Post on 13-Jan-2016
description
11
Atmospheric dynamics of red supergiant stars
Andrea ChiavassaGroupe de Recherche en Astronomie et
Astrophysique du LanguedocGRAAL
Thesis advisor: Bertrand Plez
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OutlineOutline
RSG starsRSG stars The modeller's point of view The modeller's point of view The virtual observer’s point of viewThe virtual observer’s point of view SpectroscopySpectroscopy InterferometryInterferometry Conclusions et perspectivesConclusions et perspectives
33
OutlineOutline
RSG starsRSG stars The modeller's point of view The modeller's point of view The virtual observer’s point of viewThe virtual observer’s point of view SpectroscopySpectroscopy InterferometryInterferometry Conclusions et perspectivesConclusions et perspectives
44
RSG stars - 1RSG stars - 1
Meynet & Maeder, 2003
RRSG 500 - 1000 Rsun
10 < MRSG < 30 Msun
3450 K < TRSG < 4100K(Levesque et al., 2005)
55
RSG stars - 2RSG stars - 2
RSGs:RSGs:
- are irregular, small-are irregular, small-amplitude variablesamplitude variables
- strong molecular bands - strong molecular bands (TiO ...)(TiO ...)
- broad lines (vmacrobroad lines (vmacro10 10 km/s, Josselin et Plez km/s, Josselin et Plez 2004)2004)
continuum poorly continuum poorly defined, spectrum defined, spectrum synthesis is difficult ... synthesis is difficult ...
TimeVis
mag
Flu
x (a
rbit
rary
un
its)
AAVSO
66
RSG stars - 3RSG stars - 3
Profiles are variable in depth, width and velocity !
(stronger variations are seen in other RSG).
Time-variable structure in line profiles is a natural and necessary consequence of giant convective cells
Josselin & Plez, 2007
77
RSG stars - 4RSG stars - 4
Young et al. 2000
Bright spot model for 700 nm (TiO)
mas
mas
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Haubois et al. 2006H band - IONIC
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Alpha Ori is big and relatively nearby. Excellent target for Interferometry
Surface inhomogeneitiesSurface inhomogeneities Parametric models not enough to Parametric models not enough to
explain physicsexplain physics Need for more complicated Need for more complicated
models?models?
HST - Faint Object CameraUV
88
And the answers to RSG And the answers to RSG questions?questions?
COCO55BOLD (COnservative COde for the COmputation of BOLD (COnservative COde for the COmputation of COmpressible COnvection in a BOx of L Dimensions, COmpressible COnvection in a BOx of L Dimensions, l=2,3) developed by Freytag, Steffen, Ludwig et al. (l=2,3) developed by Freytag, Steffen, Ludwig et al. ( for for RSG, RSG, Freytag et al., 2002; 2008 in prep.))
Key point: coupling of radiation and hydrodynamics, Key point: coupling of radiation and hydrodynamics, which dominates in the physics of the transition layerswhich dominates in the physics of the transition layers
This tool will help to investigate:This tool will help to investigate:1.1. the nature of the convection patternthe nature of the convection pattern2.2. the atmospheric velocity fieldsthe atmospheric velocity fields3.3. the impact of convection on spectral lines, visibility the impact of convection on spectral lines, visibility
curves and phasescurves and phases
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OutlineOutline
RSG starsRSG stars The modeller's point of view The modeller's point of view The virtual observer’s point of viewThe virtual observer’s point of view SpectroscopySpectroscopy InterferometryInterferometry Conclusions et perspectivesConclusions et perspectives
1010
The modeller's point of view, The modeller's point of view, COCO55BOLDBOLD - 1 - 1
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STAR-IN-A-BOX setup:
• Used to model RSG stars
• The gravitation is spherical potential
• The computational domain is a cube with equidistant directions, all the 6 surfaces have the same open boundaries
• Strictly LTE and short characteristic method
• Grey and non-grey (5 bins, under development)
Bolometric Intensity - Freytag et al. 2002
1111
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http://www.astro.uu.se/~bf/ (B. Freytag)
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Velocity fieldsVelocity fields Velocities are a Velocities are a
consequence of the strong consequence of the strong convective motions.convective motions.
Shock peak velocities Shock peak velocities saturates at saturates at 25 km/s. 25 km/s.
In the upper In the upper photosphere the photosphere the velocities are typically velocities are typically supersonic (supersonic (Mach>1Mach>1).).
