Modules for Experiments in Stellar Astrophysics
MESA is a state-of-the-art,
modular, open source suite
for stellar evolution
Bill Paxton, father of MESA
 MESA Stellar Evolution Code: mesa.sourceforge.net
 MESA Instrument Papers (Paxton et al. 2011, 2013)
User Base
South
acific
Ocean
North
Atlantic
Ocean
South
Atlantic
Ocean
Indian
Ocean
MESA: ~740 Users April 2014
MESA: ~210 USA Users April 2014
MESA: ~410 Europe Users April 2014
MESA Capabilities
Capabilities
 Mass loss/gain, Schwarzschild/Ledoux, double diffusion,
gravitational settling, radiative levitation...
 It includes the physics of rotation (in a diffusion
approximation) and of dynamo generated magnetic fields in
radiative zones
 Asteroseismology : MESA is natively coupled with two
oscillations codes: ADIPLS (J. Christensen-Dalsgaard 2008)
and the non-adiabatic code GYRE (Townsend & Teitler 2013)
 Giant planets, Low-mass stars, Massive Stars, Compact
Objects, Asteroseismology, Accretion / Massloss...
(Paxton+ 2011, 2013)
 Uninterrupted evolution to WD and core-collapse
Evolution to core−collapse
M/M ≤ 100: Z=0.02 Ω /Ωcrit = 0.2
M/M ≥ 120: Z=0.001 Ω /Ωcrit = 0.2
4
10.0
Si
9.5
log Tc (K)
2
O
0
3 M!
Γ1 < 4/3
9.0
Ne
C
5 M!
7 M!
3 M! He
−2
log L/L!
Single stars with
5.5
5.0
8.5
4.5
log Teff (K)
4.0
3.5
He
2
(Paxton+ 2013)
4
6
log ρc (g cm−3)
30M
40M
50M
60M
70M
80M
90M
100M
120M
150M
250M
500M
1000M
8
10
 Mass loss/gain, Schwarzschild/Ledoux, overshooting,
double diffusion, gravitational settling, radiative levitation...
0.7
0.8
0.9
Ledoux
αsc = 0.001
αsc = 0.01
αsc = 0.02
αsc = 0.07
Schwarzschild
fov = 0.004
fov = 0.006
fov = 0.01
fov = 0.015
M = 1.5 M!
Y = 0.25, Z = 0.02
0.6
0.05
log L/L!
Ledoux
αsc = 0.001
αsc = 0.01
αsc = 0.02
αsc = 0.07
Schwarzschild
fov = 0.004
fov = 0.006
fov = 0.01
fov = 0.015
0.10
0.15
M = 1.5 M!
Y = 0.23, Z = 0.02
0.00
Mcc /M!
Single stars with
0
1
2
Age (Gyr)
3
4
3.82
3.80
3.78
3.76
log Teff
(Paxton+ 2013)
Single stars with
 Includes the physics of rotation (in a diffusion approximation)
and of dynamo generated magnetic fields in radiative zones
19
M=15
20
Rotation and B-fields
0
MESA 15MAG
50% H burned
(Paxton+ 2013)
Log j
Log
18
-2
log D [cm2/s]
log j (cm2/s)
17
16
pre-SN
O depletion
C depletion
C ignition
He depletion
He ignition
H depletion
H ignition
15
14
5
10
enclosed mass/
10
-6
5
MLT
DSI
SSI
ES
GSF
ST
13
0
-4
15
0
0
-8
-10
2
4
6
8
10
enclosed mass/M
12
14
log angular velocity (rad/s)
15
Giant Planets with
(Paxton+ 2013)
0.8
0.4
105 0.0
T
X
Y
m
L
"nuc
S1
S2
S3
N
νmax
103
102
10
ν/µHz
104
T , L, m, "nuc scaled to max
Asteroseismology with
HD49385
0.01
0.1
r/R
(Paxton+ 2013)
1
Binary Stars with
 2 stars evolved at the same time
 Implicit mass transfer (“Ritter” formalism)
 Magnetic Braking (Rappaport, Verbunt & Joss 1983)
 GW-Braking
Ready for “Testing”
 Irradiation
 Tides (Zahn 1977, Tassoul & Tassoul)
 Angular momentum accretion
 L-S coupling
Not there yet
Bill Paxton & Pablo Marchant Campos www.astro.uni-bonn.de/~pablo
[email protected]
!
Work in Progress