICMOS Observations of the HR 4796A Circumstellar Debris Ring

E

N

0 20 40 60 80 100

Arc

Sec

onds

(Y

)

-1.0

-0.5

0.0

0.5

1.0

0.5

-1.0

-0.5

0.0

1.00 20 40 60 80

1.5 1.0 0.5 0.0 -0.5 -1.0 -1.5Arc Seconds (X)

E

N

F160W

F110W

mJy/pixel

mJy/pixel

GEOMETRYPA = 26.8°±0.6°i = 73.1°±1.2°a = 1.05”±0.02”MORPHOLOGYr = 70AUwidth < 14AU“abrupt” truncation“clear” @ r < 50 AUFLUX DENSITY12.8±1.0mJy @ 1.1m12.5±2.0mJy @ 1.6mH(F160W) = 12.35±J(F110W) = 12.92±0.08

0.160.19

Tdust ~ Ldisk/L*

1.4±0.2x10-3 @ 1.1m2.4±0.5x10-3 @ 1.6mNIR scattered flux in goodagreement with visible absorption & mid-IR re-radiation.

E

N

0 20 40 60 80 100

Arc

Sec

onds

(Y

)

-1.0

-0.5

0.0

0.5

1.0

0.5

-1.0

-0.5

0.0

1.00 20 40 60 80

1.5 1.0 0.5 0.0 -0.5 -1.0 -1.5Arc Seconds (X)

E

N

F160W

F110W

mJy/pixel

mJy/pixel

0 20 40 60 80 100

E

N

ImplicationsPossible dynamicalconfinement of particles byone or more unseen bodies.

Mean particle size > few m.debris origin, not I.S. dust.

AnisotropiesNE ansa ~ 15% brighter than SW ansa.

Suggestion of preferential(forward) scattering to SE.

NICMOS Observations of the HR 4796A Circumstellar Debris RingNICMOS Observations of the HR 4796A Circumstellar Debris Ring

Deep OSCIR images of the HR 4796A disk Telesco et al. (1999, A&A) indicate comparable sizes of 10.8 and 18.2 m emitting regions. They find central zone ≤ 3% of main part of the disk (confirming that the central hole is largely cleared). Inward fall-off from the ring is shallower at 18.2m then inferred from the NICMOS images. Moreover, they report on a possible brightness asymmetry in the OSCIR images (similar to NICMOS) which might implicate the existence of a gravitational perturber causing this "pericenter glow" (Wyatt, et al 2000) from particles in the NE side of the disk shifted closer to the star.

0 20 40 60 80 100

E

N

Arc Seconds-2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0

1.0

0.5

0.0

-0.5

-1.0

E

N

-1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0

0 20 40 60 80 100

-2.0

Top: OSCIR 18.2 m Bottom: NICMOS 1.1 m

Star-subtracted scansalong the disk major axis.

Models for different grainsizes (Telesco, et al. 1999)

HR 4796A - Thermal IR ImagingHR 4796A - Thermal IR Imaging

NICMOS

N

E

1 "

Additional processing recovered ring flux closer in and suggested somewhathigher inclination (~76°).

“Clumpiness” due to residuals in PSF subtraction, not attributed to structure of ring.

1999 - Greaves et al. obtain JCMT/SCUBA 450 and 850m flux excess measures of 0.18 and 0.019 Jy, respectively, and estimate total gas mass < 1–7 Earth masses.

1999 - Augereau et al. re-reduce K' observations of Mouillet et al. and find excess in agreement with Schneider et al at ~1" in low S/N image showing extension in NE/SW directions. They estimate a lower limit for dust mass of ~ 4 Earth masses.

HR 4796A - Observational ChronologyHR 4796A - Observational Chronology

z=0.5AU, R=5AU, NIR=0.25

z=5AU, R=10AU, NIR=0.2 z=1AU, R=20AU, NIR=0.1

NICMOS 1.1m image

Monte Carlo runs constrain geometry & dustProduce observed dust distibution in 10 MyrMinitial: 10-20x minimum-mass solar nebulaAssume: isotropic scattering and, = 0.3 (Augereau et al, 1999)Adust to obtain ~ 1.5x10-3

ae0 = 10-3

e0 = 10-3

m0 = 10MMSN

CONCLUSIONS:• Planet formation @ 70 AU in 10 Myr possible with initialdisk mass =10—20MMMSN.

