Is the Sun just another star, or is it unique?
Before I answer, let me first explain some history.
When it comes to understanding science, the key is to understand that it is a puzzle, and we just trying to put the pieces together and see what we come up with. If the combo seems to fit, we go with it; if not, we reject it. Granted, it gets more complicated than that, but this is the idea.
So what of the Sun and stars?
Firstly we call them "Sun" and "stars" because those are the names passed down to us. (I've been in a science discussion about how the Sun and Moon should have a name the way the other bodies of the universe do. But it seems as if "Sun" and "Moon" are
their names, at least in English. This is why they are capitalized by some people.)
So, they studied the Sun and discovered certain properties. Then they studied the stars and discovered those same properties. From there it was concluded that they were the same thing (same material, same properties, etc.)
One thing to note about stars is that their are different spectral classes. These classes have been labeled: O, B, A, F, G, K, M (I know, you'd think they'd have come up with something better!). The O stars are the largest, brightest blue stars. The M stars the smallest, faint red stars.
In studying the stars this way, the sun shared the characteristics and traits of the G stars. G stars are yellow to white in color, for instance (the other traits would take some explaining...i.e. absorption lines of metals). All G stars have been measured to have the same weight and size range as well, and the calculations show our Sun to be in those ranges as well. Please do not, at this point, try to argue that the measurements are wrong unless you understand how the measurements were taken and can argue against them from that understanding, OK? I've taken a class on this, and I found that it is pretty amazing how light has been studied and applied!
So, when they say that the Sun is a star, it's because "the shoe fits."
If you want to read up more on the star classifications click here
Now about for your concern - is the Sun "just another star" or is it unique?
This is actually a question that some astronomers have debated among themselves, and I don't believe it is resolved.
You see, based on what knowledge we have on the stars, their temperatures and their lifespans (the large blue stars appear to have a shorter life than the smaller, cooler stars...because they burn out quicker - the way driving fast uses up gas quicker than driving slow), it has been determined that only G stars are capable of supporting life as we know it.
So whether or not other stars have planets or not, not all can support life.
At this point, let me save myself some effort and point you to what has been presented on this:
[b]Is the Sun unique as a star—and if so, why?
B Gustafsson 2008 Phys. Scr. T130 014036 (6pp); Department of Astronomy and Space Physics, Uppsala University
Abstract. The question whether the Sun is peculiar as compared with other stars in its neigbourhood is revisited. It is concluded that although the Sun is rather normal from many points of view, it departs in several respects from most stars of similar age and galactic orbit. Thus, it is more massive, and the amplitude of the micro-variability of the Sun at visual wavelengths seems unusually small. It also departs from most stars in being a single star, and it may have an unusual planetary system. There are some tentative indications that its chemical composition departs from those of most solar-type stars of similar age. This is discussed and the departures are found not to be significant. I discuss here to what extent these peculiarities may be understood in terms of it being a planet host.Source
~~~~~Is the Sun and Average Star?
OK, so there are some alternative perspectives to show you what I mean.
Hopefully, this will make sense to you.
Now, as for your bottom line concern about life existing around other stars? That's a new post for later.
I need to make some breakfast!