why are dwarf stars hotter then normal stars

Question: why are dwarf stars hotter then normal stars
- Keywords:
  dwarf star,
  space,
  star
Asked by phoebephenix to Asif, Laura, Lena, Sean, Viv on 14 Mar 2012.
- Laura Waters answered on 14 Mar 2012:
  
  Some are not very hot at all!
  Read this:
  http://news.nationalgeographic.com/news/2011/03/110323-coldest-star-discovered-cup-coffee-brown-dwarf-hawaii-space-science/
- Lena Ciric answered on 14 Mar 2012:
  
  What do you mean by normal star?
  
  Dwarf stars include stars that are not that bright and are an average size. Our own Sun is also a type of dwarf star.
- Sean Murphy answered on 14 Mar 2012:
  
  We are still learning much about what a star is. Every time we think we know what “normal” is, we find new stars that tell us we were wrong.

Question: why are dwarf stars hotter then normal stars