• Dust production associated with planet formation is thenconfined to a ring with a = 7—15 AU.

• Optical depth in ring satisfies constraints on scattered lightat 1—2 m and on thermal emission at 10—100 m if thedust size distribution is N ~ ri with q ≥ 3 for ri ≤ 1 m.

• Models with disk masses smaller than 10MMSN fail toproduce planets and an observable dusty ring in 10 Myr.

-q

Kenyon & Luu (1999, ApJ)

HR 4796A - Kenyon & Wood (2000) Dynamical Evolutionary ModelHR 4796A - Kenyon & Wood (2000) Dynamical Evolutionary Model

Cold annulus + hot dust (~0.2Jy)

Simulated disk at 20.8m,assuming grain properties andsurface density derived fromthe SED fitting and a Piclike vertical structure, with0.14" pixels like observationsby Koerner et al. (1998) andconvolved 10m telescope PSF.

Full SED fitting withtwo dust populations.

HR 4796A - Augereau et al. (1999) Physical ModelHR 4796A - Augereau et al. (1999) Physical Model

Simulatated images of the cold annulus peaked at 70 AU inscattered light at 1.1m (with 0.076" pixels as in NICMOS)for two asymmetry factors considered assuming a Henyey-Greenstein phase function (The inner hot dust not observablehas not been added). The NICMOS observation suggests |g| <0.15. The flux density predicted in the region outside r > 0.65"is 5.2mJy, in good agreement with the 7.5±0.5mJy observedwith HST.

Two-component model reproduces all then-available observations: "the full spectral energy distribution from the mid-infrared to the millimeter wavelengths, resolved scattered light and thermal emission observations".

a) cold amorphous (Si and H20 ice) grains > 10m in size (cut-off in size by radiation pressure), with porosity ~0.6, peaking at 70AU.

b) hot dust at ~ 9AU of "comet-like" composition (crysatlline Si and H20), porosity ~ 0.97.

Collisions are common in both populations. Bodies as large as a few meters are required.

Model gives rise to a minimum massof a few Mearth with gas:dust < 1.

~0.2Jy

cold annulus+hot dust

HR 4796AHR 4796AThe quest for The quest for

higher resolutionhigher resolution

HR

479

6AH

R 4

748

(PS

F)

Orient #1 Orient #2

Orient = 16°

STIS Observations of the HR 4796A Circumstellar Debris RingSTIS Observations of the HR 4796A Circumstellar Debris Ring

HR

479

6AH

R 4

748

(PS

F)

Orient #1 Orient #2

_


BetterFocus

Match

BetterFocusMatch

PSF Orient #1 PSF Orient #2

Varience Minimized (Flux & Position Adjusted) PSF Subtractions

BetterPositionMatch

BetterPosition

Match


PSF Orient #1 PSF Orient #2

N

E

2-rollssamplesregions

otherwiseobscuredby wedge& spikes


Varience Minimized (Flux & Position Adjusted) PSF Subtractions

Weighted Image Combination - Resampled

N

E

1 "

-20 0 20 40 60 80 100% of Peak (NE Ansa) Surface Brightness


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 = 0.192”

FWHM: 12.9±0.7AU 9.6% Dring

1-e-1 = 0.126”

PSF point source = 0.043”Measured = 0.197”

WIDTH AT NE ANSA

1-e-1: 7.5±0.4AU 11.9% Rring

*

Slightly asymmetric

*

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

0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0

% P e a k ( N E ) A n s a l F l u x

Spatially Resolved Relative PHOTOMETRY of the RingSpatially Resolved Relative PHOTOMETRY of the Ring

. .

0.5 1.0 1.5Radius (arcseconds)

02468

10

-2-4-6-8

-10

Photometric Error EstimationPhotometric Error Estimation

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

STIS(eff 0.58 m): F(ring[unobscured])/F(star) = 0.00049 ± 0.000036 (7.3%)NICMOS (eff 1.10 m): F(ring[unobscured])/F(star) = 0.00083 ± 0.00012 (14.3%)

Aperture PhotometryAperture Photometry

NICMOS (eff 1.60 m): F(ring[unobscured])/F(star) = 0.00140 ± 0.00029 (20.8%)

Wavelength Dependent Scattering Efficiency (Color)Wavelength Dependent Scattering Efficiency (Color)

HR 4796A SUMMARYHR 4796A SUMMARY Ring geometry/astrometry defined by NICMOS improved by higher resolution STIS observations. Notably, i 2.6° larger than original (published) NICMOS solution.

