Are questions about the discoveries of DSOs common? I'm struggling to find information about that for most of them, and was wondering if it's particularly important to know.
The appear, but I wouldn't really consider them common. Most aren't that hard to find though, between Wikipedia and news articles you can usually get a date or year and a specific observatory or such.
Also, would there be questions about the sources of images, like "from what telescope did this image data come from" or "how big of an area does this image cover" or is it pretty much just "what DSO is this image of?"
Those are definitely viable questions, in addition to question about the spectral bands and general portions of the electromagnetic spectrum used in an image.
This is probably really really dumb, but do SN W49B and SN 1987A refer to the remnants of the supernovas (supernovae?) or the supernovas themselves? I assumed it had to be the remnants because they're objects, but the wikipedia page for SN 1987A refers to the actual supernova so I got confused. If it is the remnants, why do they use SN instead of SNR?
SN 1987A is the supernova, while SN W49B is the remnant. nomenclature is not necessarily helpful in Astronomy.
And a few questions about stellar evolution:
What is the relationship between HII regions and emission nebulae? I've found sites that have said a lot of different things including: the parts of HII regions that glow are called emission nebulae, they're the same thing, an HII region is a type of emission nebula, and HII regions exist in emission nebula areas... which, if any, is right? D:
Same thing with giant molecular clouds, stellar nurseries, and nebulae...are they the same things? Are they types of each other?? Are they related in any way???
A molecular cloud is a cloud of gas consisting almost exclusively of molecular hydrogen. When a section collapses and forms a star, the star formation (specifically, the ignition of fusion) creates a shock wave that propagates some distance through the cloud, ionizing it and turning it into an H II region (atomic H+
An emission nebula is any ionized cloud of gas - this includes the H II regions formed from star birth (the most common type of emission nebula) as well as those deriving energy from other sources. For example, a planetary nebula is ionized by the collapse of the star, but it is not an H II region because it doesn't involve stellar birth (according to the traditional narrow definition).
A stellar nursery is an ill-defined term for an area with many stars being formed. A nebula is just a general purpose term for a cloud of dust.