Encyclopedia of Astrobiology

Living Edition
| Editors: Muriel Gargaud, William M. Irvine, Ricardo Amils, Henderson James Cleaves, Daniele Pinti, José Cernicharo Quintanilla, Michel Viso

Emissivity

Living reference work entry
DOI: https://doi.org/10.1007/978-3-642-27833-4_506-2

Definition

Emissivity is a quantity in physics that depends on wavelength and that characterizes the efficiency with which a surface radiates, compared to a black body at the same temperature. A black surface has an emissivity close to 1 and a polished reflecting surface an emissivity close to 0. Because of Kirchhoff’s law, the same quantity characterizes also the ability of a surface to absorb or to reflect impinging radiation (absorptivity = emissivity, albedo = 1 − emissivity). Emissivity is a positive, dimensionless quantity, lower than or equal to 1.

See Also

Keywords

Bioorganic Chemistry Dimensionless Quantity Black Body Black Surface 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  1. 1.LESIAObservatoire Paris-Site de MeudonMeudonFrance