What are the approximate limits of how far we can say we know all the stars of a certain type within?
E.g. what's the closest distance there could be an undiscovered G-class dwarf star, or a W Ursae Majoris system of comparable luminosity?
Thanks for any help.
Limit of knowledge of star types
It one point I tired to compile a definitive list of all star types, and their approximate size and temperature. You can find the file here However during my research it turns out that apparently the class of a star is somewhat subjective, and no one can quite agree at what point a star becomes classified as a different type. In the Hertzsprung-Russell Diagram I find it lacking it one key area which might make the diagram universal and all stars 100% predictable, and that is the composition of the star. Literarily adding 1% additional helium will make a star slightly cooler enough to throw of the temperature into a lower star class, but the on the HR scale, but its size and brightness classify it as different star class. I hope this helps. However our understanding in general is far from complete. We still do no know the absolute lower limit nor the upper limit of star formation. I was once though that ~75 solar masses was the absolute maximum a star could get before it would tear itself apart due to the energy being released. Sure enough around Sagittarius A* they found a star with an estimated 120 solar mass.
FWIW, Jahreiss & Wielen (1997) estimate that the Hipparcos database is complete for all stars brighter than Mv=8.5 within 25 parsecs. That's 1477 stars.
(I came across this statement in http://www-int.stsci.edu/~inr/pmsu4.html )
Of course, that doesn't really answer your question.
(I came across this statement in http://www-int.stsci.edu/~inr/pmsu4.html )
Of course, that doesn't really answer your question.
Selden