Companion ejection velocity seems to be a factor of 2 too large

[TomWagg]

Describe the bug
The ejection velocity of secondary stars seems to be a factor 2 larger than one would expect when comparing to their pre-superova orbital velocities.

Label the issue
urgency_low - This issue is not urgent
severity_minor - This is a minor bug with minimal impact

To Reproduce
As an example, run a grid of binaries with m1=20, m2=15, porb=100d, Z=0.02, each time with a different random kick. Then compare these vaues from the BSE_SUPERNOVAE table for the first supernova: ComponentSpeed(CP) to Orb_Velocity<SN * (Mass_Total@CO(SN) / (Mass_Total@CO(SN) + Mass(CP))). The ratio of these two values is ~2 on average.

Expected behavior
I'd expect that

Screenshots
Here's a histogram of the ratio that I'd expect to be centred around 1

Versioning (please complete the following information):

• OS: Ubuntu 22.04
• COMPAS: v03.01.10

Code snippet for processing data

    df_dict = {}

    with h5.File("COMPAS_Output.h5") as f:
        print(f.keys())
        print(f["BSE_Supernovae"].keys())

        for k in f["BSE_Supernovae"].keys():
            df_dict[k] = f["BSE_Supernovae"][k][...]
    df = pd.DataFrame(df_dict).set_index("SEED", drop=False)
    df = df.drop_duplicates(subset="SEED", keep="first")

    print(f'Disruption rate: {100 - ((df["Unbound"] == 0).sum() / len(df) * 100)}%')

    v_orb_2 = df["Orb_Velocity<SN"] * (df["Mass_Total@CO(SN)"] / (df["Mass(CP)"] + df["Mass_Total@CO(SN)"]))
    v_orb_2 = v_orb_2.iloc[0]
    print(f"v_orb_2 = {v_orb_2}")

    natal_kicks = df.rename(columns={"ComponentSpeed(CP)": "vsys_2_total",
                                     "Applied_Kick_Magnitude(SN)": "natal_kick",
                                     "Unbound": "disrupted"})

    plt.hist(natal_kicks["vsys_2_total"][natal_kicks["disrupted"] == 1] / v_orb_2, bins=80, range=(0, 4))
    plt.xlabel(r"$v_{\rm 2, postSN} / v_{\rm 2, preSN}$ (km/s)")
    plt.show()