Stars begin their life on the main sequence, but then evolve off into red giant phase and supergiant phase before dying as white dwarfs or some more violent endpoint. The HR Diagram for the brightest stars in the LMC and SMC from [5]. Thermonuclear Fusion: Energy generation is the heart of stars. If you look on the Australian Telescope National facility website, their HR diagram shows this clearly.

The Red Giant interior is typically a Carbon/Oxygen core blowing material out into space and then collapsing into a White Dwarf. What needs to be remembered here is that a huge envelope of non-burning Hydrogen and other blown out dust and gases are surrounding the outermost layer of Hydrogen burning. The resulting diagram was named after the two discovering astronomers, Ejnar Hertzsprung of Denmark and Henry Norris Russell of America. It is the larger star at the end of the handle of the Little Dipper (Ursa Minor). This diagram is a plot of luminosity (absolute magnitude) against the colour of the stars ranging from the high-temperature blue-white stars on the left side of the diagram to the low temperature red stars on the right side. While Red Giants and Red Supergiants may appear to be similar, their interior structures are greatly different. Look up blue supergiant star in Wiktionary, ... HR diagram or HRD, is a scatter plot of stars showing the relationship between the stars' absolute magnitudes or luminosities versus their stellar classifications or effective temperatures. Return to STARS. The HR diagram is a key tool in tracing the evolution of stars.

Above 8-10 solar masses, the evolutionary tracks of the HR Diagram lead into the domains of the blue and red supergiants.

We argue that it is now in a phase of evolution that is analogous to that of degenerate core giants evolving through the proto-planetary nebula phase, but at a much higher luminosity. Formation; Properties; Examples; References; Blue supergiants (BSGs) are found towards the top left of the Hertzsprung–Russell diagram to the right of the main sequence. This index comes from a difference in the amount of blue light a star emits and the amount of visual (more green) light emitted and is related to the temperature.

Alcyone, a typical blue giant. Look at the chart below and you will see that our Sun is a medium yellow star. THE HERTZSPRUNG-RUSSELL (HR) DIAGRAM And Its Variable Stars Jim Kaler The HR Diagram is linked to The Natures of the Stars and to Spectra. We argue that it is now in a phase of evolution that is analogous to that of degenerate core giants evolving through the proto-planetary nebula phase, but at a … Most stars lie on the main sequence, which extends diagonally across the H–R diagram from high temperature and high luminosity to low temperature and low luminosity. Back to Astronomy home page. IRC +10420 may be evolving from a red supergiant to the blue side of the H-R diagram, perhaps to become a Wolf-Rayet star. Astronomers still differ over whether to classify at least one of the stars as a supergiant, based on subtle differences in the spectral lines. Stars found in the blue giant region of the HR diagram can be in very different stages of their lives, but all are evolved stars that have largely exhausted their core hydrogen supplies. During these evolutionary steps, the star moves back and forth across the HR Diagram (seen above), becoming Blue Supergiants again, then Red Supergiants. Understanding the H-R Diagram Lesson and Assignment Understanding the H-R Diagram Lesson and Assignment Introduction: Stars are classified according to their brightness and temperature. Evolution. LMC stars are closed symbols and those in the SMC are shown as open symbols. They are larger than the Sun but smaller than a red supergiant, with surface temperatures of 10,000–50,000 K and luminosities from about 10,000 to a million times the Sun. The stellar astronomer's greatest tool is the HR diagram and its variants. Understanding the H-R Diagram Lesson and Assignment At its brightest, Polairs is about 6,000 to 10,000 times brighter than our Sun.

IRC +10420 may be evolving from a red supergiant to the blue side of the H-R diagram, perhaps to become a Wolf-Rayet star. Here is an HR Diagram of all 15 of the brightest stars in the sky visible in the United States, as well as other interesting stars.