The ESA Science & Technology video Gaia's asteroid discoveries shows trajectories for hundreds of asteroids that were seen by GAIA, but as far as I can deduce from the extensive notes there, only a small subset were actually discovered through GAIA observations.

Or it could be all of them and I'm misunderstanding the notes!

So I'd like to ask:

Question: How many asteroids were discovered via GAIA observations? Is there a list of them?

Animated view of more than 14 000 asteroids in our Solar System from the catalogue in the second data release of ESA's Gaia satellite, published in 2018.

The orbits of the 200 brightest objects are shown in green. In addition, the orbits of the first four asteroids discovered by Gaia are shown in pink.

While Gaia's main scientific goal is to chart a billion stars in our Milky Way galaxy, the satellite is also sensitive to celestial bodies closer to home, regularly observing known asteroids and occasionally discovering new ones.

Three of the newly discovered asteroids, temporarily designated as 2018 YK4, 2018 YL4 and 2018 YM4, were first spotted by Gaia in December 2018, and later confirmed by follow-up observations performed with the Haute-Provence Observatory in France, which enabled scientists to determine their orbits. Comparing this information with existing observations indicated the objects had not been detected earlier.

The fourth discovery, an asteroid with temporary designation 2019 CZ10, was first detected by Gaia in February, and was recently confirmed by ground-based observations by the Mount Lemmon Survey and the Pan-STARRS 1 project in the US.


1 Answer 1


In the video, the white dots represent 14000 asteroids, and the green tracks are 200 of the brightest asteroids. These are from standard catalogues.

Gaia has detected about 1700 asteroids, but most of these were already known. The video shows four newly discovered object, in pink. They have provisional designations 2018 YK4, 2018 XL4, 2018 YM4 and 2019 CZ10. By October 2020 a total of six had been identified in the data, and credited to Gaia, addtionally 2019 HO4 and 2018 XL20. (Note, there is an inconsistency between the sources here, with the video caption mentioning 2018 YL4. The published paper seems to be more authoritative, and I think YL4 is a typo on the video caption)

There are 133 other asteroids that are not attributed to Gaia (as they had been observed previously) but their previous observations had poorly determined their orbits. The Gaia observations "drastically improved their orbital elements".

There may be more that are in the data however I've been unable to find any update on this paper. At this time, it seems that 6 asteroids were discovered by Gaia. And 139 asteroids had their orbits established by Gaia.

However the Gaia follow-up network for solar system objects (Gaia-fun sso) continues to track and follow up detections of potential asteroids in Gaia data.

  • $\begingroup$ This is great! I couldn't make heads nor tails of the notes on the video. $\endgroup$
    – uhoh
    Dec 27, 2021 at 1:11

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