The MESA Stellar Evolution Code - UW Madison …townsend/resource/talks/uw-mesa.pdfThe MESA Stellar...

University of Wisconsin-Madison

Topics in Computing for Astronomy — Oct 30 2012

Rich Townsend

log Density (g cm�3)

log

Tem

pera

ture

(K)

OPAL

SCVH

PC

HELM

HELM

e�e+

oxygen� =

175

0.001M�

0.8M� WD1.0M�25M�

�10 �8 �6 �4 �2 0 2 4 6 82

3

4

5

6

7

8

9

10

The MESA Stellar Evolution Code

Tuesday, October 30, 12

Modules for Experiments in Stellar Astrophysics


Why a New Stellar Evolution Code?• Openness: anyone can download sources from the website.

• Modularity: independent modules for physics and for numerical algorithms; the parts can be used stand-alone.

• Comprehensive Microphysics: up-to-date, wide-ranging, flexible, and independently useable microphysics modules.

• Modern Techniques: advanced AMR, fully coupled solution for composition and abundances, mass loss and gain, etc.

• Performance: runs well on a personal computer and makes effective use of parallelism with multi-core architectures.

• Wide Applicability: capable of calculating the evolution of stars in a wide range of environments.


The MESA Council

• Members:• Lars Bildsten (UCSB/KITP)• Bill Paxton (UCSB/KITP)• Frank Timmes (Arizona State)• Falk Herwig (University of British Columbia)• Ed Brown (Michigan State)• Aaron Dotter (STScI; now Oz)• Matteo Cantiello (UCSB/KITP)• Rich Townsend (University of Wisconsin-Madison)

• Duties• Code development• Instrument paper(s)• Infrastructure maintenance (website, forum, SDK)• Summer schools


Online MESA Resources• Website (main resource):

• Mailing list (bug reports, results):

• Forum (bug reports, results, lectures, FAQs):

• SDK (software tools):

• Instrument paper:

https://lists.sourceforge.net/lists/listinfo/MESA-users

http://mesa.sourceforge.net/index.html

http://mesastar.org/

http://www.astro.wisc.edu/~townsend/static.php?ref=mesasdk

http://adsabs.harvard.edu/abs/2011ApJS..192....3P






http://mesastar.org

http://mesastar.org





●

●

●

●

●

●

●●

●

ZAMS

log T

e↵ (K)

lo

gL/L�

0.9

Y = 0.28

Z = 0.02

1.2

1.5

2.0

3.53.63.73.83.9

0

12

3

4

✏F/kT=4

✏F/kT=20

log P=20.25

log ⇢c

(g cm

�3

)

lo

gT

c(K

)

0.91.2

1.52.0

1 2 3 4 5 6

7.0

7.5

8.0

MESA in Action: Low-Mass Stellar Evolution

• Code goes through He core flash without problems

• No need for ad-hoc ‘transition’ between RGB and HB (i.e., no EZ-Web fudge)

• Thermal pulses on AGB also handled

• Mass-loss allows evolution through to WD remnant

From MESA Instrument PaperTuesday, October 30, 12

MESA in Action: Intermediate-Mass Stars

log T

e↵

log

L/L�

3.423.443.463.483.503.523.543.56

3.4

3.6

3.8

4.0

✏F/kT=30

log ⇢c

(g cm

�3

)

log

T

c

(K

)

6.1 6.2 6.3 6.4

7.8

6

7.8

97.9

2

7.9

5

● ●

●

●

●

●

●●

●

●●●●●

●●●

ZAMS

log T

e↵ (K)

lo

gL

(L

�)

2

3

4

5

6

7

8

10

3.63.84.04.24.4

12

3

4

✏F/kT=4

Y = 0.28

Z = 0.02

log ⇢c

(g cm

�3

)

lo

gT

c(K

)

2

2

3

3

4

4

5

5

6

6

7

7

8

8

10

10

0 1 2 3 4 5 6 7

7.0

7.5

8.0

8.5

9.0


MESA in Action: Massive Stars to Core Collapse

Tc / ⇢1/3c

MESAKEPLERHMMLC06

Mi = 25M�Zi = 0.02

He burn

C burn

Ne burn

O burn

Si burn

log ⇢c (g cm�3)

log

T c(K

)

3 4 5 6 7 8 9

8.5

9.0

9.5

10.0

m (M�)

log

mas

sfr

actio

n

4He 4He

4He

4He

4He

12C

16O

16O16O

20Ne

20Ne

24Mg

24Mg

28Si

28Si28Si

28Si

28Si

28Si

32S

32S32S

32S

32S

36Ar36Ar

36Ar

40Ca40Ca

40Ca

54Fe54Fe

54Fe

54Fe54Fe

56Fe56Fe 56Fe

56Fe 56Fe

56Fe 56Fe

56Ni56Ni

“56Cr”“56Cr”

“56Cr”

“56Cr”

