Glossary term: Photosphere
Description: The photosphere ("light sphere") is the layer of a star from which the light that we observe emerges. Light emitted from deeper, denser layers will be absorbed before it can escape from the star. Higher layers are less dense, and do not emit significant light.
Related Terms:
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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".
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In Other Languages
- Arabic: الغلاف الضوئي
- German: Photosphäre
- French: Photosphère
- Italian: Fotosfera
- Japanese: 光球 (external link)
- Korean: 광구
- Simplified Chinese: 光球
- Traditional Chinese: 光球
Related Media
High-resolution image of the surface of the Sun
Caption: This high-resolution image of a small portion of the outermost visible "surface" of the Sun (the photosphere) covers an area 36,500 by 36,500 km. It was one of the first images taken by the Daniel K. Inouye Solar Telescope, as part of the telescope's Science Verification Phase. Each of the cells that are visible is about the size of the US state Texas, or of France, or of Afghanistan, or of Somalia. In the brighter centers of these cells, plasma from the underlying regions rises to the surface, cools off, and then sinks down again at the location of the darker lanes delineating the cells. In these dark lanes we can also see the tiny, bright markers of magnetic fields.
Credit: NSO/NSF/AURA
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License: CC-BY-4.0 Creative Commons Attribution 4.0 International (CC BY 4.0) icons
Close-up view of a sunspot
Caption: This image of a sunspot was taken by the Daniel K Inouye Solar Telescope (DKIST), operated by the U.S. National Science Foundation. It was taken only in light with a wavelength of 530 nanometers, within the greenish-yellow part of the visible spectrum.
The picture reveals the detail of the spot's structure and the Sun’s photosphere. The dark central region, known as the umbra, is surrounded by a lighter area called the penumbra with radially elongated features stretching towards the umbra. Note that the umbra and penumbra here are not the same as the umbra and penumbra that occur during an eclipse.
The sunspot measures approximately 5000 kilometres in diameter, roughly equivalent to the east-west span of China. While the umbra appears black, it is actually hot and bright. It only appears dark because it is a few thousand kelvin cooler than the surrounding solar photosphere. Surrounding the sunspot, granulation patterns of plasma are visible on the photospheric surface of the Sun.
Credit: NSO/NSF/AURA
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License: CC-BY-4.0 Creative Commons Attribution 4.0 International (CC BY 4.0) icons
