Multiple spiral branches on late AGB stars Qian Wang Iowa State University
Mar 27, 2015
Multiple spiral branches on late AGB stars
Qian WangIowa State University
LL pagasi (Sahai 2010)
Sahai 2006
Model method
Bowen code Passing planet
+
Bowen code
• 1-D code with Lagrange zoning.• Hydrodynamic and thermodynamic equation
without magnetic field.• Atmosphere is driven by a sinusoidal piston
below photosphere.• Density dependent thermal relaxation and
Hydrogen cooling at high temperature• Radiation on dust grain and molecules
Companion characters
• The companion is on a circular orbit. • The mass of the companion ~ 10Mjupiter• The size of the companion is determined by
the average Jupiter density.• The companion has no collision cross section
but only gravity.
Model parametersMass(Msun) 1
Luminosity(Lsun) 5000
T(K) 2966
R(Rsun) 267.8
Vterminal(km/s at 18R*) 9.35km/s
Mdot(Msun/yr) 1.25e-6
Pulsation period (day) 394
Pulsation Amp.(km/s) 3.974km/s
Model parametersModel NO. Mp(Mjupit
er)D (Rstar) Porb (days) # of spirals Tss (Ppuls)
1 2 1.01889 522.43 4 60
2 5 1.01889 522.43 4 60
3 5 1.1 586.1 3 60
4 8 1.1 586.1 3 60
5 10 1.1 586.1 3 60
6 12 1.1 586.1 3 60
7 10 1.325 775.082 2 60
8 10 1.339 786.94 2 400
9 10 12.94 23640 1 60
10 20 18.187 39400 1 100
Origin of super shocksSuper shock clustering Shock speed vs Shock Density
Shock effectsStrong shocks and Temp. contour Weak shocks and Temp. Contour
Shock effectsStrong shocks and Molecular accel. contour Strong shocks and dust accel. contour
Model analysisDensity Profile at time = 700 cycles
Extended density contour of Model 5 at time = 1200 cycles
Model 6
Model 5
Model 4
Model 3
3 spiral armsDensity color map of Model 5 Kinetic Temperature map of Model 5
R(cm)
Time (cycle)
Density color map
4 spiral armsDensity color map of Model 1 Density color map of Model 2
4 spiral armsDensity Profile at time = 700 cycles Model 1 Density Profile at time = 700 cycles Model 2
2 spiral armsDensity color map of Model 7 Density color map of Model 8
2 spiral armsDensity Profile at time = 700 cycles Model 7 Density Profile at time = 700 cycles Model 8
1 spiral armDensity color map of Model 9 Density color map of Model 10
1 spiral armDensity Profile at time = 700 cycles Model 9 Density Profile at time = 700 cycles Model 10
Equation for super shocks
€
Pss =Ppuls × Porb
Porb −N × (Porb − Ppuls)
Observation results
IRC-10216 (Mauron & Huggins 2000)
Questions and suggestions
Maybe I can explain this