New models suggest that the Milky Way is not as full of stars as previously thought

A small team of astronomers from Yunnan University, the University of Utah, New Mexico State University and the University of St Andrews created a new model of the Milky Way galaxy based on the results of their census of red giants.

In his article published in the journal natural astronomy, the group describes how their model showed that there may not be as many stars in the galaxy as thought.

As the research team notes, our solar system resides on one arm of the Milky Way galaxy, quite far from the galactic bulge and the supermassive black hole believed to be at its center. They note that such an advantageous position makes it very difficult to accurately discern its structure.

Estimates of its structure were based on estimates of the number of stars in different parts of the galaxy and then on estimates based on the structure of other galaxies. For this new study, the research team tried to refine these estimates by first taking a more precise census of red giants and using that data to create a model to estimate the shape and size of our galaxy.

To make their count, the team used different techniques to process data from the Galactic Evolution Observatory’s Apache Point experiment, allowing them to count red giants that are normally obscured by interstellar dust. This way they were able to get a more accurate count (nearly 250,000) and also more accurately place the red giants. And that allowed them to get a better picture of their distribution, especially in the bulge around the center of the galaxy.

After adding the data to their model, the research team found that the density of red giants tended to level off near the center between the edges of the galaxy and the bulge; a finding that differs from previous models, most of which had an exponential increase.

This finding, the researchers suggest, shows that the bulge is not as dense as previously thought. They also found that the radius of the galaxy’s light radius is roughly twice that estimated in earlier research efforts.

The team’s work shows that the stars in the galaxy are more spread out than previously thought, further suggesting that there may not be as many as thought. And if this is the case, it would mean that the Milky Way galaxy has less mass than previously calculated, which would mean that it may contain more dark matter than previous estimates have shown.

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