Description: In astronomy, the terms celestial body, celestial object, astronomical body, and astronomical object are used almost interchangeably as common terms for all the physical bodies and objects out there in space that astronomers study, including stars, planets, galaxies, gas clouds, and so on. Some astronomers use celestial or astronomical body in a narrower sense, namely for objects that are clearly separated from their environment – in that sense, a planet would be a celestial body, a gas cloud would not be (but it would still be an astronomical object). On the smallest scales, the terms are not commonly used. A proton might reach us from outer space, but would not be commonly referred to as an astronomical object, or a celestial body.

Related Terms:

• Asteroid
• Comet
• Galaxy
• Planet

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".