HelperFunctions.py 文件源码

def get_max_separation(p_spt, s_temp, v, d=1.0 * u.parsec):
    """
    Get the maximum separation for a binary candidate
    :param p_spt:   The spectral type of the primary star
    :param s_temp:  The temperature of the companion
    :param v:       The velocity, in km/s, of the companion
    :param d:       The distance, in parsec, to the system
    :return:        The maximum primary-->secondary separation, in arcseconds
    """
    # Convert the companion temperature and primary spectral type to mass
    from kglib.spectral_type import Mamajek_Table

    MS = SpectralTypeRelations.MainSequence()
    MT = Mamajek_Table.MamajekTable()
    teff2mass = MT.get_interpolator('Teff', 'Msun')
    M1 = MS.Interpolate('mass', p_spt)
    M2 = teff2mass(s_temp)
    Mt = (M1 + M2) * u.M_sun

    # Compute the maximum separation
    G = constants.G
    a_max = (G * Mt / v ** 2)
    alpha_max = (a_max / d).to(u.arcsecond, equivalencies=u.dimensionless_angles())
    return alpha_max