thirdbrightest
Thirdbrightest is a term used in astronomy and data analysis to denote the object that ranks third in brightness within a specified sample, field, or catalog. Brightness is usually expressed as apparent magnitude, a logarithmic scale where smaller numbers indicate brighter objects. The third-brightest object is the one with the third-lowest magnitude in the chosen dataset, and the label is dependent on the chosen wavelength band and observational conditions.
In practice, thirdbrightest is not a fixed celestial object; its identity can vary with the wavelength (for
Ranking considerations: Magnitude scales, photometric errors, and selection criteria influence ordering; variable stars can move in
See also: Brightest star, Apparent magnitude, Absolute magnitude, Photometry, Variable star, Astronomical catalogs.