white dwarf
Explanation:
A appears on the chart at the point of low luminosity but high surface temperatures. This indicated a White Dwarf
A red giant is highly luminous stars mainly because of its large size. However, its surface temperature is hot a high when compared to white dwarfs. White dwarf surface temperatures can reach billions of degrees kelvin while red giants reach up to 5000 K on their surface.
A white dwarf is the last sequence of a low-mass star cycle and follows the red giant phase.
