When it comes to size Betelgeuse has the radius of 820.9 million KM where as Barnard is a smaller than Betelgeuse with 136,400 KM radius.
In terms of color Betelgeuse is orange red and Barnard’s star is red in color.
Lifetime wise Barnard’s star is one of the oldest stars, older than sun that is 7.12 billion years where as Betelgeuse is less than 10 million years.
