I’m posting this because I find it crazy that I didn’t realize (or know) this until about a month ago.. If/when you jump into a completely (or partially but I’ll get to that next) unexplored system, your hud will only display the single star*, Nav panel will only have the main star, and system map will only have main star; if you don’t “honk”/FSS to see the systems body count, you could check all the above (Nav, system, hud) and leave without realizing the presence of additional bodies/stars.
Shortly after I realized this, I realized that the same was also true for partially discovered systems. I.E. I jumped into a system and hit the FSS, “36 bodies”, but I looked at my Nav panel and/or pulled up system map and there’s only 15 or such. Typically this seems to be situation s where a commander only FSS’d the planets of value and didn’t wanna spend/waste the time scanning 15+ Icy bodies, but I’ve also encountered systems where there’s significant parts that were missed (like a whole additional star and it’s orbiting bodies).
Hopefully this is old news to everyone but me, but for any new commanders who (like me admittedly) thought they could FSS, then check system map to see if any of the “unexplored” planets were worth attention, you can start paying attention to the body count and avoid missing out on some First Discoveries.