Astronauts find a tiny Galaxy that has a darker path than we expected

A tiny old star called Tucana II that surrounds the Milky Way has been revealing a great secret. According to a new study of stars around the object, graphically attached to it at great distances, its dark subject halo is much larger than we thought.

In fact, it’s pretty big. While the stellar mass of Tucana II is about 3,000 times the mass of the sun, its dark matter clocks in at 10 million times the mass of the sun. That’s about three to five times more than previous estimates.

This suggests that the earliest galaxies in the Earth may have been much larger than we knew.

“Tucana II has a lot more mass than we thought, to connect those stars that are so far away,” said MIT astronaut Anirudh Chiti. “This means that other galaxies also appear to have the extended halos types as well.”

In the Milky Way there is a whole host of dwarf caterpillars. These are small, rather clustered clusters of stars that are very low in metal, appearing to be very old, as metals took time to form in the hearts of stars and move through the Universe. .

Tucana II, which is about 163,000 light-years from Earth, is among the smallest. Based on the metallurgy of the star population, it is also among the oldest, with almost no metals available. Chiti and his team were studying these stars, hoping to find a crowd of even older stars.

They checked using the SkyMapper telescope of the Australian National University and ran the results through a Chiti algorithm designed to select non-metallic stars. In addition to the stars inside the heart of Tucana II, the algorithm found nine new stars, at very long distances.

Data collected by Gaia satellite – an ambitious project to map the Milky Way in three dimensions, including the movements of the stars – confirmed e. These stars were far from the heart of the constellation in orbit around it, connected by a graph.

But the previously evaluated constructions of the galaxy did not contain enough mass to produce the kind of gravitational force that would keep the distant stars connected. This meant that there was some beauty that we did not see, or found directly. That, in turn, meant a dark matter.

We don’t know what a dark matter is, but there are some unseen masses out there in the Universe with a responsibility to create all the extra gravity, giving on galleries spinning faster, and space-time bends – and there’s a lot more of it than usual. That is a dark matter, and we believe that it is the glue that binds galleries.

“Without a dark case, galaxies would just fly apart,” Chiti said. “[Dark matter] it’s an important part of making a galaxy and keeping it together. “

Based on the position and movements of the stars, the team was able to update the estimate for the dark matter mass of Tucana II, eventually reaching the range of 10 million solar supplies. This is the first evidence that ultra dark galaxies can have that dark matter, and it raises a lot of puzzles.

“This may also mean that the earliest galaxies created in halos of dark matter were much larger than previously thought,” said MIT astronaut Anna Frebel. “We’ve always thought that the first galleries were the smallest, worst. But they were probably several times bigger than we thought, and they weren’t so tiny after all. everything. “

So where did he get that dark affair? There could be a glimpse of that in the galaxy’s stars. When the team examined data from the Magellan Telescopes in Chile, they found that not all stars have the same metallics.

In fact, they were very much divided between two peoples. The stars on the edge of Tucana II were three times lower in metallurgy than the stars in the center, suggesting two separate stellar groups. In the Milky Way, this can happen if crowds of stars have arrived from other places, such as collisions with another galaxy.

This is the first time that such a chemical distinction between stars has been seen in an ancient galaxy, but it is possible that the reasons are similar: once, Tucana II was not one, but two galaxies came together, combining their dark subject haloes.

“We may be seeing the first signature of galactic cannibalism,” Frebel said. “One galaxy may have eaten one of its slightly smaller, more primitive neighbors, which poured its stars into the periphery.”

However, it has happened, the research shows that the expanded reach of these small satellite galleries can now be seen and identified, which means that others like Tucana II could be identified. There are even two candidates – Segue 1 ultraviolet galaxy galaxies and Bootes Each has one star at a distance from the galactic core.

The team plans to use their techniques to find more such stars, and more such galaxies, and study them.

“There seem to be a lot more systems, probably all of them, that have these stars pushing the edge,” Frebel said.

The research was published in Astronomy of nature.

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