Approx radius position
1
Radius (Rsun)
Ma
ch
nu
mb
er
1313
RSG simulations: state-of-the artRSG simulations: state-of-the art
CPU-time: 100 days more or less continuously CPU-time: 100 days more or less continuously on CPU-clock speed of 3 GHzon CPU-clock speed of 3 GHz
Drifting parameters, but relaxation in the last partDrifting parameters, but relaxation in the last part
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Polynomial fit
Rad
ius
(Rsu
n)
Time (years)
1414
Out lineOut line
RSG starsRSG stars The modeller's point of view The modeller's point of view The virtual observer’s point of viewThe virtual observer’s point of view SpectroscopySpectroscopy InterferometryInterferometry Conclusions et perspectivesConclusions et perspectives
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3D radiative transfer code 3D radiative transfer code OPTIM3D - 1OPTIM3D - 1
Integral computed Integral computed with Gauss-Laguerre with Gauss-Laguerre quadrature of order 9 quadrature of order 9
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1.1 sec /
(numerical resolution 2353)
R = / = c/v 100000
at 6000 Å
~ 5 h / 1000Å ! (clock speed of 3 GHz)
1616
3D radiative transfer code 3D radiative transfer code OPTIM3D - 2OPTIM3D - 2
Opacity tables generated Opacity tables generated with MARCS with billion of with MARCS with billion of molecular (see Gustafsson, molecular (see Gustafsson, 2008) and atomic (VALD) 2008) and atomic (VALD) lineslines
Double linear interpolation Double linear interpolation for T and for T and only once only once
Linear interpolation at right Linear interpolation at right wavelengthwavelength
//= R = 500000= R = 500000
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3D radiative transfer code 3D radiative transfer code OPTIM3D - 3OPTIM3D - 3
Cross-check: Linfor3D on 3D Cross-check: Linfor3D on 3D CO5BOLD local model for 3 CO5BOLD local model for 3 artificial iron linesartificial iron lines
Interpolation in the opacity tables Interpolation in the opacity tables is the main cause of the differenceis the main cause of the difference
OPTIM3D OPTIM3D large range of large range of wavelength + millions of lines wavelength + millions of lines simultaneouslysimultaneously
Linfor3D Linfor3D high performing high performing abundances determinationabundances determination
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OPTIM3D produces:OPTIM3D produces:UVES lpha Ori
RHD model
To constrain the To constrain the atmospheric atmospheric dynamics dynamics
To constrain the To constrain the structure sizestructure size
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Surface pattern of RSGsSurface pattern of RSGs
2020
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H band - Large convective cellsH band - Large convective cells
Large cellLarge cell 400- 400-500 R500 Rsunsun, , lifetime lifetime of of yearsyears (st35gm03n07)(st35gm03n07)
Lifetime Lifetime intergranular intergranular lanes and dark lanes and dark spots spots few few monthsmonths
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Optical - complex convection Optical - complex convection patternpattern
Shocks+1000-1000 Rsun
H band TiO 6100 A Ca II H line
Complex substructures - More spectacular than in H band!Complex substructures - More spectacular than in H band! Inversion of the contrastInversion of the contrast Shocks in Ca II H line!Shocks in Ca II H line!
Young et al. 2000
Bright spot model for 700 nm (TiO)
mas
mas
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Star at 174.3 pc
( 44.6 mas)
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PhotocenterPhotocenter
TiO displacement up to 120 RTiO displacement up to 120 Rsunsun (15% stellar radius) and 20 R (15% stellar radius) and 20 Rsunsun for H band for H band If alpha Ori at 200pc: - TiO displacement If alpha Ori at 200pc: - TiO displacement 2.8 mas 2.8 mas ((detectable detectable
with GAIA!with GAIA!)) - H band - H band 0.5 mas 0.5 mas
H band (3.5 years covered) TiO 6100 A (1.5 years covered)
+1 mas
-1 mas
-2 mas +1 mas
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SummarySummary
The convection pattern of RSGs The convection pattern of RSGs changes with the wavelengthchanges with the wavelength
Large convective cellsLarge convective cells Spectacular in the opticalSpectacular in the optical Calibration for GAIACalibration for GAIA
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Out lineOut line
RSG starsRSG stars The modeller's point of view The modeller's point of view The virtual observer’s point of viewThe virtual observer’s point of view SpectroscopySpectroscopy InterferometryInterferometry Conclusions et perspectivesConclusions et perspectives
2525
Characteristic velocities in the atmosphere - 1Characteristic velocities in the atmosphere - 1
How to extract dynamical information ?
