Winnecke 4 (also known as Messier 40 or WNC 4) is an optical double star consisting of two unrelated stars in a northerly zone of the sky, Ursa Major.

The pair were discovered by Charles Messier in 1764 while he was searching for a nebula that had been reported in the area by Johannes Hevelius.

Data gathered by astronomers Brian Skiff (2001) and Richard L. Nugent (2002) strongly suggested the subject was merely an optical double star rather than a physically connected (binary) system.

[10] Parallax measurements from the Gaia satellite show the two stars, HD 238107 and HD 238108, are at distances of 311 ± 1 parsec (1,013 ± 4 light-years) and 144.2 ± 0.3 parsecs (470 ± 1 light-year) respectively.

HD 238108 is itself a genuine binary star, with an 18th magnitude white dwarf companion 5 arcseconds away and a parallax distance of 146.8 ± 2.3 parsecs (479 ± 8 light-years).