- Jonathan Amos
- BBC science correspondent
image source,ESA
Artist’s impression: European telescope probes the depths of the Milky Way
The latest batch of data has been released by Europe’s Gaia space telescope, which is building an up-to-date database of sources of cosmic light.
The space telescope has become an unparalleled machine, constantly reaping new discoveries.
Stars, meteorites and distant luminous galaxies, any space object that can be seen is observed and major data is recorded.
Gaia has scanned nearly 2 billion space objects. Space telescopes can now explain the makeup of these space objects.
Professor Nick Walton of the University of Cambridge, a member of the Gaia telescope research team, told the BBC: “In short, we used to be able to say exactly where they were; now we can tell you where they are. what is it?”
The European Space Agency (Esa) launched the Gaia satellite in 2013, sending the space telescope a million miles from Earth.
The space telescope is like a spinning top hat, and as it spins, the telescope uses a British-made 1-gigapixel camera to track any flashing or moving objects with astonishing precision.
Measuring the distances of these space objects is important. Space telescopes orbiting the sun measure the tiny wobble of these objects and use trigonometry to calculate the distances to 180 stars in, or near, the Milky Way.
- As Earth orbits the sun, relatively nearby stars appear to move, while more distant stars appear ‘fixed’
- After we know the distance from the sun to the earth, we can use the parallax angle to calculate the distance of the relevant star.
- But because this angle is so tiny, the nearest star shows a parallax angle of less than 1 arcsecond, or 0.05% of the full moon’s diameter
- Gaia can reduce the measurement error of a very bright star to 7 microarcseconds by repeating the observation
- This parallax method is also used in conjunction with other, more indirect techniques to measure the distances of the most distant space objects
image source,ESA/Gaia/DPAC
Constellation elements: different colors indicate that different constellations have different metallicities, and the reddish planets are iron-rich stars
In previous data released in December 2020, the Gaia space telescope also showed basic brightness and color information for the observed stars.
The new data shows spectral information.
The spectrum breaks light from a star into its different constituent colors, showing chemical information, temperature, volume, age and velocity of space objects.
For a significant subset of 33 million stars, Gaia researchers were able to quickly determine how fast those stars were moving away from, or approaching, Earth.
Based on what is known about the motion of space objects, researchers can now construct three-dimensional motion trajectories of these space objects.
This information gives researchers more motivation to probe the composition and evolution of the Milky Way, including its past and future.
Data from the Gaia Space Telescope now includes:
- 2 billion light sources – most of which are stars, but also many solar system objects and some extragalactic objects
- Spectral information, which shows the temperature, chemical composition, size and age of billions of space objects
- 1.9 million quasars – distant galaxies where phagocytic black holes drive light emission
- 156,000 asteroids – important to study their origin and possibility of passing near Earth
Many stars in the nearby Andromeda galaxy have been measured and their three-dimensional information is available, leading to an understanding of how and when these objects could fit into the Milky Way, which will happen in the next billions of years.
image source,ESA/Gaia/DPAC
Space telescopes can also detect stars moving away from us (bright regions) and stars moving toward us (dark regions)
One of the most surprising discoveries from these new data was the realization that the Gaia space telescope could do asteroseismology. The study of acoustic shocks on the surface of a planet allows researchers to obtain information such as the size and age of stars.
“Starquakes tell us a lot about stars, most notably about their internal activities,” said Connie Altz, a professor of astrophysics in Belgium. “The Gaia telescope has opened a gold mine for stellar shock studies on giant planets. ”
The latest batch of data released by the Gaia space telescope (this is the third comprehensive data release), the astronomy community around the world is immediately digging through the data for clues.
Some research teams already have papers ready and need Gaia’s data to complete their research.
For the competing teams, it becomes a race to get published first.
Hot topics of research include the search for high-velocity stars, which move through space at hundreds of kilometers per second.
Dr Timo Prusti, ESA’s Gaia project scientist, said: “The most likely scenario for these stars is that they are moving at such high speeds that they must be at the core of our galaxy, only in this This kind of acceleration is only possible under physical conditions.”
“So far these stars are more likely to be shortlisted because the Gaia telescope is not as capable (to have enough information on them), but I’m sure astronomers are ready to explore in the new data released by Gaia. “
Other hot topics to explore include whether those stars are rich in elements heavier than hydrogen and helium or are degenerating.
Metal-poor stars are of more interest to researchers because these stars may be very old, perhaps the earliest groups of stars that gathered to form the Milky Way.
The Gaia space telescope project began eight years ago, but the data released by the Gaia space telescope on June 13 represent only 34 months of the science project.
There are still 5 years of data that have been collected that have not been fully processed.
image source,ESA/Gaia/DPAC
Mapping stardust: the bar part of the galaxy has the most stardust (dark red); the upper and lower parts have less stardust (blue)
It is planned that the Gaia space telescope will scan and collect data in space until 2025. Before 2030 or the next 10 years, or even in the early 2030s, the data collected by the telescope will be fully put into the public domain.
Professor Gerry Gilmore from the University of Cambridge told BBC News: “What do you get out of that extra time? Certainly at least removes uncertainty. But the main takeaway is a heightened awareness of changing matters. sensitivity.”
“Especially with stellar oscillations, it can tell us that there are planets orbiting around the star.”
“If you only have one year of data, you can only find planets that are very close to the star.” “But with up to 10 years of observations, you find planets that are farther away from the star, and you find planet families.”
By the end of the Gaia mission, it will be able to confirm thousands of planets in the Milky Way.