NGC 2439 is an open cluster

Open cluster

An open cluster is a group of up to a few thousand stars that were formed from the same giant molecular cloud and have roughly the same age. More than 1,100 open clusters have been discovered within the Milky Way Galaxy, and many more are thought to exist...

 of stars in the constellation

Constellation

In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....

 Puppis

Puppis

Puppis is a constellation in the southern sky. Its name is the Latin word for the poop deck of a ship, and Puppis represents the deck of the ship and its deckhouses...

. It has an apparent magnitude of 6.9, an angular size of 10 arcseconds and is visible using a small telescope. This cluster is about 3.855 kpc from the Solar System and has an age of about 10 million years. Observationally, this cluster is along the line of sight of two groups of B-type supergiant stars. The nearer group is located at a distance of 1.03 kpc, while the second group is at 3.2 kpc.