Post on 20-Jan-2016
description
From Molecular Cores to Planet-From Molecular Cores to Planet-forming Disks: Overview and forming Disks: Overview and
Recent Results from the Spitzer Recent Results from the Spitzer Space TelescopeSpace Telescope
Neal J. Evans IINeal J. Evans II
University of Texas at AustinUniversity of Texas at Austin
and the c2d Teamand the c2d Team
From Cores to Disks (c2d)From Cores to Disks (c2d)
Science GoalsScience Goals
Complete database for nearby (< 350 pc), Low Complete database for nearby (< 350 pc), Low mass star and substar formationmass star and substar formation
Follow evolution from starless cores to planet-Follow evolution from starless cores to planet-forming disksforming disks
Coordinate with FEPS team to ensure complete Coordinate with FEPS team to ensure complete coverage of 0 to 1 Gyrcoverage of 0 to 1 Gyr
Cover range of other variables (mass, rotation, Cover range of other variables (mass, rotation, turbulence, environment, …) to separate from turbulence, environment, …) to separate from evolution.evolution.
ObservationsObservations (275 hr) IRAC and MIPS Mapping(275 hr) IRAC and MIPS Mapping
Map ~5 large clouds (~20 sq. deg.) Map ~5 large clouds (~20 sq. deg.) ~135 smaller cores ~135 smaller cores
(50 hr) IRAC and MIPS Photometry(50 hr) IRAC and MIPS Photometry ~190 stars~190 stars
(75 hr) Spectroscopy of disk material (IRS) (75 hr) Spectroscopy of disk material (IRS) about 200 targetsabout 200 targets
Ancillary/complementary data from optical to mmAncillary/complementary data from optical to mm Collecting a very large data baseCollecting a very large data base Will be publicly available eventuallyWill be publicly available eventually
Early Results from SpitzerEarly Results from Spitzer
Mostly validation data (about 1% of total)Mostly validation data (about 1% of total) Observed two small cores (IRAC/MIPS)Observed two small cores (IRAC/MIPS)
• One (L1228) with a known infrared sourceOne (L1228) with a known infrared source• One (L1014) withoutOne (L1014) without
Observed six IRS targetsObserved six IRS targets• B5 IRSB5 IRS• HH46/47 IRS (with ERO team)HH46/47 IRS (with ERO team)
Recently received data (little analysis done) Recently received data (little analysis done) Ophiuchus, a few coresOphiuchus, a few cores
A Typical Starless CoreA Typical Starless Core
L1014 distance ~ 200 pc, but L1014 distance ~ 200 pc, but somewhat uncertain. somewhat uncertain.
R-band image from DSSR-band image from DSS
A Surprise from SpitzerA Surprise from Spitzer
Three Color Composite:Three Color Composite:Blue = 3.6 micronsBlue = 3.6 micronsGreen = 8.0 micronsGreen = 8.0 micronsRed = 24 micronsRed = 24 microns
R-band image from DSS atR-band image from DSS atLower left.Lower left.
We see many stars through We see many stars through the cloud not seen in R.the cloud not seen in R.The central source is NOT The central source is NOT a background star. a background star.
L1014 is not “source-less”.L1014 is not “source-less”.Larger size in red is PSF.Larger size in red is PSF.
C. Young et al. ApJS, in press
Source Peaks on mm EmissionSource Peaks on mm Emission
Left: 8 micron on 1.2 mm MAMBO dust continuum emission (Kauffmann & Bertoldi)Left: 8 micron on 1.2 mm MAMBO dust continuum emission (Kauffmann & Bertoldi)Right: 24 micron on 850 micron SCUBA data (Visser et al. 2002)Right: 24 micron on 850 micron SCUBA data (Visser et al. 2002)
Both long-waveBoth long-wavemaps are 3-sigma maps are 3-sigma contours.contours.
C. Young et al. ApJS, in press
ModelsModels
C. Young et al. ApJS, in press, Poster 41.15
Model of SED for d = 200 pc.Model of SED for d = 200 pc.Central object has very low Central object has very low luminosity: 0.09 Lluminosity: 0.09 Lsunsun..
Requires BB plus diskRequires BB plus disk(red line) in an envelope.(red line) in an envelope.M(envelope) about 2 MM(envelope) about 2 Msunsun..
Cannot be a stellar-mass Cannot be a stellar-mass object with significant object with significant accretion. Probably sub-accretion. Probably sub-stellar at this point.stellar at this point.
Alternative model: more Alternative model: more distant (2.6 kpc) object lined distant (2.6 kpc) object lined up by chance with peak of a up by chance with peak of a foreground core (dashed line)foreground core (dashed line)
Lessons from L1014Lessons from L1014
““Starless” cores may not beStarless” cores may not be Or may have substellar objectsOr may have substellar objects
Very low luminosity sources may existVery low luminosity sources may exist Must be low mass and low accretionMust be low mass and low accretion Caveat: possible background sourceCaveat: possible background source
Are there others?Are there others?
Check the Thumbprint Check the Thumbprint
Another “starless” core, the thumbprint nebula. Has scattered light Another “starless” core, the thumbprint nebula. Has scattered light all around periphery. Barely detected with ISO; consistent with all around periphery. Barely detected with ISO; consistent with heating only by the ISRF. See Lehtinen et al. 1998, Astr. Ap. heating only by the ISRF. See Lehtinen et al. 1998, Astr. Ap. 333,702.333,702.
