Life cycle of stars Q. What color are the hottest stars? What color are the coolest stars? Topic: Life cycle of stars Q. What color are the hottest stars? What color are the coolest stars?
The Correct Answer and Explanation is:
Answer:
The hottest stars are blue in color, while the coolest stars are red.
Explanation
The color of a star is directly related to its surface temperature, which is a key characteristic in the life cycle of stars. This color-temperature relationship is governed by blackbody radiation, where hotter objects emit more light at shorter (bluer) wavelengths, and cooler objects emit more light at longer (redder) wavelengths.
Stars are categorized using the spectral classification system, which orders stars by their surface temperature and color: O, B, A, F, G, K, M — from hottest to coolest.
- O-type stars are the hottest, with surface temperatures above 30,000 K, and they appear blue or blue-white.
- M-type stars are the coolest, with temperatures below 3,500 K, and they appear red.
This temperature difference is due to the processes happening within the stars. Hot blue stars are usually young and very massive, burning through their nuclear fuel (hydrogen) at a much faster rate. Because of their high mass and brightness, they live shorter lives—often just a few million years. These stars can end their lives in dramatic explosions such as supernovae, often leaving behind neutron stars or black holes.
On the other hand, cool red stars, like red dwarfs, are typically small and burn fuel slowly. This slow burning makes them incredibly long-lived, sometimes lasting for trillions of years, far longer than the current age of the universe. Despite being cooler and dimmer, red dwarfs are the most common type of star in the Milky Way galaxy.
Understanding star color and temperature helps astronomers determine a star’s age, size, and stage in its life cycle—important for studying the formation and evolution of galaxies and the universe as a whole.
