five insights astronomers could glean from its latest data

The latest release of data from ESA’s Gaia spacecraft could support research ranging from expanding the universe to finding asteroid moons. (credit: ESA)

by Adam McMaster and Andrew Norton
Monday, June 20, 2022

The European Space Agency Mission Gaia just released new data. The Gaia satellite was launched in 2013, with the aim of measuring the precise positions of a billion stars. In addition to measuring the positions, velocities and brightness of stars, the satellite collected data on a wide range of other objects.

There’s a lot to excite astronomers. Here are five of our favorite insights the data could provide.

1. Secrets of our galaxy’s past and future

Everything in space moves, and stars are no exception. The latest release of the data contains the largest three-dimensional map of the Milky Way galaxy ever produced, showing how stars in our galaxy travel. Previous data included the motions of stars in two dimensions: up-down and left-right (known collectively as stars). appropriate movements). But the latest data also shows how fast stars are moving away from us or approaching us, what we call star radial velocities.

Discovering more quasars is important because it allows us to measure how fast the universe is expanding. It’s important to be able to measure this more accurately because we have two conflicting measures of expansion.

By combining radial velocity with the appropriate motions, we can find out how fast stars move in three dimensions as they orbit the Milky Way. This means that we now not only have the best map of the current location of stars in the galaxy, but we can follow their movements forward to see how things will change, and backwards to see how things were happening before.

It can tell us things about the history of our galaxy, like which stars may have come from other galaxies and merged with ours in the past. Radial velocity measurements can also help us find hidden objects, such as planets and brown dwarfs (extremely faint, low-mass stars), from the tiny oscillations they cause as they orbit a host star.

2. Star Death Details

Gaia not only measures stars in our own galaxy, it also measures those in the neighboring Andromeda galaxy. The data includes something called GAPS: the Gaia Andromeda photometric survey. A photometric survey measures the brightness of stars and their evolution over time. With GAPS, Gaia measured the brightness over time of each star in the direction of the Andromeda galaxy.

This includes 1.2 million stars. Some of these will be prominent stars in the Milky Way that were in the way, but this should include roughly the brightest 1% of stars in the Andromeda Galaxy. This will allow us to study how the largest and brightest stars in Andromeda change in brightness, telling us how they change and move through their life cycle.

This could tell us more about old stars coming to the end of their lives, some of which could eventually produce supernovae (huge explosions).

3. The truth about the strange expansion of the universe

Quasars, extremely energetic nuclei of galaxies on the periphery of the observable universe, are the brightest objects in the universe and the most distant objects we can see. And the new data includes the measurements of 1.1 million of them. Quasars contain supermassive black holes that are caught in a violent feeding frenzy. In addition to these confirmed quasars, Gaia has found an additional 6.6 million quasar candidates.

This potentially greatly increases the number of known quasars, and it could be very important because they allow us to measure the distance to the edges of the universe. This in turn allows us to measure the rate at which the universe is expanding. It is important to be able to measure this more precisely, because we have two contradictory measures of expansionand we don’t know which one is right – the problem is called “Hubble tension”.

4. How many asteroids have moons

Everything Gaia studies is not that far from home. The data contains 158,000 objects in our own solar system. This includes new measurements of 156,000 known asteroids, telling us exactly what paths they follow as they orbit the Sun.

This new data will excite astrophysicists around the world, and we can’t wait to dive into it to see what we can find.

Not only that, but the Gaia team has shown they are able to find moons orbiting asteroids, based on how moons make asteroids wobble. A few hundred asteroids with moons are already known, but Gaia can find asteroid moons even when the moon is too small to see directly. He can also measure the positions of asteroids with such precision that he sees the slight wobble in position caused by a moon’s gravity. The ESA says the latest data contains at least one such new moon, but there could be many more.

Collecting better asteroid data can tell us about the chaos of the early solar system when larger planets threw smaller planets and asteroids into new orbits around the Sun and led to today’s solar system. .

5. How stars form and function

Our Sun is a lone star, but many stars have companions in orbit around a shared center. The new data contains the first glimpse of Gaia’s catalog of these multiple star systems. This is an initial list, with the full catalog to come in a later data release, but it already contains 813,000 binary systems (two stars).

Binary stars can tell us a lot about how stars work and form. This is especially true for so-called eclipsing binary systems. They are binary systems that happen to be aligned so that the stars pass in front of each other from our perspective. Eclipsing binaries are special because we can take measurements from them to determine all the physical properties of the system, such as the masses and sizes of stars, and their distances. This allows us to learn much more than we could by studying single stars.

This new data will excite astrophysicists around the world, and we can’t wait to dive into it to see what we can find. We may have some of these answers in the next few months, while others may take longer.

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This article is republished from The conversation under Creative Commons license. Read it original article.

Andrew Norton is a PhD candidate in astronomy at the Open University, studying black holes and variable stars using citizen science. Andrew Norton is a Teaching Professor of Astrophysics at The Open University, whose research interests cover various aspects of time domain astrophysics with a current focus on stellar photometry from wide field surveys to study nearby binary stars.

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