INTRODUCTIONJoan Najita National Optical Astronomy Observatory John Carr Naval Research Laboratory...
Transcript of INTRODUCTIONJoan Najita National Optical Astronomy Observatory John Carr Naval Research Laboratory...
-
PProbing Planet Forming Disks:Clues to the Origins of Planetary Systems
INTRODUCTIONJoan Najita
National Optical Astronomy Observatory
John CarrNaval Research Laboratory
Matt RichterUC Davis
High Resolution MIR Spectroscopy of Planet Formation Environments
-
My Main Points
Forming planetary systems have a rich MIR spectrum•Discovered in the last 2 years (Spitzer + ground)•Emission and absorption
Observations address major Origins questions•Origin of prebiotic molecules and life•What kind of planets form in what kinds of disks?•Do stars form via dynamical infall?
Large discovery space (unanticipated science)
-
Origin of Prebiotic Molecules and Life
Were the “chemical building blocks” oflife delivered to Earth by asteroids andcomets?What prebiotics are synthesized in disks?
Complex hydrocarbonsAmino acidsRNA
-
What kind of disks form what kind of planets?
Low mass Jovian planet: Gap High mass Jovian planet: hole
Structure of gaseous disk more definitive than SEDsin identifying forming planets
Connecting initial conditions (e.g., disk mass) to outcomes (planetproperties) provides direct constraints on planet formation theories
-
Molecular Probes of Inner Disks
0.1 AU~1000 K
1 AU~200 K
10 AU~50 K
H2O ro-vib
CO Δv=2
CO Δv=1
H2 UV, NIR, MIR
OH Δv=1 HCN, CO2C2H2, OH, H2ONH3
Rich MIR spectrum probes the planet formation region
-
S/N ∼ 250Atomic lines [NeII], HIMolecules C2H2, HCN, CO2
H2O, OH
Carr & Najita (2008)
Spitzer IRS Spectrum of a Typical T Tauri Star
-
Molecular Emission is Common, Diverse
C2H2 CO2HCN•Relative strengths of molecularfeatures vary.
•Abundances are diverse.
log (HCN/H2O)
log
(CO
2/H 2
O)
T Tauri stars
Comets
-
H2O Rotational Emission Line Resolved
13µm
Line profiles, temperatures, and emitting areas indicateorigin in planet formation region of disk
Water emission resolved:90 km/s FWHMFrom r = 0.3--1 AU
H2O (12,8,5)—(11,5,6)
Gemini/TEXES R=100,000
Carr, Knez, Richter, Knez et al.
Spitzer/IRS R=600
-
MIR Molecular Emission
Rich emission from planet formation region:• Organics, water, atomic emission is common• Relative molecular abundances are diverse
Spectroscopy of multiple lines measures vs. disk radius• Temperature• Column density, and• Abundances
This basic technique enables a wide range of studies(disk dynamics, structure, chemistry).
-
Spitzer MIR Molecular Absorption
Nearby T Tauri Starw/ edge-on diskobserved with Spitzer/IRS
Absorption in gaseousHCN, C2H2, CO2
Courtesy: Spitzer IRS GTOs
-
MIR Molecular Absorption: High Res
Gemini/TEXES (R=100,000)FWZI ~ 20 km/s
Can detect molecules w/ostrong bands that Spitzerdoes not detect
NH3 NH3NH3
C2H2 HCN
-
MIR Molecular Absorption
High spectral resolution needed to know if absorption in…•Disk atmosphere (narrow, at zero velocity)?
•Infall from cloud core (redshifted)? •Wind (blueshifted)?
Abundances and column densities of each are interesting.•Disk: rarer species detectable, complements emission
•Infall: detection, measure infall rate and abundances
•Wind: disk wind or X-wind?
-
Molecular Inventories
Pre-InfallDisksCometsRelative
Abundances
8100100100100100H2O
Orion HotCore
Inner DiskAtmospheres
Hale-BoppHyakutakeHalley
Starting to probe molecularprocessing in disks!
-
MIR Accessible MoleculesH2H2O waterHDOH2O2OHSiOOCSSO2H2SSiSH2CO formaldehydeCH4 methaneCH3D CH3 methyl radicalC2H2 acetylene HCN hydrogen cyanideHNCO isocyanic acidNH3 ammonia
C2H4 ethyleneC2H6 ethaneC4H2C6H2 C3H8 propaneCH2CCH2 propadieneC6H6 benzeneHCOOH formic acidCH3OH methanolHN2CHO formamideHC3CHO acetaldehydeCH3COOH acetic acidHCOOCH3 methyl formateCH2OHCHO glycoaldehydeC2H5OH ethanol(CH3)2CO acetoneHOCH2CH2OH ethylene glycolNH2CH2COOH glycine
Detected with TEXES
-
Future MIR Science•Search for prebiotic molecules in disks, infall
•High res GSMT spectra resolves blends, measures disk radii
•Search for evidence of planetesimal and protoplanet formation using disk abundances. (NEW!)
•GSMT line profiles establish inner disk origin for bright srcs•JWST measures H2O+organics abundances for large samples
•Search for disk gaps created by forming giant planets.•GSMT line profiles measure column density deficits
•NeII 12.8µm as a probe of disk gas lifetime (constrains giant and terrestrial planet formation theories).
•GSMT line profiles measure disk radii probed by NeII•JWST surveys large samples for NeII flux
-
GSMT and Precursor StudiesTEXES/Gemini or VISIR/VLT:• study bright emission lines in isolated environments (NeII, water w/in 150 pc)• absorption in a few bright sources
High Resolution MIR Spectroscopy with GSMT:• search for rarer molecules w/in 150 pc• study bright emission (water, NeII) in high mass star environments (out to 500 pc)• absorption in a real sample
Pathfinding studies possible now, but GSMT sensitivityneeded for the most significant discoveries
-
Synergy of JWST, ALMA, and GSMT
JWST/MIRI high spectral resolution (R=3000) important:• resolve some blends, detect weaker lines (not just water)• individual lines not resolved
R=100,000 Spectroscopy with GSMT•resolve blends, detect weak features•Separate disk, infall, winds with line profile shape•Measure column density and abundance vs. radius
ALMA studies cooler gas at larger disk radii
-
GSMT Requirements forHigh Resolution MIR Spectroscopy
•Large wavelength coverage•Queue scheduling (water vapor, Doppler shifts)for some transitions
-
Observations address major Origins questions•Origin of prebiotic molecules and life•What kind of planets form in what kinds of disks?•Do stars form via dynamical infall?
Large discovery space (unanticipated science)
My Main Points
Planet forming systems have a rich MIR spectrum
•MIR a desert “in bloom”•Emission and absorption