Tomography (Alvarez et al. 2001)
Synthetic spectrum’s CCF in the optical range
Observed CCF of MuCep (Josselin & Plez, 2007)
asymmetric, variable cross-
correlation functions (CCF)
and irregular variations
Velocity (km/s)
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Velocity (km/s)
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Characteristic velocities in the atmosphere - 2Characteristic velocities in the atmosphere - 2
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< v(C1) > = 2.3 km/s
simulation observations
The velocity amplitude is in qualitative agreement with the observations.
Even mask C1 is not 0 km/s
V466 Cas
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Characteristic velocities in the atmosphere - 3Characteristic velocities in the atmosphere - 3
Representative Observations: time covered ≈ 1.5 year (Josselin & Plez
2007)
Simulation: time covered ≈ 1.5 year
The trend of the variations is in qualitative agreement (e.g., slope of the black curve)
Velocity amplitudes larger in the observations
v(C8r) vs v(C8b)v(C8r) vs C1v(C8b) vs C1
20 km/s
8 km/s
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Characteristic velocities in the atmosphere - 4Characteristic velocities in the atmosphere - 4
Simulation: time covered ≈ 1.5 year
The trend of the variations is in qualitative agreement (e.g. slope blue and red)
C1 is deeper in the simulations
depth(C8r) vs v(C8b)
depth(C8r) vs C1
depth(C8b) vs C1
Representative Observations: time covered ≈ 1.5 year (Josselin & Plez
2007)
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CO lines comparison to Wallace & Hinkle, 1996 CO lines comparison to Wallace & Hinkle, 1996
=23057.543Å, =5.411 eV, log(gf)=-4.311
=23097.094Å, =1.476 eV, log(gf)=-4.195
< v correction > = - 2.3 km/s < v correction > = - 0.9 km/s
observations Colors 3.5 years covered
Depth and width reproduced without need for micro- or macro-turbulence.
Velocity (km/s)Velocity (km/s)
Flu
x (
arb
itra
ry u
nit
s)
Flu
x (
arb
itra
ry u
nit
s)
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CO lines comparison to Wallace & Hinkle, 1996CO lines comparison to Wallace & Hinkle, 1996
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=23057.543Å, =5.411 eV, log(gf)=-4.311
=23097.094Å, =1.476 eV, log(gf)=-4.195
Velocity (km/s)
observations
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Velocity (km/s)
Flu
x (
arb
itra
ry u
nit
s)
Flu
x (
arb
itra
ry u
nit
s)
Line asymmetries and shifts of few km/s.RHD simulation good for high but no good for lower
Colors 3.5 years covered
3131
Ti I line at 6261.11 Å - 1Ti I line at 6261.11 Å - 1
6262
Simulation - period covered 550 days with a time-step of 23 days
=6261.11Å, =3.430 eV, log(gf)=-5.735
Variations in the positions of the lines and their depths in Gray (2008), as already pointed out by Josselin & Plez 2007!!!!!!, and in RHD simulation
Variations in velocity!
