What kind of stars are found here?
A star in this region of the Hertzsprung-Russell diagram has a temperature of
roughly 16,000 kelvin (16,000 K), a luminosity 150 times less than that of the
Sun (0.007 × L), and a radius one hundred times smaller than the Sun
(R = 0.01 × R
).
This star lies along the narrow band in size, where white dwarf stars are
found.
Try to read the values of L, T, and R for yourself from the diagram. Do you estimate values for the luminosity, temperature, and size of the star similar to those listed above?
We can use the Stefan-Boltzmann Law to relate the temperature (T), size (R), and luminosity (L) of a star to each other. Measuring L, R, and T in solar units, we say that:
Let us say that the luminosity of the star is exactly 0.00676 times that of the Sun, and the radius is 0.0104 in solar units. We can use these values to find the temperature, in units of the temperature of the Sun.
This white dwarf is almost three times hotter than the Sun. Now, we can convert this value into kelvins, as we know that the Sun has a surface temperature of 5800 K.
We estimated a value of T = 16,000 K from the diagram, for stars found in this area – not bad work!