The reference must be corrected to calculate the distance at which stars are located
At the 217 meeting of the Astronomical Society of the United States, it has been proposed to correct the reference used for the calculation of cosmic distances in which one tries to define once and for all the kilogram. In fact, the Cefeid stars that astronomers use to calculate cosmic distances are closer than they expected.
They reached this conclusion when, through the NASA Spitzer Space Telescope, they discovered in the Delta Cephei star a gas nebula so far unknown. As nebulae absorb some of the light emitted by stars, Delta Cephei looks lower than it actually is and seems to be further away from what it is.
In addition to Delta Ceparte, 25% of the giant stars of the ampheid group have found nebulae through the Spitzer telescope. as a reference. Therefore, to calculate distances from them, scientists have first proposed to correct the effect of nebulae.