A detailed 3D map of the Milky Way unveiled by astronomers

The bounty is due to the Gaia mission of the European Space Agency, which has spent 6.5 years monitoring stars in and beyond our Milky Way galaxy. Using the observations of the spacecraft, researchers will create a detailed 3D map of stars and find patterns played out around the galaxy.

Anthony Brown, an astronomer at the University of Leiden in the Netherlands and chair of the Gaia Data Processing and Analysis Consortium Executive Committee, told Space.com, "Essentially all of the astronomy benefits from this one way or another because it's very fundamental data," "It's a very very broad survey mission."

Of course, observing 1.8 billion stars is amazing, but the heart of the mission's science is the statistical analysis allowed by such vast quantities of data. "I think the precise number doesn't matter so much," Brown said. "We're still only observing probably about 1 percent of all the stars in the Milky Way, even with this enormous number."

While today is the first opportunity for scientists to publicly access the details, Gaia team members have already dug through it to perform some initial analyses. One consequence of that work is that scientists have measured how the solar system, a tiny phenomenon, is accelerating in its Milky Way orbit.

To do so, Gaia has observed more than a million quasars situated so far away that they should not appear to be moving, light objects at the center of galaxies. But they do, and in a pattern that points to the middle of the Milky Way's center and shows all the numerous tiny tugs from nearby objects that the solar system encounters.

The effect is a value that is a fraction of a meter, estimated with an even smaller accuracy, an eye-watering small number that could not be significantly determined until the release of the new data.

Brown said of the calculation, "It's amazing that one can do this,"

And that's just the start. Today's data is the third find of the Gaia spacecraft and contains observations worth almost 3 years, less than half of what has been obtained so far. (The disconnect stems from the sheer bulk of data gathered by Gaia and the processing work that must be performed by 400 team members across Europe to convert it into public results.) And at least two more releases of data are expected, probably more if the task of Gaia is extended to last a full decade.

The previous data release allowed scientists to track the history of the Milky Way formation, Brown said, among many other studies. Those measurements identified the most recent significant fusion of the Milky Way, about 10 billion years ago. More recently, as a nearby dwarf galaxy has been slowly torn apart by the Milky Way, the interactions seem to coincide with the bursts of star formation in the Milky Way, another type of galactic shaping.

Brown highlighted a different result from the previous data to demonstrate the kind of research that Gaia can promote the superdense cores of stars like our sun that have lost their outer layers and run out of fuel, based on observations of white dwarfs.

Scientists could distinguish brightness levels in Gaia's measurements of the luminosity and temperature of these stars at which the normally dimming stars appear to hover for a while before starting to fade. And that, Brown, said is evidence that carbon and oxygen are crystallizing deep inside those stars, which scientists have long predicted but could not detect.

Brown said, "I like this result a lot because we start out by saying, 'OK let's see out how far away these things are' and you end up looking in the interior and proving that they crystallize," "This was predicted 50 years ago, but this is the first time we can prove it with observations that it's happening."

And today scientists have the data to play with even more powerfully.


Publish : 2020-12-03 18:28:00

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