| | The Astrophysics Spectator: LTE Radiation (Site not responding. Last check: ) |
 | | An atmosphere is said to be in local thermal equilibrium, often abbreviated as LTE in the astronomy literature, when at each point the electrons and ions are described by a thermal energy distribution, but the temperature of that distribution varies from point to point. |
 | | Radiation that passes through such an atmosphere attempts to come into thermal equilibrium with the plasma as it flows through the photosphere into space. |
 | | For a hot radiation field passing through a cooler atmosphere, which characterizes most of the emission through the atmosphere of a star, this interaction produces absorption lines, which are dips in the continuum spectrum. |
| www.astrophysicsspectator.com /topics/radiation/LTE.html (958 words) |