Package enrichpy :: Module lifetime

Module lifetime

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Stellar lifetimes as a function of stellar mass, and related functions.

Functions

main_sequence_life(mass)
Rough approxiamtion of main sequence lifetime in years.

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mass_from_main_sequence_life(life)
Approximate mass given main sequence lifetime in years.

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invert_function(function, xmin, xmax, xstep, bounds_error=False)
Invert function y = F(x) using interpolation.

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invert_function_log(function, logxmin, logxmax, logxstep, bounds_error=False)
Invert function y = F(x) using interpolation.

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invert_function_semilogy(function, xmin, xmax, xstep, bounds_error=False)
Invert function y = F(x) using interpolation.

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mass_from_main_sequence_life_function(function, mmin=0.0, mmax=1000.0, mstep=0.01)
Returns a function giving stellar mass from lifetime.

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main_sequence_life_MM89(mass)
Lifetime in years from Maeder & Meynet (1989) via Romano et al. (2005).

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main_sequence_life_K97(mass)
Lifetime in years from Kodama (1997) via Romano et al. (2005).

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test_conversion(lifetime_function)
Tests conversion of mass into lifetime and back. Note that this test is not passed right now because of the numerical discontinuties in the lifetime functions where their different segments meet up.

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Variables
	__package__ = `'enrichpy'`

Function Details

main_sequence_life(mass)

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Rough approxiamtion of main sequence lifetime in years.

tauMS ~ 10^10 years * (M/Msun)^-2.5

mass in solar masses.

mass_from_main_sequence_life(life)

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Approximate mass given main sequence lifetime in years.

tauMS ~ 10^10 years * (M/Msun)^-2.5

mass in solar masses.

invert_function(function, xmin, xmax, xstep, bounds_error=False)

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Invert function y = F(x) using interpolation.

Returns an interpolation function giving x as a function of y.

invert_function_log(function, logxmin, logxmax, logxstep, bounds_error=False)

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Invert function y = F(x) using interpolation.

Internally uses logarithmic scale in the x values and in performing the interpolation.

Returns

an interpolation function giving x as a function of y. NOTE: provide y, don't provide log(y).

invert_function_semilogy(function, xmin, xmax, xstep, bounds_error=False)

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Invert function y = F(x) using interpolation.

Internally uses logarithmic scale in the y values.

Returns

an interpolation function giving x as a function of y. NOTE: provide y, don't provide log(y).

mass_from_main_sequence_life_function(function, mmin=0.0, mmax=1000.0, mstep=0.01)

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Returns a function giving stellar mass from lifetime.

Uses invert_function_semilogy to define an interpolation function that will return stellar mass when given stellar lifetime.

main_sequence_life_MM89(mass)

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Lifetime in years from Maeder & Meynet (1989) via Romano et al. (2005).

The minlife attribute gives the minimum lifetime for a star as M->inf.

Parameters

mass (1D array):: Stellar mass in solar masses.

Notes

From Maeder & Meynet (1989), via Romano, Chiappini, Matteucci, Tosi, 2005, A&A, 430, 491 (2005A&A...430..491R), who say:

t =
  10^(-0.6545 logm + 1) for m <= 1.3 MSun
  10^(-3.7 logm + 1.35) for 1.3 < m/MSun <= 3
  10^(-2.51 logm + 0.77) for 3 < m/MSun <= 7
  10^(-1.78 logm + 0.17) for 7 < m/MSun <= 15
  10^(-0.86 logm - 0.94) for 15 < m/MSun <= 60
  1.2 m^-1.85  +  0.003 for m > 60 MSun
with t in units of Gyr.

main_sequence_life_K97(mass)

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Lifetime in years from Kodama (1997) via Romano et al. (2005).

The minlife attribute gives the minimum lifetime for a star as M->inf.

Parameters

mass: array: Stellar mass in solar masses.

Notes

50 for m <= 0.56 MSun 10^((0.334 - sqrt(1.790 - 0.2232*(7.764 - logm)))/0.1116) for m <= 6.6 MSun 1.2 m^-1.85 + 0.003 for m > 6.6 MSun