In [1]:

    

%pylab inline
from matplotlib.pyplot import *
from numpy import *


    

    




Populating the interactive namespace from numpy and matplotlib

In [2]:

    

alpha=[1.593890e3,2.706708e3,1.466143e2,4.141960e-2,3.426349e-1]
beta=[2.053038e3,1.483131e3,-1.048442e2,4.564888e-2,0.0]
gamma=[1.231226e3,5.772723e2,-6.795374e1,2.958542e-2,0.0]
eta=[2.327785e2,7.411230e1,-1.391127e1,5.571483e-3,0.0]


    

In [7]:

    

def f_lft(mass,z):
    """ calculate MS lifetime based on mass and metallization
    Parameters
    ---------
        mass: MS mass in M_sun
        z: 0.02 as solar metallicity
    Returns
    -----
        MS lifetime in the form of mass
    """
    ksi=log10(z/0.02)
    a=lambda n: alpha[n-1]+beta[n-1]*ksi+gamma[n-1]*ksi**2+eta[n-1]*ksi**3
    T=lambda M: (a(1)+a(2)*M**4+a(3)*M**5.5+M**7)/(a(4)*M**2+a(5)*M**7)
    return map(T,mass)


    

In [8]:

    

mass=10**linspace(-0.4,2.8,33)
l1=loglog(mass,f_lft(mass,0.0001),'-+b','0.0001')
l2=loglog(mass,f_lft(mass, 0.003),'-*r','0.03')
grid(True)
l3=loglog([10**-0.5,10**3],[10,10]) # Minimum timestep & the corresponding mass
xlim([10**-0.6,10**3])
ylim([10**0.2,10**5.5])
xlabel("Mass [$M_\odot$]")
ylabel("MS lifetime [$Myr$]")
title("Main Sequence lifetime against stellar Mass")


    

    















    












    
Out[8]:





<matplotlib.text.Text at 0x1115bff10>

In [71]:

    

# find y value at given x value
np.interp(100, xvalues, yvalues)


    

    
Out[71]:





3.492006252335163

In [ ]: