Answer: d
If the star s mass when on the main sequence was below approximately 0.4 M ☉ it will never reach the central temperatures necessary to fuse helium. p. 169. It will therefore remain a hydrogen-fusing red giant until it runs out of hydrogen at which point it will become a helium white dwarf. § 4.1 6.1.
A neutron star is the collapsed core of a massive supergiant star which had a total mass of between 10 and 25 solar masses possibly more if the star was especially metal-rich. Neutron stars are the smallest and densest stellar objects excluding black holes and hypothetical white holes quark stars and strange stars. Neutron stars have a radius on the order of 10 kilometres (6.2 mi) and a …
A red dwarf is the smallest and coolest kind of star on the main sequence. Red dwarfs are by far the most common type of star in the Milky Way at least in the neighborhood of the Sun but because of their low luminosity individual red dwarfs cannot be easily observed.From Earth not one star that fits the stricter definitions of a red dwarf is visible to the naked eye.
When the progenitor star is below about 20 M ☉ – depending on the strength of the explosion and the amount of material that falls back – the degenerate remnant of a core collapse is a neutron star . Above this mass the remnant collapses to form a black hole. The theoretical limiting mass for this type of core collapse scenario is about 40–50 M ☉.
The asymptotic giant branch (AGB) is a region of the Hertzsprung–Russell diagram populated by evolved cool luminous stars.This is a period of stellar evolution undertaken by all low- to intermediate-mass stars (0.6–10 solar masses) late in their lives.. Observationally an asymptotic-giant-branch star will appear as a bright red giant with a l…