Glossary term: Main Sequence

Description: The main sequence is a long, thin grouping of stars on the Hertzsprung–Russell diagram. This sequence is home to stars in the main hydrogen fusion phase of their evolution. For all but the least massive stars, after a star has finished core hydrogen fusion it moves off the main sequence and begins to evolve into the giant phase. Stars on the main sequence are often referred to as dwarfs to differentiate them from giants. Hot stars on the main sequence are brighter than cool stars on the main sequence. The hottest stars fuse hydrogen quickly so often only spend a few million years on the main sequence. Stars like the Sun will spend around ten billion years on the main sequence with cooler stars maintaining stable hydrogen fusion for even longer.

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Term and definition status: This term and its definition have been approved by a research astronomer and a teacher

The OAE Multilingual Glossary is a project of the IAU Office of Astronomy for Education (OAE) in collaboration with the IAU Office of Astronomy Outreach (OAO). The terms and definitions were chosen, written and reviewed by a collective effort from the OAE, the OAE Centers and Nodes, the OAE National Astronomy Education Coordinators (NAECs) and other volunteers. You can find a full list of credits here. All glossary terms and their definitions are released under a Creative Commons CC BY-4.0 license and should be credited to "IAU OAE".