The light reaching the Earth from the star alpha Centauri $(4\mathrm{.}3$ light years away$)$

took $8\mathrm{.}6$ years to travel here

was Doppler shifted by a factor of $8\mathrm{.}6$

was Doppler shifted by a factor of $4\mathrm{.}3$

took $4\mathrm{.}3$ years to travel here

did not reach the Earth yet