diff --git a/src/cosmic/sample/sampler/independent.py b/src/cosmic/sample/sampler/independent.py
index d0ba45d21..34923c709 100644
--- a/src/cosmic/sample/sampler/independent.py
+++ b/src/cosmic/sample/sampler/independent.py
@@ -971,12 +971,12 @@ def sample_porb(self, mass1, mass2, rad1, rad2, porb_model, porb_max=None, size=
         # of the period distribution there
         q = mass2 / mass1
         RL_fac = (0.49 * q ** (2.0 / 3.0)) / (
-            0.6 * q ** (2.0 / 3.0) + np.log(1 + q ** 1.0 / 3.0)
+            0.6 * q ** (2.0 / 3.0) + np.log(1 + q ** (1.0 / 3.0))
         )
 
         q2 = mass1 / mass2
         RL_fac2 = (0.49 * q2 ** (2.0 / 3.0)) / (
-            0.6 * q2 ** (2.0 / 3.0) + np.log(1 + q2 ** 1.0 / 3.0)
+            0.6 * q2 ** (2.0 / 3.0) + np.log(1 + q2 ** (1.0 / 3.0))
         )
 
         # include the factor for the eccentricity