B Are the stars that we see in constellations within the Milky Way galaxy?

[snorkack]

At one end you need very bright stars to see them, and they are rare, and at the other end you need dim stars to be very close and they are rare too. (Trivia question: how many stars are visible to the naked eye and are dimmer than the sun?)

That depends on the magnitude threshold your eye and sky allow.
Adopting +6,00:

1. ε Eridani +3,73 +6,19
2. 61 Cygni +4,7 +7,5 (Not resolved by naked eye but combined magnitude is not commonly quoted. Simple mathematics but some taking of logarithms, so I rounded)
3. ε Indi +4,69 +6,89
4. τ Ceti +3,49 +5,68 the brightest of these, about nr. 280 of all stars
5. ο² Eridani +4,43 +5,93
6. 70 Ophiuchi +4,00 +5,66
7. σ Draconis +4,67 +5,87
8. 33 Librae +5,64 +6,79
9. 36 Ophiuchi +4,3 +6,2 (again AB combined magnitude rounded)
10. 279 Sagittarii +5,31 +6,41
11. e Eridani +4,26 +5,35
12. Gliese 892 +5,57 +6,49
13. ξ Bootis +4,7 +5,59
14. Gliese 105 +5,79 +6,50
15. 96 Piscium +5,74 +6,37
16. 107 Piscium +5,24 +5,86
17. μ Cassiopeiae +5,17 +5,78
18. p Eridani +5,0 +6,25
19. 61 Virginis +4,74 +5,09
20. 41 Arae +5,55 +5,83
21. 5 Capricorni +5,73 +6,00
22. κ¹ Ceti +4,84 +5,16
23. 66 Centauri +4,89 +5,06
24. 61 Ursae Majoris +5,31 +5,41
25. 289 Hydrae +5,97 +6,06
26. 12 Ophiuchi +5,77 +5,82
27. Gliese 75 +5,63 +5,61
28. α Mensae +5,09 +5,03 the dimmest lucida and the only lucida to be dimmer than Sun
29. 54 Piscium +5,88 +5,65
30. 11 Leonis Minoris +5,40 +5,16
31. ζ¹ Reticuli +5,52 +5,11. Note that ζ², resolved by naked eye, is so close to Sun in brightness that sources differ on which is the brighter
32. 85 Pegasi +5,81 +5,34
33. ρ¹ Cancri +5,96 +5,47
34. 285 Puppis +5,95 +5,45
35. 24 Virginis +5,54 +4,99
36. 86 Sagittarii +5,85 +5,28
37. 58 Eridani +5,63 +5,01
38. π¹ Ursae Majoris +5,63 +4,86
39. ψ Serpentis +5,86 +5,03
40. Gliese 1021 +5,80 +4,93

There is a possibility of a few more just beyond 15 pc, but likely not many.

 

[OmCheeto]

So it's really a remarkable coincidence that the curve looks so perfect, given the statistics.

I think it's just a happy coincidence.
Expanding the grouping to 34 points yields a much dirtier fit.

x-axis: 0.9 * ln( distance in light years )
y-axis: star count

Now if I can just figure out how to extract less than a billion data points from the Gaia database, I'll be able to make some more fancy graphs.