Many stars form in clusters.
clusters are relatively young
swarms of bright stars
together near the plane of our Milky Way Galaxy.
Separated by about a degree on the sky, two
examples are M46
(upper left) 5,400 light-years in the distance
(lower right) only 1,600 light-years away toward
the nautical constellation
Around 300 million years
contains a few hundred stars in a region about 30 light-years
Aged 80 million years,
M47 is a
smaller but looser cluster
of about 50 stars spanning 10 light-years.
portrait of stellar youth also contains
an ancient interloper.
The small, colorful patch of glowing gas in M46 is actually
the planetary nebula NGC 2438 - the
final phase in the life of a sun-like star billions
of years old.
2438 is estimated to be only 3,000 light-years distant
and likely represents a foreground object, only by chance appearing
along our line of sight to youthful M46.