Q840775

NGC 2438 is a planetary nebula in the southern constellation of Puppis. Parallax measurements by Gaia put the central star at a distance of roughly 1,370 light years. It was discovered by William Herschel on March 19, 1786. NGC 2438 appears to lie within the cluster M46, but it is most likely unrelated since it does not share the cluster's radial velocity.

The object is a multi-shell planetary nebula with a bright inner nebula with a diameter of 60″, consisting of two somewhat detached shells. It is expanding with a velocity of 37 km/s. The structure is surrounded by a fainter, mostly circular halo that is more visible on the western half, and has a diameter of 130″. The mass of the main nebula is estimated at 0.45 M☉, while the shell has 0.5–0.8 M☉. The main nebula has a temperature of about 10–13,000 K, rising to 15–17,000 K at the inner edge.