Final answer:
A star in the lower left corner of an H-R diagram is most likely a white dwarf, characterized by high temperature and low luminosity due to its small surface area.
Step-by-step explanation:
A star located in the lower left corner of an H-R (Hertzsprung-Russell) diagram is most likely a white dwarf. This region of the H-R diagram represents stars that have both high temperature and low luminosity. The reason for a star being dim despite its high temperature is that it has a very small surface area, characteristic of white dwarfs. White dwarfs are the remnants of stars like the Sun that have exhausted their nuclear fuel and shed their outer layers, leaving behind a hot, dense core.
Main sequence stars, red giants, and supergiants are found in different regions of the H-R diagram. For example, main sequence stars form a narrow band from the upper left to the lower right of the H-R diagram, red giants are found in the upper right corner indicating cool and bright stars, and supergiants are also very bright but can have a range of temperatures.
Therefore, in an H-R diagram, the stars such as cool supergiants, white dwarfs, the Sun, and main-sequence stars are all positioned in specific regions according to their luminosities and surface temperatures, showcasing the various stages of stellar evolution.