Question

Which galaxy has the least stars per unit volume?

Answer 1

Abell 0194 (A194) or NGC 6822

Explanation:

After an intensive research on this strange topic, I found two probable answer to your questions. The link to the site is here. The link to referenced sources/studies are contained within the source website.

There is something out there called the mass-luminosity relation/mass-light ratio, which is the ratio of a galaxy's mass to the amount of light it emits (absolute magnitude). It is abbreviated as `M : L_(B)` or `M : L_(pg)`

So, we can assume this is the most reliable way to measure the number of stars in a galaxy to its volume. Since it is not easy to accurately estimate the number of stars and volume of a galaxy, especially if they are very far away.

In a paper published by Chincarini & Rood (1975), it states that the galaxy A194 has a `M : L_(pg)` of 31, which is very low in comparison to normal galaxies, which usually stays around 100.

However, I then found a table, also regarding the matter of mass to luminosity ratio. At the bottom of the table, it listed a galaxy called N6822, which is Barnard's galaxy. It has an astounding `M : L_(B)` of 0.58. But, it states it is the `M : L_(B)` of rotational curves, which means I could be totally wrong on this.

I am very unsure of such vague response, if anyone has reliable sources or answer, it would be great for everyone to check it out.