The globular cluster 2MASS-GC02 is not visible the visible portion of the electromagnetic spectrum, due to interstellar extinction, but was spotted in infrared light.
22.
A comparison of this value with the apparent magnitude allows the approximate distance to be determined, after correcting for interstellar extinction of the luminosity because of gas and dust.
23.
In 1971, HR 5171A was identified as a G8 hypergiant, reddened by over 3 magnitudes of interstellar extinction and also by half a magnitude of extinction from circumstellar material.
24.
Thus a fair measure of its absolute magnitude can be determined without knowing its distance nor the interstellar extinction, allowing astronomers to estimate a star's distance and extinction without parallax calculations.
25.
Wray 17-96 has an absolute bolometric magnitude of & minus; 10.9 ( 1.8 million solar units ), making it one of the interstellar extinction and the visual brightness is reduced by nearly 9 magnitudes.
26.
Measurements in different eras are not always calibrated to the same spectral bands, and the values have to be de-reddened to account for interstellar extinction, but the small change corresponds to records of the spectrum and are considered to be real.
27.
By analysing the interstellar extinction between Earth and the system, G�ver and colleagues calculated the most likely distance to be 5.8 kpc ( 19, 000 light-years ), and the neutron star's mass to be 1.74 ?0.14 times that of the Sun and radius to be a mere 9.3 ?1.0 km.
28.
Interstellar extinction the dimming effects of dust and gas in space between it and us " or " to Atmospheric extinction which itself can mean either the dimming by absorbtion of our atmosphere in general, or the extra atmospheric dimming / absorbtion caused by the star being closer to the horizon than the zenith ( since then we're looking at it through more atmosphere than if it were at the zenith ).
