Astrophysics (Index)About

infrared excess

(IRX, IR excess)
(more infrared than that of a star's typical spectrum)

An object's infrared excess (IRX) is additional infrared EMR beyond what is expected, e.g., that of a typical stellar spectrum or a black-body spectrum. An IRX is a sign of intervening matter contributing its own black body spectrum. In the case of a star, that could be something surrounding it such as a circumstellar disk (such as around a pre-main-sequence star) or circumstellar envelope (around an asymptotic giant branch star). IRX quantification is often carried out using a color index, e.g., comparing V with an infrared passband.

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