def area_over_choked_area(
        mach,
        gamma=1.4
):
    """
    Gives A/A^* (where A^* is "A-star"), the ratio of cross-sectional flow area to the cross-sectional flow area that would result in choked (M=1) flow.

    Applicable to 1D isentropic nozzle flow.

    Args:
        mach: Mach number [-]
        gamma: The ratio of specific heats. 1.4 for air across most temperature ranges of interest.
    """
    gp1 = gamma + 1
    gm1 = gamma - 1

    return (
            (gp1 / 2) ** (-gp1 / (2 * gm1)) *
            (1 + gm1 / 2 * mach ** 2) ** (gp1 / (2 * gm1)) / mach
    )