Editing Virial theorem (section)

=== Stars ===
The virial theorem is applicable to the cores of stars, by establishing a relation between gravitational potential energy and thermal kinetic energy (i.e. temperature). As stars on the [[main sequence]] convert hydrogen into helium in their cores, the mean molecular weight of the core increases and it must contract to maintain enough pressure to support its own weight. This contraction decreases its potential energy and, the virial theorem states, increases its thermal energy. The core temperature increases even as energy is lost, effectively a negative [[specific heat]].<ref name="BASUCHATTOPADHYAY2010">{{cite book|author1=BAIDYANATH BASU|author2=TANUKA CHATTOPADHYAY|author3=SUDHINDRA NATH BISWAS|title=AN INTRODUCTION TO ASTROPHYSICS|url=https://books.google.com/books?id=WG-HkqCXhKgC&pg=PA365|date=1 January 2010|publisher=PHI Learning Pvt. Ltd.|isbn=978-81-203-4071-8|pages=365–}}</ref> This continues beyond the main sequence, unless the core becomes degenerate since that causes the pressure to become independent of temperature and the virial relation with {{mvar|n}} equals −1 no longer holds.<ref name="Rose1998">{{cite book|author=William K. Rose|title=Advanced Stellar Astrophysics|url=https://books.google.com/books?id=yaX0etDmbXMC&pg=PA242|date=16 April 1998|publisher=Cambridge University Press|isbn=978-0-521-58833-1|pages=242–}}</ref>