Distribution of very dense groups of stars in the Milky Way, called globular clusters, superimposed on a map of the Milky Way compiled from data obtained with the Gaia Space Observatory. Each dot represents a cluster of a few thousand to several million stars, as in the insert image of the Messier 10 cluster. The colour of the dots shows their metallicity, in other words, their abundance of heavy elements relative to the Sun. The C-19 stars are indicated by the light blue symbols. © N. Martin / Strasbourg Astronomical Observatory / CNRS; Canada-France-Hawaii Telescope / Coelum;
Distribution of very dense groups of stars in the Milky Way, called globular clusters, superimposed on a map of the Milky Way compiled from data obtained with the Gaia Space Observatory. Each dot represents a cluster of a few thousand to several million stars, as in the insert image of the Messier 10 cluster. The colour of the dots shows their metallicity, in other words, their abundance of heavy elements relative to the Sun. The C-19 stars are indicated by the light blue symbols. N. Martin / Strasbourg Astronomical Observatory / CNRS; Canada-France-Hawaii Telescope / Coelum; ESA / Gaia / DPAC - 98.5% of the Sun is made up of two light chemical elements, hydrogen and helium, while the remaining 1.5% consists of other heavier elements such as carbon, oxygen, and iron. The abundance of these heavier elements in a star is called its 'metallicity', and varies from star to star. It now turns out that our Galaxy is home to a stellar structure uniquely made of stars with extremely low metallicity, with a heavy element content 2,500 times lower than that of the Sun.
POUR LIRE CET ARTICLE, CRÉEZ VOTRE COMPTE
Et prolongez votre lecture, gratuitement et sans engagement.
Vos avantages
- Accès à l'ensemble du contenu
- Recevoir des alertes pour les nouvelles et les offres d'emploi
- Publier des annonces
