The use of tools for purposes that were not initially intended is a strength of the astronomical community. Exploring the data collected for one purpose and looking for clues to another seems to be the favorite pastime of many professional astronomers. This tradition is alive and well, with a team reviewing the first data sets from Gaia, ESA’s star cataloging explorer. They found evidence of exoplanets, and it turns out that the probe launched in 2013 is a much better planetary hunter than initially thought.
Gaia’s original mission was to track the stars very carefully. Initially, it aimed to create a catalog of more than a billion astronomical objects, from quasars to asteroids. So far, it has far exceeded expectations by cataloging only 1.8 billion stars. It does this with three main instruments. The astro is an astrometry instrument that measures the angular position of many of the stars it is observing. Photometry is covered by the BP / RP instrument, which measures the brightness of its subjects. Finally, the RVS instrument measures the speed at which objects reflect using the radial velocity technique.
The combination of data from these three instruments allows Gaia to detect how far away hundreds of millions of astronomical objects are and how fast they move. And it has fulfilled its original promise in a spectacular way, with its data supporting dozens of articles ranging from observations of globular cluster mergers to the faintest galaxy ever discovered.
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UT video talking about Gaia’s findings
But this is not all; the international team of researchers involved in the analysis and release of the Gaia datasets thought they might find other ghosts hidden in the star cataloger data. Thousands of exoplanets have been found so far, many using the radial velocity method to see how a star moves back and forth as the gravity of the orbiting planet causes it to move slightly in the sky. They believed that Gaia could do just that.
With Gaia’s super-precise instruments, it was well placed to detect tiny changes in a star’s position when it was disturbed by a planet. In fact, the team used photometric data sets from the boat’s three primary instruments. They then entered this data into a training algorithm that used the results of the TESS exoplanet survey to help train the algorithm on what to look for as a positive exoplanet finding.
What they did find were at least two new planets. Now known as Gaia-1 and Gaia-2, these two planets are both “Hot Jupiters”: giant planets that have such a fast orbital period that they are locked in their star. However, despite first appearing in Gaia’s data, the existence of the planets was confirmed by observations from TESS, a much more focused observatory on exoplanet hunting.
Collaboration with UT editor Fraser Cain and YouTuber Isaac Arthur.
TESS has a completely different underlying observation strategy than Gaia. It focuses on repeated, high-precision measurements of a star that could host a planet. Gaia, on the other hand, takes much less frequent pictures of its target as part of its sky observation requirements. That didn’t stop the researchers from trying, though. They managed to find that, even with Gaia’s scarce data points, they were able to detect not only the two new confirmed planets, but also 41 candidates for exoplanets that still need additional validation before being officially accepted into the ranks. of known exoplanets.
Overall, this is a great record for Gaia looking for things she wasn’t designed for. But there is still more to come, with the next release of data from Gaia, known as DR3, which is expected to be released in June this year. There is no doubt that even more exoplanets are expected to be found in new Gaia data with this newly trained algorithm.
More information: Panahi et al – Detection of exoplanets in transit by GaiaUT – The brightest star in the sky, Sirius, hid a cluster of stars. Found by GaiaUT – Gaia from ESA just took a picture of L2 neighbor JWSTUT – Gaia has already given us 5 new ideas about the Milky Way
Main image: Artistic concept of Gaia in space. Credits – ESA / D. Ducros
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