def return_closest_distance(binary):
    """
    Returns the closest component distance during eclipses.

    :param binary: BinarySystem;
    :return: float; distance in SMA units
    """
    conjunctions = binary.orbit.conjunctions
    conj_phases = [conj['true_phase'] for conj in conjunctions.values()]
    distances = binary.calculate_orbital_motion(conj_phases, return_nparray=True, calculate_from='phase')[:, 1]

    return distances.min()