“56Cr”

neutneut

M0 = 25M�Z0 = 0.02

0.5 1.0 1.5 2.0 2.5

�3�2

�10


MESA in Action: Brown Dwarfs & Giant Planets

■●▲

■

●

▲

■

●

▲

■

●

▲

■

●

▲

■

●

▲

■

●

▲

■

●

■

●

■

●

■

●

■

●

■■■■■ ■ ■

■■

■

✏F

/kT=4

T

c

/ ⇢1/3c

10

30

100

300

1000

D Depletion

7

Li Depletion

ZAMS

Y = 0.275

Z = 0.019

log ⇢c

(g cm

�3

)

log

T

c

(K

)

0.3

0.2

0.15

0.12

0.1

0.09

0.08

0.075

0.07

0.065

0.06

0.055

0.05

0.045

0.04

0.035

0.03

0.025

0.02

0.017

0.014

0.012

0.011

0.01

0

1 2

3

5.5

6.0

6.5

7.0


MESA in Action: Evolution of a Solar-Mass Star

Credit: Josiah Schwab


MESA in Action: Evolution of a Solar-Mass Star

Credit: Josiah Schwab


Installing MESA

• Obtain a current copy of the MESA tree:

• Set environment variables:

• Build MESA:

• Caveats:• Revision number is always changing; see http://mesa.sourceforge.net/getting_started.html• Takes up 4GB of disk space or more• Change OMP_NUM_THREADS to number of processor cores on your machine• Change syntax of environment-variable setting if you are using csh

svn co -r 4631 http://mesa.svn.sourceforge.net/svnroot/mesa/trunk mesa-4631

export OMP_NUM_THREADS=8export MESA_DIR=<blah>/mesa-4298

cd $MESA_DIR./install


http://mesa.sourceforge.net/getting_started.html

http://mesa.sourceforge.net/getting_started.html

http://mesa.svn.sourceforge.net/svnroot/mesa/trunk

http://mesa.svn.sourceforge.net/svnroot/mesa/trunk

The MESA Software Development Kit (SDK)

• What’s it for?• Hassle-free compilation of MESA• Works on Linux and Mac OS X (Intel-based)

• What’s in it?• gcc/gfortran 4.7 compilers (good support for Fortran 2003)• BLAS/LAPACK libraries (linear algebra)• PGPLOT library (graphics)• HDF5 library (file storage)

• Where do I get it from?

• How do I install?• Linux: unpack tar archive (anywhere; don’t need to be root user)• OS X: drag package into Applications folder





Running an Example: Solar-Mass Evolution

• Change into the example directory:

• Build the code:

• Run the code:

• Output produced in LOGS subdirectory:• history.data — global properties of all models in run• profileN.data (N=1,2,…) — internal structure of selected models• profiles.index — mapping between model number and N

cd $MESA_ROOT/star/test_suite/1M_pre_ms_to_wd/

./mk

./rn


Modifying the Example: Enabling Plotting

• Edit the inlist_1.0 file:

• Run the code:

!pgstar_flag = .true.

pgstar_flag = .true.

./rn


Understanding inlist Files• inlist format is defined by Fortran standard

• Overall file structure:

&star_job …/ ! end of star_job namelist

&controls …/ ! end of controls namelist

&pgstar …/ ! end of pgstar namelist

Overall run parameters

Detailed control parameters

Plot parameters


Understanding inlist Files (cont.)&star_job

mesa_dir = '../../..'

read_extra_star_job_inlist1 = .true. extra_star_job_inlist1_name = 'inlist_sub'

/ ! end of star_job namelist

&controls initial_mass = 1.0 initial_z = 0.02d0

/ ! end of controls namelist

…

Path to $MESA_DIR dir

Read subsidiary inlist

Mass & metallicity


• Grab the read_mesa.pro IDL procedure :

• Read data into IDL structures:

Reading MESA Output Files

IDL> s = read_mesa(‘profile1.data’)IDL> help, s, /strIDL> plot, s.logrho, s.logT

http://mesastar.org/tools-utilities/idl

IDL> s = read_mesa(‘history.data’)IDL> help, s, /strIDL> plot, s.log_Teff, s.log_L, xrange=[4.5,3.5], yrange=[0,4]




Other test_suite Examples

• sample_zams — build multiple ZAMS models

• 7M_prems_to_AGB – 7 M☉, pre-main sequence to AGB

• example_astero — asteroseismology using adipls code (supplied)

• binary_rlo — Roche-lobe overflow in binary system

• 1.5M_with_diffusion – 1.5 M☉, elemental diffusion

• massive_rotating – 15 M☉, initial rotation at 50% critical

• ns_c – 1 M☉ neutron star, accreting/burning carbon


Rolling Your Own• Copy one of the test_suite directories:

• Delete the MESA_DIR definition from my_project/make/makefile (this will cause MESA to pick up the definition from the MESA_DIR environment variable)

• Delete the mesa_dir definition from the inlist (this will cause MESA to pick up the definition from the MESA_DIR environment variable)

• Edit the inlist(s)• Edit source files in my_project/src• Clean, make and run:

cp -a $MESA_DIR/star/test_suite/1M_pre_ms_to_wd my_project

cd my_project; ./clean; ./mk; ./rn


Date post:	27-Mar-2018
Category:	Documents
Upload:	dangdieu
View:	219 times
Download:	1 times

The MESA Stellar Evolution Code - UW Madison …townsend/resource/talks/uw-mesa.pdfThe MESA Stellar...

Documents