Another clue?Another clue?
Blue is DSS-red, green is 24 microns, red is 70 Blue is DSS-red, green is 24 microns, red is 70 microns MIPS data are very preliminary, not cleaned microns MIPS data are very preliminary, not cleaned up. IRAC not available yet.up. IRAC not available yet.
HH46/47 Outflow StructureHH46/47 Outflow Structure
Noriega-Crespo et al. ApJS, in press
Shock SpectrumShock Spectrum
Noriega-Crespo et al. ApJS, in press
Icy Dust GrainsIcy Dust Grains
Boogert et al. ApJS, in press
Spitzer IRS plus Keck/NIRSPEC or VLT/ISAACSpitzer IRS plus Keck/NIRSPEC or VLT/ISAAC
Rich spectrum of ices:Rich spectrum of ices:COCO22, H, H22O, CHO, CH33OH, OCNOH, OCN––
and others.and others.
Can study ice evolution Can study ice evolution in regions forming sun-in regions forming sun-like stars. Little like stars. Little processing at T>50 K, processing at T>50 K, some evidence for lower some evidence for lower temperature processing.temperature processing.
Ices in low-mass starsIces in low-mass stars
Spectral EvolutionSpectral Evolution
10 My10 My
100 My100 My
5 Gy5 Gy
Few MyFew My
C2D IRS Validation DataC2D IRS Validation Data
Band positions, not ID
CO2
H2OCH3OH+?
Silicates
Silicates
NH3
CH4
CH3OH+?
PAH PAH E/F EE EE
E F F F FE/F F F
FeO
PAH PAH PAHPAH/F E/F E
Silicates Silicates
PAH?
PAHE/F
EEF
FF
F E/FF
F
FeO
PAHPAH
PAH
SilicatesSilicates
F
Debris Disks around wTTSDebris Disks around wTTS
Model has 0.1 MModel has 0.1 Mmoonmoon of of
30 30 m size dust grainsm size dust grainsin a disk from 30–60 AUin a disk from 30–60 AUBars are 3 Bars are 3 Model based on disksModel based on disksaround A starsaround A stars
Not enough data yet Not enough data yet to say anything.to say anything.
A Surprise from the wTTsA Surprise from the wTTs
RXJ1301.0-7654 RXJ1301.0-7654 Move from DSS to 24 Move from DSS to 24 microns in steps.microns in steps.Nondescript nearby Nondescript nearby star on DSS is the star on DSS is the strong one at 24 strong one at 24 microns. Which is the microns. Which is the X-ray source?X-ray source?
Very Recent DataVery Recent Data
Preliminary reductionPreliminary reduction Minimal analysisMinimal analysis
Ophiuchus AOphiuchus AVV = 3 and AORs = 3 and AORs
Outline of AOutline of AVV = 3 = 3
IRAC IRAC AORSAORS
MIPS MIPS AORsAORs
11oo
L1689 at 24 micronsL1689 at 24 microns
High-extinction regions are High-extinction regions are dark at 24 micronsdark at 24 microns
Red: 24 micron emission, Blue: extinction from 2MASS and Red: 24 micron emission, Blue: extinction from 2MASS and Weingartner and Draine extinction law, binned to 40” resolution.Weingartner and Draine extinction law, binned to 40” resolution.
Cuts: Black is Cuts: Black is AAVV; Red is ; Red is
emissionemission
IRAC on L1689IRAC on L1689
Blue is IRAC-1 (3.6); Green is IRAC-2 (4.5); Red is IRAC-4 Blue is IRAC-1 (3.6); Green is IRAC-2 (4.5); Red is IRAC-4 (8) Extremely preliminary, obtained data a few days ago.(8) Extremely preliminary, obtained data a few days ago.
Bolocam map of OphiuchusBolocam map of Ophiuchus
K. Young et al. In prep
Bolocam map (1.2 mm) Bolocam map (1.2 mm) of region in Spitzer of region in Spitzer survey. Covers very survey. Covers very large area (> 10 sq. large area (> 10 sq. deg.) compared to any deg.) compared to any previous map. previous map. Rms noise ~ 50 mJy, Rms noise ~ 50 mJy, with about half the with about half the data.data.
CG30/31 CoresCG30/31 Cores
Collection of cores in the Gum nebula (d ~ 200 pc).Collection of cores in the Gum nebula (d ~ 200 pc).
MIPS-24MIPS-24
MIPS-70MIPS-70
Color CompositeColor Composite
Blue is DSS-redBlue is DSS-redGreen is 24 micronsGreen is 24 micronsRed is 70 micronsRed is 70 microns
Very preliminary Very preliminary reduction. No IRAC reduction. No IRAC data available yet.data available yet.
Lots more to come…Lots more to come…
Maps of Chamaeleon, Serpens deliveredMaps of Chamaeleon, Serpens delivered Working on dataWorking on data
About 20 small cores observedAbout 20 small cores observed Other clouds, many small coresOther clouds, many small cores Photometry of starsPhotometry of stars IRS targetsIRS targets