Assuming that the exponent n in the mass–luminosity relation is 3.5, show that the mass of Khad is about 17 solar masses.

Outline the likely evolution of the star Khad after it leaves the main sequence.

$\frac{{{L_{\rm{K}}}}}{{{L_{\rm{S}}}}} = {\left[ {\frac{{{m_{\rm{K}}}}}{{{m_{\rm{S}}}}}} \right]^{3.5}}$;
$m = {\left[ {\frac{{{L_{\rm{K}}}}}{{{L_{\rm{S}}}}} \times {m_{\rm{S}}}^{3.5}} \right]^{\frac{1}{{3.5}}}} = {\left[ {2.0 \times {{10}^4}} \right]^{\frac{1}{{3.5}}}}{m_{\rm{S}}}{\rm{ = 16.9}}{{\rm{m}}_{\rm{S}}}$;
hence m_K≈17m_S

Khad will become a red supergiant/superred/superred giant;
a supernova will take place;
the core/remnant will form a neutron star or black hole;