# Brown Dwarf

• Between roughly $\frac{1}{100}$ and $\frac{1}{2}$ the mass of the Sun
• May produce energy for a brief time by means of nuclear reactions involving deuterium
• Do not become hot enough to fuse protons
• Similar to Jupiter in radius
• Difficult to observe because they are faint and cool
• Put out most of their light in the infrared spectrum\