a Ori (Gray, 2008)
FW
HM
(km
/s)
3232
Ti I line at 6261.11 Å - 2Ti I line at 6261.11 Å - 2 shapes at 1km/s level shifts much larger than
shape variations The predominant shape
is a reversed ”C”
Ori (Gray, 2008)
Time covered = 1.5 yQuickTime™ e un
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Velocity (km/s)
3333
SummarySummary
RHD simulations are in RHD simulations are in qualitative qualitative agreement on the velocity amplitudeagreement on the velocity amplitude with with respect to the observationsrespect to the observations
No need for macro- turbulenceNo need for macro- turbulence Velocity correction due to the convectionVelocity correction due to the convection Bisector predominant shape is a reversed Bisector predominant shape is a reversed
”C” in accord with the observations”C” in accord with the observations
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Out lineOut line
RSG starsRSG stars The modeller's point of view The modeller's point of view The virtual observer’s point of viewThe virtual observer’s point of view SpectroscopySpectroscopy InterferometryInterferometry Conclusions et perspectivesConclusions et perspectives
3535
InterferometryInterferometryIONIC filter FLUOR filters
WaterCOCN
Global spectrum
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Intensity profiles and limb-darkening - 1Intensity profiles and limb-darkening - 1
Angular intensity dispersion is larger than the temporal ones
Angular
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p/R
Temporal
Median
3737
Intensity profiles and limb-darkening - 2Intensity profiles and limb-darkening - 2
Claret LD law (2000) with new coefficients (blue)
Modification of LD law by Ludwig & Beckers (2008) (red)
Claret LD law withATLAS9 3500K,log(g)=0,
solar metallicity(green)
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p/R cycles/R
RHD snapshot
3838
Numerical resolution and Numerical resolution and visibility mapsvisibility maps
Small bright artificial Small bright artificial patches (few pixels patches (few pixels wide)wide)
Median smoothing Median smoothing appliedapplied
Difference at 7th lobe Difference at 7th lobe (0.035 R(0.035 Rsunsun
-1-1, i.e. 28 , i.e. 28
RsunRsun3.3 pixel)3.3 pixel)
cycles/Rsun
No smoothingsmoothing
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Visibility - the first lobeVisibility - the first lobe
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Angular synthetic vis H band LD UD of 16mas at 173 pc (70 Rsun)
Temporal fluctuationsAngular fluctuations
DispersionDispersion due to large (250-500 R due to large (250-500 Rsunsun) convective cells) convective cells Fluctuations are 10% at 0.006 RFluctuations are 10% at 0.006 Rsunsun
-1 -1 (first null point) (first null point) additional additional uncertainty for radius measurement!uncertainty for radius measurement!
No clear distinction between angular and temporal fluctuationsNo clear distinction between angular and temporal fluctuations
10% atfirst null
cycles/Rsun cycles/Rsun
€
Fluct =σ
vis
4040
Visibility - the second, third and fourth Visibility - the second, third and fourth lobeslobes
Clear Clear deviationdeviation from from circular symmetry. Signal circular symmetry. Signal higherhigher than UD or LD than UD or LD predictions!!!predictions!!!
Scatter becomes larger Scatter becomes larger with spatial frequencieswith spatial frequencies
Signature of the Signature of the characteristic sizecharacteristic size of of convective cellsconvective cells
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120 Rsun (15% R)
70 Rsun (8% R)
50 Rsun (6% R)
cycles/Rsun
H band LD UD of 16 mas at 173 pc (70 Rsun)
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Visibility - the second, third and fourth Visibility - the second, third and fourth lobeslobes
Temporal fluctuationsAngular fluctuations
10%
Vis<10-14% Vis<6-10% Vis<2-7%
How to detectHow to detect this with today this with today interferometer:interferometer:
1.1. Searching for angular Searching for angular fluctuations using Earth fluctuations using Earth rotation (1 night, same rotation (1 night, same configuration)configuration)
2.2. Looking for temporal Looking for temporal fluctuations (1 night, same fluctuations (1 night, same configuration at two epochs)configuration at two epochs)
4242
Comparison to observations:Comparison to observations: Ori (Haubois et al. 2006) in IONIC Ori (Haubois et al. 2006) in IONIC
First data at high First data at high spatial frequencyspatial frequency
DataData from lower to from lower to higher frequency higher frequency explainedexplained with one with one model!model!
Characterization of Characterization of the convection size. the convection size. Ori covered by cells Ori covered by cells of 50-120 Rsunof 50-120 Rsun
More measure at 20-More measure at 20-25 arcsec25 arcsec-1-1 for for signature of large cellsignature of large cell
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Spatial frequency
Sq
uar
ed V
isi b
ilit y
44.6 mas at 174.3 pc
UD of 43.65 mas
4343
Comparison to observations:Comparison to observations: Ori (Perrin et al. 2004) in K222 Ori (Perrin et al. 2004) in K222
Confirmation in Confirmation in the K band: the K band: presence of presence of cells cells of 50 to 120 Rof 50 to 120 Rsunsun
Measure at 20 to Measure at 20 to 23 arcsec23 arcsec-1-1 explainedexplained cells cells of of 200 R200 Rsunsun
UD of 43.65 mas
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Vis
ibili
ty
Spatial frequency
43.6 mas at 179 pc
UD of 43.65 masLinear LD of 43.64 mas
4444
Importance of high spectral resolution - 1Importance of high spectral resolution - 1
Variation of the interferometric data between different spectral features, and between features and continuum
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Chiavassa et al., 2007 (SF2A)
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Importance of high spectral resolution - 2Importance of high spectral resolution - 2
The visibility is The visibility is wavelength wavelength dependent!dependent!
