Madrid
Updated:
Save
The European Space Agency (ESA) has just released the latest data from the observation satellite Gaia. It is an extensive catalog with almost 2 billion stars of our galaxy, the Milky Way, the most accurate and complete to date. The map is accompanied by the publication of a fifty scientific articles.
Launched in 2013, Gaia operates in an orbit around the so-called Lagrange point 2 (L2), located 1.5 million kilometers behind Earth in the opposite direction from the Sun. There, the spacecraft remains in a stable position, which allows you to scan the sky continuously and without obstacles. Thanks to his work we can know the position and distance of each star in the same way that we know each block of flats in each one of the streets of a city.
Gaia’s two previous surveys – published in 2016 and 2018, as well as a subset of the third dataset in 2020 – identified the movement of the stars in our galaxy in great detail, which allowed to know how it has been transformed over time. But the latest observations, the third complete -collected between July 25, 2014 and May 28, 2017- add as a novelty details of chemical compositions, temperatures, colors, masses and ages of the stars, in addition to the speed at which that these are approaching or moving away from us (radial velocity). All this has been known thanks to spectroscopy techniques, where starlight is divided into different wavelengths.
“It’s like going from a black and white movie to a color movie. The data level is much more complete and the information is much more detailed,” José Hernández, Gaia calibration and operations engineer at ESA, tells this newspaper.
stellar earthquakes
One of the most surprising discoveries is that Gaia has been able to detect thousands of stellar earthquakes, something like large scale tsunami that change the shape of stars. And he has done it even in stars where, according to current theory, none should be recorded. These oscillations alter the overall shape of the star and are very difficult to detect.
“Gaia measures the spectrum of the stars, as if it were their fingerprint. It is so sensitive that it has found those that have significant stellar earthquakes, a catalog that can later be observed with other more specialized missions,” says Hernández. As Conny Aerts of the Catholic University of Louvain (Belgium) and a member of the collaboration states, the mission has opened “a gold mine for asteroseismology of massive stars.”
The DNA of the stars
By providing valuable information on the composition of stars, a kind of ‘DNA’, astronomers can learn their place of birth and their subsequent trajectory. Some stars in our galaxy are made of primordial material (light elements like hydrogen and helium formed after the Big Bang), while others, like our Sun, contain enriched matter from earlier generations (heavier elements called metals). Stars closer to the center and plane of our galaxy are richer in metals compared to those further away. Gaia has also identified stars that originally came from galaxies other than our own, based on their chemical composition.
“Our galaxy is a beautiful melting pot of stars,” says Alejandra Recio-Blanco, a member of the collaboration at France’s Côte d’Azur Observatory. “This diversity is extremely important, as it tells us the story of the formation of our galaxy. It reveals the migration processes and the accretion of external galaxies. It also clearly shows that our Sun and all of us belong to a constantly changing system, formed thanks to the meeting of stars and gas from different origins », he points out.
Clash with Andromeda
In other articles that have also been published this Monday, a catalog of binary stars is presented, with the mass and evolution of more than 800,000 systems of this type. Also included is a new study comprising 156,000 asteroids and that delves into the origin of our Solar System. In addition, it reveals information about 10 million variable stars, as well as about quasars and galaxies located beyond our own cosmic neighborhood. For example, a catalog of variable stars around the Andromeda galaxy is published. These data will make it possible to accurately determine its evolution until its encounter with our galaxy, something that will occur within 4,000 million years.
But, as Hernández says, the most surprising thing will come in the coming months, when scientists exploit the data released this Monday and obtain new conclusions. The map can help astronomers reconstruct the structure and past evolution of our galaxy over billions of years, as well as better understand the life cycle of stars and our place in the Universe. “We can’t wait to see how the astronomical community dives into our new data to learn more about our galaxy and its environment than we could ever imagine,” says Timo Prusti, Gaia Project Scientist at ESA.
The Gaia mission, which has a large Spanish participation, is expected to continue active until the spring of 2025, twice the time estimated at its origins. Then the catalog will exceed 2 billion objects. “Gaia has meant a before and after for astronomy, a revolution,” says Hernández. “Before we only knew a small part of the Milky Way very close to us, about a hundred thousand stars -he recalls-, and now we have covered half of the galaxy, 1% of all the stars it contains”. A sample “enough to understand in a very significant way the structure of our galaxy and how it was formed.”
See them
comments