2024-01-26 11:41:06
A study by MIT physicists suggests that the Milky Way’s gravitational core may be lighter in mass and contain less dark matter than previously thought. – ESA/GAIA/DPAC
MADRID, 26 Ene. (EUROPA PRESS) –
MIT physicists have discovered that stars further away from the galactic disk travel more slowly than expected compared to stars that are closer to the center of the galaxy.
The findings raise a surprising possibility: The gravitational core of the Milky Way may be lighter in mass and contain less dark matter than previously thought.
The new results are based on the team’s analysis of data taken by the Gaia and APOGEE instruments. Gaia is an orbiting space telescope that tracks the precise location, distance and motion of more than a billion stars throughout the Milky Way, while APOGEE is a ground-based survey.
Physicists analyzed Gaia’s measurements of more than 33,000 stars, including some of the galaxy’s most distant stars, and determined each star’s “circular velocity,” or how fast a star rotates in the galactic disk, given the star’s distance from the center of the galaxy. .
The scientists plotted each star’s speed versus its distance to generate a rotation curve, a standard graph in astronomy that represents how fast matter rotates at a given distance from the center of a galaxy. The shape of this curve can give scientists an idea of how much visible and dark matter is distributed in a galaxy.
“What we were really surprised to see was that this curve stayed flat, flat, flat up to a certain distance, and then it started to sink,” he says. it’s a statement Lina Necib, assistant professor of physics at MIT. “This means that the outer stars are spinning a little slower than expected, which is a very surprising result.”
The team translated the new rotation curve into a dark matter distribution that could explain the slowing of the outer stars, and found that the resulting map produced a lighter-than-expected galactic core. That is, the center of the Milky Way It may be less dense and with less dark matter than scientists thought.
“This puts this result in tension with other measurements,” says Necib. “There’s something suspicious going on somewhere, and it’s really exciting to find out where it is, to really have a coherent picture of the Milky Way.”
The team reports its results this month in Monthly Notices of the Royal Society Journal.
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