def recombination(temperature):
    """
    Calculates the helium singlet and triplet recombination rates for a gas at
    a certain temperature.

    Parameters
    ----------
    temperature (``float``):
        Isothermal temperature of the upper atmosphere in unit of Kelvin.

    Returns
    -------
    alpha_rec_1 (``float``):
        Recombination rate of helium singlet in units of cm ** 3 / s.

    alpha_rec_3 (``float``):
        Recombination rate of helium triplet in units of cm ** 3 / s.
    """
    # The recombination rates come from Benjamin et al. (1999,
    # ADS:1999ApJ...514..307B)
    alpha_rec_1 = 1.54E-13 * (temperature / 1E4) ** (-0.486)
    alpha_rec_3 = 2.10E-13 * (temperature / 1E4) ** (-0.778)
    return alpha_rec_1, alpha_rec_3