Their topics include fundamentals of stellar variability observations, stellar structure and evolution theory, stellar pulsation theory, Cepheid and related variable stars, pulsating stars close to the lower main sequence in the H-R diagram
, hot subdwarf pulsators, and pulsating degenerate stars.
In its usual form established by Russell, the H-R diagram is a graph showing the relation of stellar luminosities on the vertical axis and temperatures on the horizontal axis, with the brighter stars near the top and the hotter stars on the left.
Thus the H-R diagram is also called the color-magnitude diagram.
A PhD-level science educator/co-editor of a series that provides systematic overviews of the latest ideas on the nature and evolution of major celestial objects covers the properties and types of stars in the context of the H-R Diagram
(for inferring information about a star's life stage by measuring its temperature and luminosity), and the large systems of stars known as galaxies.
Simply written in expository prose, "The Lives of Stars" has chapters that define how a star is born, the H-R diagram
(a way of measuring the intensity of stars that reveals the star's projected life story), descriptions of many different types of stars, star clusters, the origin of the elements, and what to considre about the possibility of life in space, to name just a few.
Giving Hertz-sprung credit for priority, it is usually called the Hertzsprung-Russell diagram, or the H-R diagram
The most difficult part in constructing an H-R diagram is measuring each star's luminosity.
White dwarfs are far from red giants on the H-R diagram.
As a humanist, I was fascinated that the H-R diagram could serve as a metaphor for human lives as well.
As the H-R diagram predicts, her next stage will be that of a faded white dwarf, joining the diminished, white-haired folks at her home, who, having spent all their fuel, barely talk or move.
Bodies migrate in characteristic ways across the H-R diagram
The backbone of the H-R diagram
is the main sequence (see the illustration at left).