The Laws That Determine How Dust Affects The Light That Reaches Us From The Stars Are Being Rewritten
If the space traversed by light to reach our eyes were empty, knowing the properties of a star could be as simple as taking a picture of it and measuring its glow (something known as photometry). But the interstellar environment is strewn with dust that absorbs and scatters light, making objects look less luminous and redder—or colder—than they actually are. A recently published paper makes it possible, at last, to correct this distorting effect adequately.
“In the range of wavelengths that our eyes perceive -the visible light- of every billion photons that a star in the centre of the Milky Way emits, only one reaches our eyes,” says Jesús Maíz Apellániz, researcher at the Institute of Astrophysics of Andalusia (IAA-CSIC) in charge of the publication. “This is an extreme example of how dust affects the light of stars, a phenomenon that takes place in every single environment, albeit with less intensity.”
The effect of dust, then, must be reckoned with in any astronomical observation before trying to extract the characteristics of an object. Maíz Apellániz, together with an international team of collaborators, showed that the laws used since 1989 to calculate the extinction of light produced by dust had serious limitations and yielded, among others, erroneous temperature estimates for stars. So they took it upon themselves to change those laws.