Model parameter reference
All model behaviour is controlled through a single dictionary (parameters.paramsDefault). A modified parameter dictionary can be created with parameters.NewParams(**kwargs), which copies the defaults and overrides the specified keys:
import mors
my_params = mors.NewParams(dAgeMax=10.0, CoreEnvelopeDecoupling=False)
star = mors.Star(Mstar=1.0, Omega=1.0, params=my_params)
Numerical integration
| Parameter |
Default |
Description |
TimeIntegrationMethod |
'RosenbrockFixed' |
ODE solver (options: ForwardEuler, RungeKutta4, RungeKuttaFehlberg, Rosenbrock, RosenbrockFixed) |
AgeMinDefault |
\(1.0\) Myr |
Default start age of evolutionary tracks |
AgeMaxDefault |
\(5000.0\) Myr |
Default end age of evolutionary tracks |
dAgeMin |
\(10^{-5}\) Myr |
Minimum allowed timestep |
dAgeMax |
\(50.0\) Myr |
Maximum allowed timestep |
nStepMax |
\(10^6\) |
Maximum number of timesteps before error |
Physical processes
| Parameter |
Default |
Description |
CoreEnvelopeDecoupling |
True |
Enable two-zone core–envelope model |
WindTorque |
True |
Include wind spin-down torque |
CoreEnvelopeTorque |
True |
Include core–envelope coupling torque |
DiskLocking |
True |
Include disk-locking torque |
MomentInertiaChangeTorque |
True |
Include moment of inertia change torque (do not disable) |
CoreGrowthTorque |
True |
Include core-growth torque (do not disable) |
BreakupMdotIncrease |
True |
Enhance \(\dot{M}\) when approaching breakup rotation |
ExtendedTracks |
False |
Return full set of output quantities (overridden to True by Star and Cluster) |
Two-zone thresholds
| Parameter |
Default |
Description |
MstarThresholdCE |
\(0.35\,M_\odot\) |
Stars below this mass are treated as fully convective |
IcoreThresholdCE |
\(0.01\) |
Core–envelope decoupling disabled if \(I_\mathrm{core}/I_\mathrm{total}\) is below this value |
Disk locking
| Parameter |
Default |
Description |
aDiskLock |
\(13.5\) |
Coefficient \(a\) in \(t_\mathrm{disk} = a\,\Omega_0^b\) |
bDiskLock |
\(-0.5\) |
Exponent \(b\) in \(t_\mathrm{disk} = a\,\Omega_0^b\) |
ageDLmax |
\(15.0\) Myr |
Maximum disk-locking age |
Wind and magnetic field
| Parameter |
Default |
Description |
Kwind |
\(11.0\) |
Wind torque normalisation constant \(K_\tau\) |
BdipSun |
\(1.35\) G |
Solar dipole field strength \(B_{\mathrm{dip},\odot}\) |
aBdip |
\(-1.32\) |
Power-law index of \(B_\mathrm{dip}\)–\(Ro\) relation |
RoSatBdip |
\(0.0605\) |
Saturation Rossby number for \(B_\mathrm{dip}\) |
MdotSun |
\(1.4 \times 10^{-14}\,M_\odot\,\mathrm{yr}^{-1}\) |
Solar mass loss rate |
aMdot |
\(-1.7591\) |
Power-law index on \(Ro\) in \(\dot{M}\) relation |
bMdot |
\(0.6494\) |
Power-law index on \(M_\star\) in \(\dot{M}\) relation |
RoSatMdot |
\(0.0605\) |
Saturation Rossby number for \(\dot{M}\) |
fracBreakThreshold |
\(0.1\) |
Fraction of \(\Omega_\mathrm{break}\) at which magnetocentrifugal enhancement begins |
Core–envelope coupling
| Parameter |
Default |
Description |
aCoreEnvelope |
\(25.6015\) |
Coefficient \(a_\mathrm{ce}\) in coupling timescale |
bCoreEnvelope |
\(-3.4817 \times 10^{-2}\) |
Exponent \(b_\mathrm{ce}\) in coupling timescale |
cCoreEnvelope |
\(-0.4476\) |
Exponent \(c_\mathrm{ce}\) in coupling timescale |
timeCEmin |
\(0.0\) Myr |
Minimum allowed core–envelope coupling timescale |
X-ray emission
| Parameter |
Default |
Description |
RoSatXray |
\(0.0605\) |
Saturation Rossby number for X-ray emission |
RxSatXray |
\(5.135 \times 10^{-4}\) |
\(R_X\) at the saturation threshold |
beta1Xray |
\(-0.135\) |
Power-law index \(\beta_1\) in the saturated regime |
beta2Xray |
\(-1.889\) |
Power-law index \(\beta_2\) in the unsaturated regime |
sigmaXray |
\(0.359\) dex |
Standard deviation of log-normal X-ray variability scatter |
Rotation fitting
| Parameter |
Default |
Description |
Omega0FitMin |
\(0.1\,\Omega_\odot\) |
Minimum initial rotation rate considered when fitting |
Omega0FitMax |
\(50.0\,\Omega_\odot\) |
Maximum initial rotation rate considered when fitting |
nStepMaxFit |
\(1000\) |
Maximum bisection steps when fitting initial rotation |
toleranceFit |
\(10^{-5}\) |
Convergence tolerance for rotation fitting |
Other
| Parameter |
Default |
Description |
dMstarPer |
\(0.1\,M_\odot\) |
Half-width of mass bin used when computing rotation percentiles |
AgeHZ |
\(5000.0\) Myr |
Age at which habitable zone boundaries are calculated |
A modified parameter dictionary can be created with parameters.NewParams(**kwargs), which copies the defaults and overrides the specified keys.