[jwuphysics]

There is indeed lots of uncertainty, and all Milky Way mass estimates are model dependent. Also, the ~10^12 solar mass figure referred to above is an estimate of the total galaxy + dark matter halo mass. Stellar or baryonic mass estimates are closer to ~6 x 10^10 solar masses. I'm using "~" to mean uncertainty to within a factor of 2 or so.

[auxbuss]

Stacy McGough wrote about this topic recently wrt the third Gaia data release: https://tritonstation.com/2023/09/19/recent-developments-con...