Glossary term: Red Giant

Also known as M giant

Description: A red giant is a star that was originally a dwarf star like the Sun, which has run out of hydrogen fuel, and expanded as it changes to helium or heavier elements for fuel. It is typically 100 or more times larger and more powerful than the Sun, so life on Earth will not survive when the Sun reaches this late stage of stellar evolution, billions of years from now. Examples of red giants are Arcturus, in Bootes, and Mira, in Cetus. Red giants are unstable to pulsation (in-and-out vibration) and can vary in brightness by a factor of 1000, as Mira does.

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Term and definition status: This term and its definition is still awaiting approval

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".