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A $5M_{\odot }$ star has a much greater luminosity and exhausts central hydrogen in roughly $10^8$ to $2\times 10^8$ years, mainly through the CNO cycle. It crosses the Hertzsprung gap, develops shell hydrogen burning and ignites core helium without the strongly degenerate helium flash of the solar-mass case. Core helium burning lasts roughly $10^7$ years, with possible blue-loop evolution depending on the model.

It subsequently develops a carbon-oxygen core and double-shell burning on the Asymptotic giant branch, with thermal pulses, winds and envelope loss. For ordinary isolated evolution at this mass, the core does not reach sustained carbon ignition and the final remnant is a carbon-oxygen white dwarf. The broad boundary between white-dwarf and core-collapse outcomes depends on composition, overshooting, rotation and mass loss; the quoted mass is comfortably in the usual intermediate-mass regime.

An old globular cluster has lost its original massive main-sequence members. Its main-sequence turnoff lies near a low stellar mass, typically around $0.8M_{\odot }$ for an age of order $10^{10}$ years. The diagram shows a lower main sequence, a subgiant branch, a prominent red giant branch, a horizontal branch of core-helium-burning stars, an Asymptotic giant branch and a faint white dwarf cooling sequence. The preceding schematic labels these features. A few blue stragglers may lie above the old turnoff because interaction or merger rejuvenated them; they do not imply a young age for the bulk population.

After substantial envelope loss on the Asymptotic giant branch, a low- or intermediate-mass star's exposed core heats while its radius shrinks, often at approximately constant luminosity during continued shell burning. It may ionize the expelled envelope as a planetary nebula. After the remaining nuclear fuel is depleted, its luminosity decreases and it joins a white dwarf cooling track. Evolutionary tracks on the Hertzsprung-Russell diagram connect the central-star temperature and luminosity with core mass and elapsed time.