diff --git a/README.md b/README.md
index 73ebad32..993751e3 100644
--- a/README.md
+++ b/README.md
@@ -389,6 +389,7 @@ Use this if you are creating a star.
 - "size" : (decimal number)
 - "tint" : (colour) 
 - "solarFlareTint" : (colour) The flares are tinted weirdly so this won't make the actual colour of the star. You'll want to use trial and error to find something that matches.
+- "solarLuminosity" : (decimal number) Relative luminosity of this star compared to the sun.
 
 ### Signal
 - "signals" : (list of signal info objects)