The upper mass limit for a neutron star is theorized to be around 2 solar masses, while the upper mass limit for a white dwarf is approximately 1.4 solar masses. This information aligns with current astrophysical understanding, although the source referenced is nine years old. The discussion confirms the 2 solar masses figure for neutron stars as accurate. Overall, the conversation centers on clarifying the mass limits of these stellar remnants. Accurate knowledge of these limits is essential for understanding stellar evolution.