astropy · nsabrams · Jan 27, 2026 · Jan 27, 2026 · Jan 27, 2026 · Jan 27, 2026
diff --git a/docs/Cluster_w_COSMIC.ipynb b/docs/Cluster_w_COSMIC.ipynb
diff --git a/docs/atmo_models.rst b/docs/atmo_models.rst
@@ -4,7 +4,7 @@
 Atmosphere Model Object
 ========================================
 Stellar atmosphere models are defined as functions in
-``popstar/atmospheres.py``. These can be called by::
+``spisea/atmospheres.py``. These can be called by::
 
  from popstar import atmospheres
  atmo = atmospheres.<function_name>

diff --git a/docs/contributors.rst b/docs/contributors.rst
@@ -19,7 +19,7 @@ Dongwon Kim -- code testing/debugging
 Siyao Jia -- helped with early code and documentation development
 
 Natasha Abrams -- developed resolved multiplicity capabilities
-(ResolvedMultiplicityDK class)
+(ResolvedMultiplicityDK class) and added COSMIC support.
 
 Michael Medford -- developed resolved multiplicity capabilities
 (ResolvedMultiplicityDK class)
@@ -50,4 +50,4 @@ and increased filter name flexibility for synphot
 
 Anna Pusack -- Added IRTF L-band filter support
 
-Caitlin Begbie -- added brown dwarf physics and capabilities
+Caitlin Begbie -- added brown dwarf physics and capabilities
diff --git a/docs/contributors_BACKUP_57328.rst b/docs/contributors_BACKUP_57328.rst
diff --git a/docs/contributors_BASE_57328.rst b/docs/contributors_BASE_57328.rst
diff --git a/docs/contributors_LOCAL_57328.rst b/docs/contributors_LOCAL_57328.rst
diff --git a/docs/contributors_REMOTE_57328.rst b/docs/contributors_REMOTE_57328.rst
diff --git a/docs/evo_models.rst b/docs/evo_models.rst
@@ -73,11 +73,18 @@ Below is a table of the evolution model grids currently supported by SPISEA.
      - 6.00 - 10.00
      - -0.5, 0, 0.5
      - Marley et al. (2021)
+   * - ``COSMIC`` :sup:`b`
+     - 0.08 - 150
+     - -
+     - -2.3 - 0.18
+     - Breivik et al. (2020)
 
 .. rubric:: Footnotes
 
 :sup:`a` Actual maximum value given by the Sonora models (Marley et al., 2021) relies on the age of the cluster. For example, for log(Age)=6.0, the mass range is limited to 0.0005 - 0.011 M\ :sub:`⊙`.
 
+:sup:`b` COSMIC evolves the stars externally and does not use SPISEA's standard isochrone-grid architecture. Instead, it uses a custom atmosphere grid that is created on the fly. See Breivik et al. (2020) for more details on COSMIC. When COSMIC is used, the IFMR is ignored.
+
 Please note the stellar mass range, age range, and metallicity values of the evolution
 model grid you choose:
 
@@ -142,4 +149,7 @@ Specific Evolution Model Classes
 	       :show-inheritance:
 
 .. autoclass:: evolution.Phillips2020
+	       :show-inheritance:
+
+.. autoclass:: evolution.COSMIC
 	       :show-inheritance:
diff --git a/docs/make_isochrone.rst b/docs/make_isochrone.rst
@@ -89,11 +89,18 @@ Tips and Tricks: The IsochronePhot Object
     reddening law have changed, the original file will be overwritten
     by the new isochrone.
 
-    *To avoid files from being unintentially overwritten, we recommend
+    *To avoid files from being unintentionally overwritten, we recommend
     that users specify different iso_dir paths when making isochrones
     with different evolution models, atmosphere models, or reddening
     laws.*
 
+* For external evolution models (i.e. COSMIC), you should use 
+  IsochronePhotExternalEvolution
+  instead of IsochronePhot. This is because those evolution models do not have isochrones but
+  instead evolve the stars externally. The first time you run a new AKs, metallicity, or distance,
+  this will take ~10-20 mins because it is creating a new atmosphere grid. This table is saved in the 
+  specified iso_dir, under the filename atm_<aks>_<dist>_<z>.fits.
+
 Base Isochrone Class
 ----------------------------
 .. autoclass:: synthetic.Isochrone
@@ -108,6 +115,10 @@ Isochrone Sub-classes
 	       :show-inheritance:
 		:members: make_photometry, plot_CMD, plot_mass_magnitude
 
+.. autoclass:: synthetic.IsochronePhotExternalEvolution
+	       :show-inheritance:
+		:members: make_photometry, plot_CMD, plot_mass_magnitude
+
 
 Photometry Conversion Functions
 -----------------------------

diff --git a/docs/multiplicity.rst b/docs/multiplicity.rst
@@ -27,6 +27,11 @@ returned in the ``star_systems`` table off the cluster object is the
 same for both unresolved and resolved multiplicity classes: it
 represents the combined photometry of all stars within a given system.
 
+For most selected evolution models, the multiples are evolved as single stars.
+To evolve binaries (does not support higher order multiples), you should use one of the ``MultiplicityResolved`` classes
+and the ``COSMIC`` evolution model. 
+See the example jupyter notebook `Cluster_w_COSMIC.ipynb <https://github.com/astropy/SPISEA/blob/main/docs/Cluster_w_COSMIC.ipynb>`_ for an example.
+
 
 Unresolved Multiplicity Classes
 ------------------------------------------