Castor, which is actually a sextuple star system, can be seen as is a fine, close double star in small telescopes. (Credit: Damian Peach) Mona Evans, "Gemini - the Celestial Twins" http://www.bellaonline.com/articles/art182821.asp
Procyon, the seventh brightest star in the sky and one of the vertices of the Winter Triangle. It's one of our nearest neighbors at just over 11 light years away in the constellation Canis Minor. Procyon is a binary star system, composed of a white main sequence star and a white dwarf star.
Arcturus – Sun comparison. (Illustration – Bob King) The Sun looks very small compared to red giant Arcturus. Mona Evans, "How Big Are the Biggest Stars" http://www.bellaonline.com/articles/art300366.asp
The nearest stars, their distances in light-years, spectral types and known planets. Only 9 of the stars within 15 light years can be seen with the unaided eye from Earth. (Credit: Karl Tate / Source: NASA)
Classification of Stars. At the top of this diagram are the Main Sequence stars, those using hydrogen as their nuclear fuel. The Sun is a G-type star, so you can compare that to the rare O-type stars to see the difference in size. And the difference in mass can be up to 100 times. Mona Evans"How Big Are the Biggest Stars" http://www.bellaonline.com/articles/art300366.asp