Python constants.M_sun方法代码示例

# 需要导入模块: from astropy import constants [as 别名]
# 或者: from astropy.constants import M_sun [as 别名]
def stellar_info(chain, data):

    """
    computes stellar masses and SFRs
    """

    gal_do,  irlum_dict, nh_dict, BBebv_dict, SFRdict = data.dictkey_arrays #call dictionary info

    #relevanta parameters form the MCMC chain
    tau_mcmc = chain[:,0]     
    age_mcmc = chain[:,1] 
    GA = chain[:,6] - 18. #1e18 is the common normalization factor used in parspace.ymodel in order to have comparable NORMfactors    

    z = data.z
    distance = z2Dlum(z)

    #constants
    solarlum = const.L_sun.to(u.erg/u.second) #3.839e33
    solarmass = const.M_sun

    Mstar_list=[]
    SFR_list=[]


    for i in range (len (tau_mcmc)):        
        N = 10**GA[i]* 4* pi* distance**2 / (solarlum.value)/ (1+z)

        gal_do.nearest_par2dict(tau_mcmc[i], 10**age_mcmc[i], 0.)
        tau_dct, age_dct, ebvg_dct=gal_do.t, gal_do.a,gal_do.e
        SFR_mcmc =SFRdict[tau_dct, age_dct]

        # Calculate Mstar. BC03 templates are normalized to M* = 1 M_sun. 
        # Thanks to Kenneth Duncan, and his python version of BC03, smpy
        Mstar = np.log10(N * 1) 
        #Calculate SFR. output is in [Msun/yr]. 
        SFR = N * SFR_mcmc
        SFR_list.append(SFR.value)    
        Mstar_list.append(Mstar)    

    return np.array(Mstar_list)    , np.array(SFR_list) 

# 需要导入模块: from astropy import constants [as 别名]
# 或者: from astropy.constants import M_sun [as 别名]
def distForces(self, TL, sInd, currentTime):
        """Finds lateral and axial disturbance forces on an occulter 
        
        Args:
            TL (TargetList module):
                TargetList class object
            sInd (integer):
                Integer index of the star of interest
            currentTime (astropy Time):
                Current absolute mission time in MJD
                
        Returns:
            tuple:
            dF_lateral (astropy Quantity):
                Lateral disturbance force in units of N
            dF_axial (astropy Quantity):
                Axial disturbance force in units of N
        
        """
        
        # get spacecraft position vector
        r_obs = self.orbit(currentTime)[0]
        # sun -> earth position vector
        r_Es = self.solarSystem_body_position(currentTime, 'Earth')[0]
        # Telescope -> target vector and unit vector
        r_targ = TL.starprop(sInd, currentTime)[0] - r_obs
        u_targ = r_targ.to('AU').value/np.linalg.norm(r_targ.to('AU').value)
        # sun -> occulter vector
        r_Os = r_obs.to('AU') + self.occulterSep.to('AU')*u_targ
        # Earth-Moon barycenter -> spacecraft vectors
        r_TE = r_obs - r_Es
        r_OE = r_Os - r_Es
        # force on occulter
        Mfactor = -self.scMass*const.M_sun*const.G
        F_sO = r_Os/(np.linalg.norm(r_Os.to('AU').value)*r_Os.unit)**3. * Mfactor
        F_EO = r_OE/(np.linalg.norm(r_OE.to('AU').value)*r_OE.unit)**3. * Mfactor/328900.56
        F_O = F_sO + F_EO
        # force on telescope
        Mfactor = -self.coMass*const.M_sun*const.G
        F_sT = r_obs/(np.linalg.norm(r_obs.to('AU').value)*r_obs.unit)**3. * Mfactor
        F_ET = r_TE/(np.linalg.norm(r_TE.to('AU').value)*r_TE.unit)**3. * Mfactor/328900.56
        F_T = F_sT + F_ET
        # differential forces
        dF = F_O - F_T*self.scMass/self.coMass
        dF_axial = (dF.dot(u_targ)).to('N')
        dF_lateral = (dF - dF_axial*u_targ).to('N')
        dF_lateral = np.linalg.norm(dF_lateral.to('N').value)*dF_lateral.unit
        dF_axial = np.abs(dF_axial)
        
        return dF_lateral, dF_axial