“Left/Right” brightness anisotropy or ~20% along at least 50° wide diametrically opposed arcs centered on ansae.

“Front/Back” brightness anisotropy, roughly symmetric in both L/R “hemispheres”, increasing with longitudinal distance from ansae to 35% difference at 30° from ansae.

Characteristic width ~ 10% of 70AU radius ring.

Ring is uniformly RED from “V” to H with 1:1.7:2.9 spectral reflectance in CCD50(“V”):F110W(1.1m):F160W(H).

Spatially resolved photometry of ring with ±2% uncertainty at ansae (1”), and ±6—8% uncertainty at 0.6—0.5”.

0 10 20 30 40 50 60 70 80 90 100% Peak Surface Brightness

1"N

E

NICMOS F110W (0.8—1.4m)STIS50CCD(0.2—1.0m)

Brightness Anisotropies, Confinement & ColorBrightness Anisotropies, Confinement & ColorConsistent with Dynamical Interactions withConsistent with Dynamical Interactions with

Co-Orbital Unseen Planet-Mass BodiesCo-Orbital Unseen Planet-Mass Bodies

HD 141569AHD 141569A

1"

HD 141569 PSF STAR12

.517

.920

.8

0.26" FWHM

0.37" FWHM

0.43" FWHM

HD 141569A - Thermal IR Disk Detected/Imaged by SilverstoneHD 141569A - Thermal IR Disk Detected/Imaged by Silverstone

B9V Herbig Ae/Be Star, H = 6.89d = 100 pc, Age ~ 5 Myr, 2.3Msun

1" Face-on ProjectionUnsharp Masking Gradient Enhancement

1.1m NICMOS Coronagraphic Image

Disk Radius = 400 AUGap Radius = 245 AUGap Width ~ 40 AU

HD 141569A - NICMOS Coronagraphic ImagingHD 141569A - NICMOS Coronagraphic Imaging

Scattering by cold dust is OUTSIDE region of thermal emission.

Surface Density of Scatterers

100 200 300 400 500Radius (AU)

0.01

x

500AU (5")

NICMOS F110W

HD 141569A - Circumstellar Disk & GapHD 141569A - Circumstellar Disk & Gap

Total Flux Density = 8±2mJy @ r>0.6”Peak SB = 0.3mJy arcsec-2 @ 185AU

Inclination to LOS = 51°±3°

Intrinsic Scattering Function results inBrightness Anisotropy in ratio 1.5±0.2:1in direction of forward scattering.

Gap may be partially cleared of materialby unseen planetary companion.

Gap Width:Radius implies planetary mass of ~ 1.2 M jup (2Mjup detection limit @ gap, where w=0.35±0.05).

Hieracrchial triple system dA(BC) = 8.3”, dBC = 1.3” (projected)M-Dwarf companions may influence disk dynamics.

DENSITY OF SCATTERERS

= 4r2F(r)

= albedo

= optical depth to scattering

But, in the outer portion of disk:absorbed < 8.4x10-3 ==> scattered ~ 0.4

total= scattered + absorbed

If scattered + absorbed = LIR/L = 8.4x10-3,then scattered = scattered/total = 0.25

*

(Weinberger, et al., 1999)

HD 141569A - Albedo of the GrainsHD 141569A - Albedo of the Grains

Locationof gap

R = 240 AU, M = 2.3Msun, so P = 2450 yr. For Age = 5x10 6 -> 2000 orbits

Limiting F110W magnitude for a point source in the gap is 20.3 -> M ~ 3 jup

Mass of Planet to Clear Gap: M/M* ~ c(a/a3) where c~ 0.1 (Lissauer 1993)for a = 50 AU, a = 240 AU -> M = 0.9 Mjup, below detection threshold.

Note: For a gaseous disk (not this case) time to clear gap ~ 300 orbits (Lin et al 1999).

HD 141569A - Can a Planet “Hide” in the Gap?HD 141569A - Can a Planet “Hide” in the Gap?