It is It is crucialcrucial to have to have high spectral high spectral resolutionresolution
H band is a good H band is a good target target
AMBER spectral resolution of 1500
Resolution of 12000
wavelength
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45 mas at 173.5 pc
4646
Comparison to observations:Comparison to observations:Mu Cep (Perrin et al. 2005) in K band Mu Cep (Perrin et al. 2005) in K band
RHD model RHD model cannot fit all cannot fit all the data with the data with one model!one model!
Not even Not even changing changing cells cells distribution distribution
K203 K215
K222 K239
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15.8 mas at 490 pc
<2%
Spatial frequency
4747
Closure phasesClosure phases
Commonly non zero Commonly non zero or ±or ± surface surface inhomogeneitiesinhomogeneities
Wavelength Wavelength dependentdependent
Necessary to observe Necessary to observe at at high spatial high spatial frequenciesfrequencies
H band has larger H band has larger dispersion dispersion
Max baseline (m)
Clo
sure
Ph
ase
(d
eg
ree)
IONIC
K222
Structures of50 Rsun
Structures of80 Rsun
4848
SummarySummary
Average limb-darkening profileAverage limb-darkening profile Convection-related surface structures cause Convection-related surface structures cause
visibility fluctuations that:visibility fluctuations that:1.1. Add uncertainty on radius measurementAdd uncertainty on radius measurement2.2. Clearly deviate from circular symmetry at high Clearly deviate from circular symmetry at high
frequencyfrequency Ori is covered by cells of 50-120 ROri is covered by cells of 50-120 Rsunsun Importance of high spectral resolution to Importance of high spectral resolution to
characterize the convection patterncharacterize the convection pattern
4949
Out lineOut line
RSG starsRSG stars The modeller's point of view The modeller's point of view The virtual observer’s point of viewThe virtual observer’s point of view SpectroscopySpectroscopy InterferometryInterferometry Conclusions et perspectivesConclusions et perspectives
5050
Conclusions - 1Conclusions - 1 The convection pattern in RSGs is wavelength The convection pattern in RSGs is wavelength
dependent. dependent. Few largeFew large (400-500 R (400-500 Rsunsun) convective ) convective cellscells in in the IR with a lifetime of years and complex pattern in the IR with a lifetime of years and complex pattern in the optical.the optical.
RHD simulations have been compared to observations:RHD simulations have been compared to observations:n Qualitative Qualitative agreementagreement on the velocity amplitude on the velocity amplituden No needNo need for macro-turbulence for macro-turbulencen Reverse-”C” shapeReverse-”C” shape, line shifts and asymmetries without , line shifts and asymmetries without
using or macro-turbulenceusing or macro-turbulencen DetectionDetection of convection cells on of convection cells on Ori from Ori from
interferometric datainterferometric data
5151
Conclusions and predictions - 2Conclusions and predictions - 2 The predictions of the The predictions of the photocenterphotocenter
displacementdisplacement are of extreme interest for are of extreme interest for future mission like GAIAfuture mission like GAIA
Today Today interferometersinterferometers are the are the best way to best way to detectdetect and characterize the convection on and characterize the convection on RSGs. The observation must go at higher RSGs. The observation must go at higher arcsecarcsec-1-1 beyond the determination of the beyond the determination of the radius and LD. Future resolved image will radius and LD. Future resolved image will constrain RHD simulationsconstrain RHD simulations
5252
Principal problem of RHD simulation is the grey Principal problem of RHD simulation is the grey treatment of opacities. Major efforts, both human treatment of opacities. Major efforts, both human and computer must be done.and computer must be done.
Possible effects of non-grey:Possible effects of non-grey:- for spectroscopy an increase of the contrast for spectroscopy an increase of the contrast
between weak and strong lines between weak and strong lines - for interferometry a reduction of the intensity for interferometry a reduction of the intensity
map contrast that implies smaller visibility map contrast that implies smaller visibility fluctuationsfluctuations
Conclusions - 3Conclusions - 3
5353
PerspectivesPerspectives SED (e.g. effective temperature scale to compare with SED (e.g. effective temperature scale to compare with
determinations with 1D models) determinations with 1D models) Opacity SamplingOpacity Sampling in in OPTIM3D using MARCS tablesOPTIM3D using MARCS tables
Switch to Switch to non-greynon-grey (coll. With B. Freytag and H.G. Ludwig) (coll. With B. Freytag and H.G. Ludwig) Inclusion of Inclusion of radiation pressureradiation pressure to study the winds (coll. to study the winds (coll.
