The resulting
color-magnitude diagrams enabled Carraro to classify the stars into low-mass dwarfs still on the hydrogen-burning main sequence and higher-mass stars that had evolved to the red-giant stage or beyond.
Especially important are binaries in the Hyades, whose
color-magnitude diagram is a standard for calibrating interstellar distance scales.
This value is plotted against the star's visual brightness to produce a color-magnitude diagram. This is one type of the more general Hertzsprung-Russell (H-R) diagram that is so crucial to our understanding of stellar evolution.
The color-magnitude diagram for a cluster usually shows stars lined up along the main sequence in the lower-right portion of the diagram.
With our highly uncertain TRGB (tip of the red-giant branch) distance (due to scarcity of stars) and the similarity between the two CMDs (
color-magnitude diagrams), this introduces the possibility that d1005+68 is a satellite of BK5N," the team wrote.
Beyond that point, chapter by chapter, he leapfrogs his prehistoric report by orders of magnitude of years, tackling potassium-argon dating and the ages of fossil hominids, molecular dating and divergence times for mammalian lineages, meteorites and the age of the solar system, and the use of
color-magnitude diagrams for assessing ages of collections of stars.
For a selection of 20-50 nearby late-type and apparently "single" close binaries, images in B, R filters will be taken at the 0.9m telescope and suitable teriary candidates will be identified on
color-magnitude diagrams. These candidates were missed previously because old visual catalogues are incomplete beyond 10-th magnitude.
For instance, we can construct infrared color-magnitude diagrams that share many features of their visible-light counterpart, the Hertzsprung-Russell (H-R) diagram.
The infrared color-magnitude diagrams at right compare stars in a random part of the Milky Way with stars in the Large Magellanic Cloud.
Today's amateurs can create
color-magnitude diagrams and estimate the age of open star clusters by determining the turnoff point of the main-sequence stars.
Color-magnitude diagrams also confirm that the brightest, hottest stars in any born-together group are the first to consume their innermost reserves of nuclear fuel.