vice.mlr¶
The Mass-Lifetime Relationship (MLR) for Stars: VICE provides several functional forms available for individual calculations as well as for use in chemical evolution models.
Signature: vice.mlr
New in version 1.3.0.
Contents¶
- setting
str
A string denoting which of the following functional forms is to describe the MLR in all chemical evolution models.
- recognized
tuple
A tuple of strings denoting the allowed values of the parameter
setting
. Each string corresponds directly to the name of the function to adopt.“powerlaw”
“vincenzo2016”
“hpt2000”
“ka1997”
“pm1993”
“mm1989”
“larson1974”
- powerlaw<function>
The MLR parameterized by a single power-law, a popular exercise in undergraduate astronomy courses.
- vincenzo2016<function>
The MLR as characterized by Vincenzo et al. (2016) [1].
- hpt2000<function>
The MLR as described in Hurley, Pols & Tout (2000) [2].
- ka1997<function>
The MLR as tabulated in Kodama & Arimoto (1997) [3].
- pm1993<function>
The MLR as formulated by Padovani & Matteucci (1993) [4].
- mm1989<function>
The MLR as characterized by Maeder & Meynet (1989) [5].
- larson1974<function>
The MLR as parameterized by Larson (1974) [6].
- test<function>
Run unit-tests on VICE’s MLR capabilities.
The following forms of the mass-lifetime relation take into account the metallicity dependence:
“vincenzo2016” : Vincenzo et al. (2016)
“hpt2000” : Hurley, Pols & Tout (2000)
“ka1997” : Kodama & Arimoto (1997)
The following require numerical solutions to the inverse function (i.e. stellar mass as a function of lifetime), and consequently can increase the required integration times in chemical evolution models, particularly for fine timestepping:
“hpt2000” : Hurley, Pols & Tout (2000)
“ka1997” : Koama & Arimoto (1997)
“mm1989” : Maeder & Meynet (1989)
The following quantify the total lifetimes a priori, and any prescription for the post main sequence lifetimes will consequently be neglected in chemical evolution models:
“vincenzo2016”: Vincenzo et al. (2016)
“ka1997” : Kodama & Arimoto (1997)
Except where measurements of the total lifetimes are available, VICE always
implements the simplest assumption of allowing the user to specify the
parameter postMS
describing the ratio of post main sequence to main
sequence lifetimes, and the total lifetime then follows trivially via:
where \(p_\text{MS}\) denotes this ratio.
Note
For reasons relating to the implementation, this set of functions
is not a module but an object. Consequently, importing them with
from vice import mlr
will work fine, but for example
from vice.mlr import vincenzo2016
will produce a
ModuleNotFoundError
. If necessary, new variables can always be
assigned to map to these functions (e.g.
vincenzo2016 = vice.mlr.vincenzo2016
).