with B. Freytag)with B. Freytag) More models of RSGs with different fundamental More models of RSGs with different fundamental
parameter neededparameter needed Natural extension of the work to Natural extension of the work to AGB and RGBAGB and RGB stars (e.g., stars (e.g.,
1D models by S. Höfner or 3D by B. Freytag and 3D local 1D models by S. Höfner or 3D by B. Freytag and 3D local models by H.G. Ludwig)models by H.G. Ludwig)
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Merci - GrazieMerci - Grazie!!!!!!
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5656
RSG stars - 2RSG stars - 2
The The relevant scalerelevant scale of convection is still uncertain of convection is still uncertain (large convective cells? Schwarzschild, 1975)(large convective cells? Schwarzschild, 1975)
The interpretation of the fundamental The interpretation of the fundamental parameters is based on a correct parameters is based on a correct characterizationcharacterization ofof RSG RSG convectionconvection
Strong Strong mass-lossmass-loss of unknown origin. Convection of unknown origin. Convection can explain?can explain?
The existence of The existence of MOLsphereMOLsphere around RSG is around RSG is sitll an open questionsitll an open question
5757
Velocity fieldsVelocity fields Velocities are a Velocities are a
consequence of the strong consequence of the strong convective motions.convective motions.
Radius (Rsun)
Radius (Rsun)
Ve
loc
ity
(km
/s)
+ 30
- 30
Shock peak velocities Shock peak velocities saturates at saturates at 25 km/s. 25 km/s.
In the upper In the upper photosphere the photosphere the velocities are typically velocities are typically supersonic (supersonic (Mach>1Mach>1).).
--- Approx radius position Sound speed
Approx radius position
Ma
ch
nu
mb
er
1
5858
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Comparison to water vapor lines at 12 Comparison to water vapor lines at 12 m by m by Ryde et al. 2006Ryde et al. 2006
3D simulation1D MARCS at 3600K1D MARCS at 3200K
Observations
RHD simulation reproduce RHD simulation reproduce well Hwell H22O but there is no O but there is no
way to explain OH lines, way to explain OH lines, even changing the O even changing the O abundanceabundance
Shallow 3D temperature Shallow 3D temperature gradient. gradient.
Work still in progress, Work still in progress, testing MOLsphere testing MOLsphere modelsmodels
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H2O
OH
MARCS 3200KMARCS 3600K
<3D>QuickTime™ e un
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5959
Granulation contrastGranulation contrast
Under or over-estimated granulation size Under or over-estimated granulation size contrast in RHD models?contrast in RHD models?
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In the intensity contrast is 50% smaller, the visibility fluctuations are also 50% (second and third lobe) and 40% (fourth lobe) smaller.
More difficult to detect!!!
Solid : top second lobeDotted : top third lobe
Dashed : top fourth lobe
6060
Comparison to observations:Comparison to observations:Mu Cep (Perrin et al. 2005) in K band - 2Mu Cep (Perrin et al. 2005) in K band - 2
MOLsphere extensionMOLsphere extension model with 7.91 mas, model with 7.91 mas, T=1700,T=1700,=10=10-12 -12 gr/cmgr/cm33
OK K203, unable to OK K203, unable to explain K239!explain K239!
Too high Too high or T or T opaque. opaque. Observational Observational check?check?
In progress, checking In progress, checking spectra Kband + 12 spectra Kband + 12 m m
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Spatial frequency
K203 K239
6161
Importance of high spectral resolution - 2Importance of high spectral resolution - 2AMBER resolution of AMBER resolution of 3535
1.6 m-[0,310000] 2.22 m -[0,150000] 2.33 m -[0,90000]
H band contrast between dark and bright regions > K 2.22
Visibility is wavelength dependent
H band continuum is more interesting
But difficult to see difference from fluctuations at this resolution
cycles/Rsuncycles/Rsun
6262
Visibility in TiO Visibility in TiO bandsbands
QuickTime™ e undecompressore TIFF (LZW)
sono necessari per visualizzare quest'immagine.
QuickTime™ e undecompressore TIFF (LZW)
sono necessari per visualizzare quest'immagine.