62521
Elements that have been detected include sodium and potassium , produced by sputtering ( also found in the atmospheres of Mercury and Io ) ; helium-4 and neon from the solar wind ; and argon-40 , radon-222 , and polonium-210 , outgassed after their creation by radioactive decay within the crust and mantle .
 Mercury, Io
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Mercury, Io