Maybe Not. Iâve been talking about the death of the total cholesterol paradigm for ten years, and now the research is so strong that itâs time to send flowers. The total cholesterol, with its âgoodâ (HDL) and âbadâ (LDL) cholesterol paradigm, is dead. Taking its place is a new model of vascular biology, epigenomics, and nutragenomicsâhow foods (and supplements) influence heart health.
delta Cephei. The namesake star in the very important class of stars known as Cepheid variables, this star formed part of the original study in which Henrietta Leavitt first discovered that the periods of luminosity were related to their absolute luminosity.This has proved to be an important distance measuring tool.amed after delta-Cephei, Cepheid Variables are the most important type of variable because it has been discovered that their periods of variability are related to their absolute luminosity.
Once the period of a distant Cepheid has been measured, its luminosity can be determined from the known behavior of Cepheid variables. Then its absolute magnitude and apparent magnitude can be related by the distance modulus equation, and its distance can be determined.Cepheid variables can be used to measure distances from about 1kpc to 50 Mpc. For example, if an astronomer observed a Cepheid star with period of 34 days, comparing to previously measured Cepheids, its absolute magnitude is -5.65. If its apparent magnitude was +23.0, the astronomer could use the distance modulus equation: m - M = 5 log d - 5.