Wiktionary
n. The brightness a star would have if not attenuated by distance or intervening gas or dust. As opposed to apparent brightness which it has as measured at a distance.
Wikipedia
Astronomers use the term intrinsic brightness to refer to how bright a star would be without the effects of distance or absorption due to interstellar dust or gas. While a bright distant star's apparent brightness might be less than a nearby dim star, due to the inverse square law for brightness, astronomers can discuss its intrinsic brightness meaning how bright the stars would be at a common distance. A star's intrinsic brightness is measured by its absolute magnitude.
Usage examples of "intrinsic brightness".
He made the acting pilot look up the intrinsic brightness of its sun and measure its apparent brightness from just off Dara.
The best way to measure the Hubble constant was by studying the most distant observable type la supernovae, which, like the Cepheids formerly studied in the same way, could all be assumed to have the same intrinsic brightness, so the dimmer they seemed, the farther they were.
Shapley had found a stellar standard candle, a star noticeable because of its variability, but which had always the same average intrinsic brightness.
By comparing the faintness of such stars when found in globular clusters with their real brightness, as determined from nearby representatives, Shapley could calculate how far away they are - just as, in a field, we can estimate the distance of a lantern of known intrinsic brightness from the feeble light that reaches us - essentially, the method of Huygens.
By timing a Cepheid's peaks, you could determine its intrinsic brightness, and therefore its distance.
If the stars were all the same intrinsic brightness, then some of them would have to be further away.
Get parallaxes so we can determine the location in space, transverse component of velocity, intrinsic brightness.