nanaxring.blogg.se

When he was 12, his family sent him to live with an aunt in Princeton so he could attend a top preparatory school.

His 264 papers were enormously influential in many areas of astronomy.īorn in 1877, the son of a Presbyterian minister, Russell showed early promise. In outward appearance, he was an old-fashioned product of the nineteenth century who wore high-top black shoes and high starched collars, and carried an umbrella every day of his life. He was nervous, active, competitive, critical, and very articulate he tended to dominate every meeting he attended. His memory was so phenomenal, he could correctly quote an enormous number of poems and limericks, the entire Bible, tables of mathematical functions, and almost anything he had learned about astronomy. His students later remembered him as a man whose thinking was three times faster than just about anybody else’s. When Henry Norris Russell graduated from Princeton University, his work had been so brilliant that the faculty decided to create a new level of honors degree beyond “summa cum laude” for him.

This investigation, and a similar independent study in 1911 by Danish astronomer Ejnar Hertzsprung, led to the extremely important discovery that the temperature and luminosity of stars are related (Figure 2). In 1913, American astronomer Henry Norris Russell plotted the luminosities of stars against their spectral classes (a way of denoting their surface temperatures). Or you might have a very tall, skinny fashion model with great height but relatively small weight, who would be found near the upper right.Ī similar diagram has been found extremely useful for understanding the lives of stars. You occasionally see a short human who is very overweight and would thus be more to the bottom left of our diagram than the average sequence of people. And, of course, there are some dramatic exceptions. It’s not mathematically exact-there is a wide range of variation-but it’s not a bad overall rule. Typically, if we have bigger bones, we have more flesh to fill out our larger frame. This makes sense if you are familiar with the structure of human beings. Generally speaking, taller human beings weigh more, whereas shorter ones weigh less. We can conclude from this graph that human height and weight are related. Most points fall along a sequence that goes from the upper left to the lower right. Notice that humans are not randomly distributed in the graph. In the way we have chosen to present our data, height increases upward, whereas weight increases to the left. Such a plot is shown in Figure 1 and it has some interesting features. For example, you might plot the heights of a large sample of humans against their weights (which is a measure of their mass). If you want to understand humans by comparing and contrasting their characteristics-without assuming any previous knowledge of these strange creatures-you could try to determine which characteristics lead you in a fruitful direction. To help understand what sorts of relationships might be found, let’s look briefly at a range of data about human beings. Most points lie along a “main sequence” representing most people, but there are a few exceptions. Height versus Weight: The plot of the heights and weights of a representative group of human beings. Measure the light curves and Doppler shifts for eclipsing binary stars.įigure 1. Measure the way a star’s light is blocked by the Moon.Ģ. Measure the period and radial velocity curves of spectroscopic binary stars.ġ. Measure the Doppler shift in the spectrum. Measure the apparent brightness and compensate for distance. Measure the spectrum and get the spectral type.ĭetermine which lines are present in the spectrum. When the characteristics of large numbers of stars were measured at the beginning of the twentieth century, astronomers were able to begin a deeper search for patterns and relationships in these data. We have also given an example of a relationship between two of these characteristics in the mass-luminosity relation. In this chapter and Analyzing Starlight, we described some of the characteristics by which we might classify stars and how those are measured. Discuss the physical properties of most stars found at different locations on the H–R diagram, such as radius, and for main sequence stars, mass.Identify the physical characteristics of stars that are used to create an H–R diagram, and describe how those characteristics vary among groups of stars.By the end of this section, you will be able to: