M42 - the Great Nebula in Orion is a large star formation region. It is fairly close, only about 1500 ly away.
The iron in iron meteorites was forged in the cores of massive stars. The meteorite itself is a remnant of the iron core from either a planetesimal or planet that formed in the early solar system that was then destroyed by a collision.
Globular clusters are balls of thousands to hundreds of thousands of generally older stars that orbit our Galaxy. We've also detected globular clusters orbiting other galaxies as well. Globular cluster M2 shown.
M51 or the Whirlpool galaxy is an interacting galaxy about 23 million light years from us.
For those interested in the memory stick, here's the website of artist who created it: http://www.byblackbirddesigns.com/Collections.html
The North America Nebula and the smaller Pelican Nebula (lower right) are actually part of the same large HII region. They appear separate because a dark nebula of dust and gas are between them and us, creating the shape of what we see as two individual nebulae. https://octodon.social/media/OLy3zEoSv4jgioDViM8
Hmmm getting 502 bad gateway errors when trying to upload pics here...
We classify stars based on their spectra. The sequence of spectral classes in essence tells us the temperature of the star. From hottest to coolest the classes are O, B, A, F, G, K, M.
Because of the distances involved the further we look into space, the farther back in time we are seeing. For every light-year away an object is, a year farther back in time is how we are seeing it. So an object 2000000 ly away we are seeing as it was 2000000 years ago.