A – BSep = 7.”57PA = 311.5°

B – CSep = 1.”38PA = 301.9°

1998 NICMOS1934 Rossiter

DifferentialProper Motions

0

1

2

3

4

5

6

7

8

0 1 2 3 4 5 6 7 8

Arcseconds (West)

Arc

seco

nds

(Nor

th)

Predicted 1998 position from 1934measures and Hipparcos proper motions

Also, consistent radial velocities==> Common Space Motion

(Weinberger, et al, 2000, ApJ)

HD 141569 (A, BC)- A Triple SystemHD 141569 (A, BC)- A Triple System

TiOLi I

Ha

Flu

x D

ensi

ty (

x10

3)

5

0

10

15

6400 6600 6800 7000 7200 7400

B

A

0.50± 0.05

-1.70± 0.05

C

0.50± 0.05

-0.50± 0.05

B

Li

HaEW

HD 141569 B & C ~ 5 Myr ± 3

Spectral Types: B = M2V, C= M4V

Companions: Young, Hot, M-Dwarfs

.

16

8

6.3

43.2

2 0.80.7

0.6

0.50.45

0.35

0.25

0.2

0.15

3.503.60 3.55Teff

6

7

5

4

3

C

Baraffe, et al. (1998)

HD 141569 (A, BC)- Age-Dating the SystemHD 141569 (A, BC)- Age-Dating the System

2

3

4

56789

• Density of Scatters:

Equal at 200 AU and 360 AU.

If non-coplaner companions can

excite vertical velocities in disk.

• Circular 50 AU-wide Gap @ 250AU

Continual clearing to remove P-R

and RP driven transiting particles.

• Gap circularity implies dynamical

stability on long time-scales.

• If co-planer Lindblad resonances

from 1053AU distant CoM (BC)

(9:1) @ 243 AU, (8:1) @ 263AU

closest to gap.

HD 141569 (A, BC) - Dynamical Sculpting by Companions?HD 141569 (A, BC) - Dynamical Sculpting by Companions?

HD 141569AHD 141569ANICMOS (0.11” Resolution)NICMOS (0.11” Resolution)

Knowing the Flux Desnisity, Orientation, Size, etc.,Allowed Planning an Effective Follow-up...

HD 141569AHD 141569ASTIS (0.05” Resolution)STIS (0.05” Resolution)

Global strcture better described by “concentric ring” morphology.

“Gap” broader and partially filled.

“Spiral arclett” structure seen in disk gap.

HD 141569AHD 141569A NICMOS (0.11”) STIS (0.05” )NICMOS (0.11”) STIS (0.05” )

Gradient EnhancementGradient Enhancement+ Mild Smoothing (@ Pixel Scale)+ Mild Smoothing (@ Pixel Scale)

TW HydraeTW Hydrae

• K7Ve (Rucinski & Krautter, 1983)

• Distance: 56±7 pc (Hipparchos)

• Age: ~ 6 Myr

• Ha and UV Excesses

Isolated Classical T-Tauri Star

• Member TW Hya Association

(TWA ~ 10 Myr, 60 pc)

• Long Wavelength Excesses

~ Ldisk/Lstar ~ 0.3 (IRAS)

CO emission (Zuckerman et al. 1995)

TW HydraeTW Hydrae

• Gray scattering: F110W - F160W = 0.96 mag (same as star)

Flared Disk + Hole

Thin Disk

1.1m 1.6m

ln Surface Brightness (mJy arcsec-2)

TW Hydrae - NICMOS Coronagraphic ImagingTW Hydrae - NICMOS Coronagraphic Imaging Face-On, Optically Thick, 190 AU radius Flared Disk

0

2

4

6

8

-2

8

6

4

2

0

-21 2 30

RADIUS (arc seconds)

SUR

FA

CE

BR

IGH

TN

ES

S (m

Jy a

rcse

c-2)

TW Hydrae - Is it Real?TW Hydrae - Is it Real?

YESYES

TW Hydrae - Is it Real?TW Hydrae - Is it Real?

