Marco DELBO, the birth of planets: the planetesimals

  • Science and society
  • Research
Published on July 18, 2025 – Updated on July 18, 2025
Dates

on the July 7, 2025

Meet Marco DELBO, researcher and member of the LAGRANGE Laboratory at the Observatoire de la Côte d'Azur.

His research

At the LAGRANGE laboratory (Université Côte d'Azur, OCA, CNRS), Marco Delbo is working on one of the great questions of planetology: How do planets form?

More specifically, he is interested in planetesimals, the small primitive bodies formed from the dust of a protoplanetary disk, which constitute the building blocks of planets.

The ANR ORIGINS project he is coordinating seeks to fill a crucial data gap for theoretical models: the size, composition, distribution and origin of planetesimals. In particular, it aims to find out:

  • Did they form directly with large sizes (from the start ~100 km) or did they grow gradually?
  • What was their chemical composition?
  • What role did they play in the early phases of orbital instability of the planets in the solar system?
  • How were they dispersed and redistributed in the various regions of the protoplanetary disk?

To answer these questions, two French laboratories have developed a new direct observation method for identifying primitive planetesimals among asteroids. The method involves eliminating asteroids formed by collisions, to reveal the original objects in the main belt.
Thanks to this approach, several primitive objects have already been discovered, and the project now plans a systematic analysis of the entire asteroid belt (over 60,000 objects), exploiting in particular spectroscopic data from ESA's Gaia mission.

The project combines several disciplines: orbital dynamics, astronomical observations, cosmochemistry and data science. It also contributes to the training of young researchers and the preparation of new space missions to study the oldest bodies in the solar system.

His inspiration

"I've always loved astronomy and physics; I've always hoped to be able to work with telescopes and study the cosmos, but becoming a researcher I don't see as a goal. "

Results and prospects

In addition to his systematic study of asteroids and the identification of the most primitive objects, this research will be used to design new space mission projects dedicated to finding, studying and sampling the bodies hosting the most primitive matter in our solar system.

Marco Delbo explains the ORIGINS project in more detail in his article TheConversation.


Curious to find out more?Discover his background