Celestia Forums

This is a question that is puzzling me and other OA members; I've done a bit of Googling, and I have come up with a wide range of answers, between 0.02 and 0.6(!);

what is the population density of the galaxy in stars per cubic light year, particularly in the region of the Sun?

Including the dimmest of red dwarfs, if possible - but perhaps figures won't be available for those objects, seeing as we are still discovering them relatively near Sol.

You've got to be careful with these data - even astronomers sometimes say "stars per cubic parsec" when they mean "stellar systems per cubic parsec" or even "solar masses per cubic parsec", which leads to endless confusion. That said, I can't imagine why all your numbers have come out so high.

There are problems with brown dwarfs, since it's likely some nearby brown dwarfs haven't been identified. But the RECONS survey lists 101 stellar systems consisting of 146 stars, in a sphere 22.29 light years in radius centred on the Sun - that's 0.002 systems per cubic light year, and 0.003 stars per cubic light year. That's a little lower than the average for this part of the galactic disc, which is quoted in the current edition of Allan's Astrophysical Quantities as being 0.14 stars per cubic parsec = 0.004 stars per cubic lightyear. (Masses over 0.08 solar masses, ie no brown dwarfs.)

Grant

Thank you; that sounds like what I needed-
here are two other figures which are quite wide of the mark, it seems.
http://www.sciencenet.org.uk/database/p ... 1287d.html
http://home.cwru.edu/~sjr16/advanced/st ... sters.html

steve