YESYES

Also seen in HST Optical Band-Passes

STIS (0.5m) WFPC-2 (0.8m)

TW Hydrae - Surface Brightness Profile TW Hydrae - Surface Brightness Profile Flux density Power Law: r-2.6±.0.1 @ 35 AU < r < 135 AU

Break @ 100 AU

TW Hydrae - Surface Brightness Profile TW Hydrae - Surface Brightness Profile

Sur

face

Bri

ghtn

ess

(ma g

arc

s ec-2

)12

14

16

18

20

22

0.6 0.8 1 32 4Radius (Arc Seconds)

F160WF110WF814WF606W50CCD (uncalibrated)

Zone 1 2 3 4

NICMOS - Weinberger et al. 1999WFPC-2 - Krist et al. 2000

“Zone 2-3 Break” may implicate sculpting by grains

Radially and azimuthally confined arc-like depression?

TW Hydrae - Optical Assymetry TW Hydrae - Optical Assymetry

AB

SO

LU

TE

MA

GN

ITU

DE

50 100 1500RADIUS (AU)

1 Mjup

3 Mjup

7 Mjup

10 Mjup

10

12

14

16

18

TW Hydrae - Companion Detection Limits TW Hydrae - Companion Detection Limits

8 9 10 11 12 13

0.0

0.2

0.4

0.6

0.8

1.0Peak: Amorphous (~9.6m) & Crystaline (~11.2m) Silicates.

TW Hydrae - Mid-IR (8—13TW Hydrae - Mid-IR (8—13m) Spectrumm) Spectrum(Spatially Unresolved @11.7 & 17.9 (Spatially Unresolved @11.7 & 17.9 m) m)

Wavelength (microns)

Fn (J

y)

Keck I LWS ~ 120Weinberger, Becklin, Schneider, 2001

1 10 100 1000 10000

-9

-10

-11

-12

-13

-14

-15

Log

F

[erg

s-1 c

m-2]

Wavelength [microns]

TW Hydrae - SED Model from All Spectral Bands TW Hydrae - SED Model from All Spectral Bands

ala Chaing et al. (2001)

Surface grains < 2mInterior grains < 12mm

Grain Size Distribution dN/dr (interior) ~ r-1

dN/dr (surface) ~ r-3.5

Dust Surface Mass Density 10 (r/AU) -1 cm-2

Disk Radii: Inner = 0.05 AU Outer = 200 AU

TW Hydrae - SummaryTW Hydrae - SummaryTTS surrounded by Optically Thick dust disk.Disk must be Flared given scattered light radius and thermal SED.

“Break” in Surf. Brightness @ ~ 95AU may be due to dynamical effects.

No Companions found to 10—2 Mjup @ 40—100 AU limit.

Disk Mass: ~ few x102 Earth Masses of Condensed Silicates & Ices.

Dust mass few times > “typical” Taurus & Ophiuchus TTS Disks.

Good evidence for grain growth within the disk.

HD 141569

490 AU

370 AU

800 AU

PEAKGAP

TW HYDRAE

300 AUTWA6 A/B

HR 4796A

140 AU

140 AU

PHYSICAL SIZESPHYSICAL SIZES

HD 141569

490 AU

370 AU

800 AU

PEAKGAP

TW HYDRAE

300 AUTWA6 A/B

HR 4796A

140 AU

140 AU

The first-epoch NICMOS mission The first-epoch NICMOS mission ended on 4 January 1999. But, just as ended on 4 January 1999. But, just as dust is reprocessed around young stars, dust is reprocessed around young stars, NICMOS will get a new lease on life NICMOS will get a new lease on life after HST SM3B (14 Feb 2002) when a after HST SM3B (14 Feb 2002) when a a reverse Brayton cycle cooler will be a reverse Brayton cycle cooler will be installed and interfaced with NICMOS, installed and interfaced with NICMOS, returning it to service.returning it to service.


We look forward toWe look forward tothe re-incarnationthe re-incarnationof NICMOS, toof NICMOS, tocontinue the search.continue the search.

QuickTime™ and aSorenson Video decompressorare needed to see this picture.

Today, we have only a handful of Today, we have only a handful of spatially resolved images of dusty spatially resolved images of dusty debris disks and extra-solar debris disks and extra-solar planet companion planet companion candiates. candiates.

GLENN SCHNEIDERNICMOS ProjectSteward Observatory933 N. Cherry AvenueUniversity of ArizonaTucson, Arizona 85721

Phone: 520-621-5865FAX: 520-621-1891e-mail: [email protected]://nicmosis.as.arizona.edu:8000/


glenn schneider steward observatory, university of arizona (nicmos/idt) dusty circumstellar disks...

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