constellation
A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object.
The origins of the e ...
Puppis
Puppis is a constellation in the southern sky. Puppis, the Latin translation of "poop deck", was originally part of an over-large constellation Argo Navis (the ship of Jason and the Argonauts), which centuries after its initial description, was ...
. It has an apparent visual magnitude of 6.9, an angular size of 10 arcminutes, and is visible using a small telescope. This is a young cluster with age estimates in the range of 20–300 million years. It has a
tidal radius
A globular cluster is a spheroidal conglomeration of stars. Globular clusters are bound together by gravity, with a higher concentration of stars towards their centers. They can contain anywhere from tens of thousands to many millions of membe ...
of approximately 82
light year
A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 1012 ...
s. No chemically peculiar stars have been found.
Distance estimates to this cluster vary widely. Piskunov and associates (2008) gave an estimate of . A value in the range 3–4 kpc means the cluster lies well below the Galactic Plane. It is positioned in a hole in the Milky Way's gas and dust, with the reduced absorption resulting in a lower than expected extinction of 1.27 in visual magnitude. This result raises the question of whether this cluster actually exists. It is positioned along the same line of sight as two groups of B-typesupergiant stars. The nearer group is located at a distance of 1.03 kpc, while the second group is at 3.2 kpc.
Gallery
File:NGC 2439 map.png, Map showing the location of NGC 2439