With the help of NASA's Hubble Space Telescope and the European Space Agency's Gaia satellite, scientists recently calculated that the mass of the Milky Way is 1.54 trillion
solar masses. This weight is more than 700 billion times the mass of the sun!
Earlier research dating back several decades used a variety of observational techniques that provided estimates for our galaxy's mass ranging between 500 billion to 3 trillion
solar masses. The improved measurement is near the middle of this range.
The orbital motions of stars around the Milky Way center indicate the presence of a massive black hole with about 4.5 million
solar masses, which is spatially coincident with Sgr A* [2-3].
Solar mass stars create planetary nebulae and become white dwarfs.
At the center of the S106 region is IRS4, a massive star born some 100,000 years ago with a
solar mass of about 20 times that of the sun.
The difference between these approaches regards the value of the limit that can change from 0.7
solar masses in the Oppenheimer-Volkoff (O-V) model to few
solar masses in the other models [12].
In stars of several
solar masses, H burning occurs at a furious pace.
The innermost stars of our Galaxy, called S-stars, are in Keplerian orbits about a proposed [1] black hole of mass 4.3 [+ or -] 0.3 million
solar masses. Their orbital planes appear to have random orientations, their orbital eccentricities range from 0.131 to 0.963 with no apparent pattern, and their origins of formation remain an issue.
Figure 1 plots the density of a black hole as a function of its mass in the unit of the
solar mass (the solid line) or a function of its radius in the unit of 3 kilometers (the same line).