vice.mlr.vincenzo2016

Compute either the lifetime or the mass of a dying star according to the mass-lifetime relation of Vincenzo et al. (2016) [1].

Signature: vice.mlr.vincenzo2016(qty, Z = 0.014, which = “mass”)

New in version 1.3.0.

Parameters

qtyfloat

Either the mass of a star in \(M_\odot\) or the age of a stellar population in Gyr. Interpretion set by the keyword argument which.

Zfloat [default0.014]

The metallicity by mass of the stellar population.

whichstr [case-insensitive] [default“mass”]

The interpretation of qty: either "mass" or "age" (case-insensitive). If which == "mass", then qty represents a stellar mass in \(M_\odot\) and this function will compute a lifetime in Gyr. Otherwise, qty represents the age of a stellar population and the mass of a star with the specified lifetime will be calculated.

Returns

xfloat

If which == "mass", the lifetime of a star of that mass and metallicity in Gyr according to the Vincenzo et al. (2016) relation. If which == "age", the mass of a star in \(M_\odot\) with the specified lifetime in Gyr.

Notes

This relation is of the following functional form:

\[\tau = A \exp(B m^{-C})\]

where \(A\), \(B\), and \(C\) are functions of metallicity. Vincenzo et al. (2016) computed the values of these coefficients using the PARSEC stellar evolution code (Bressan et al. 2012 [2]; Tang et al. 2014 [3]; Chen et al. 2015 [4]) which were then used in combination with a one-zone chemical evolution model to reproduce the color-magnitude diagram of the Sculptor dwarf galaxy.

VICE stores a table of values of \(A\), \(B\), and \(C\) as internal data, interpolating linearly between them in metallicity \(Z\). This form of the mass-lifetime relation quantifies the total lifetimes of stars (i.e. the post main sequence lifetimes are included a priori, and calculating main sequence lifetimes only is not available).

Example Code

>>> import vice
>>> vice.mlr.vincenzo2016(1) # the lifetime of the sun
11.146605845086224
>>> vice.mlr.vincenzo2016(1, Z = 0.007) # at half solar metallicity
8.873217338534232
>>> vice.mlr.vincenzo2016(1, which = "age") # what mass lives 1 Gyr?
2.2090823821884733
>>> vice.mlr.vincenzo2016(2, which = "age") # 2 Gyr?
1.7081324509721378
>>> vice.mlr.vincenzo2016(2, Z = 0.007, which = "age")
1.6033524375573776
>>> vice.mlr.vincenzo2016(3)
0.48203178060452745
>>> vice.mlr.vincenzo2016(3, Z = 0.001)
0.33000930985434906
>>> vice.mlr.vincenzo2016(3, which = "age")
1.4878361243926437