Yellow stars with low strength hydrogen lines. This type includes the modern "G" and "K" types and the old "F" type, and among the stars of this type: the sun and arthropods.
If a star has a large luminosity and a low surface temperature, it must have a large surface area to compensate for the low temperature and still emit a high amount of energy. This would make the star a red supergiant, a type of star that is both luminous and cool at the same time.
A blue dwarf star would have high temperature and low luminosity in the Hertzsprung-Russell (HR) diagram. Blue dwarf stars are in the lower left corner of the diagram, characterized by their high surface temperature and faint luminosity compared to other stars of similar temperature.
it is a very large star of high luminosity and low surface temperature.....=)))))
Betelgeuse, a cool distant supergiant star, has a high luminosity primarily due to its large size and surface area. Despite its relatively low temperature, its vast volume allows it to emit a significant amount of energy. The combination of its expansive radius and the Stefan-Boltzmann Law, which states that a star's luminosity increases with the fourth power of its temperature, results in Betelgeuse's impressive brightness. Thus, even with a lower temperature, its sheer size compensates, leading to high luminosity.
White dwarfs.
White dwarfs.
The luminosity of a star is related to its surface temperature and size. Hotter stars with larger surface areas tend to have higher luminosities, while cooler stars with smaller surface areas have lower luminosities.
There are 2 main factors: the size of the star and its surface temperature. A larger size means a larger surface area to emit light. A higher surface temperature increases the energy emitted. Seen from Earth, the brightness of a star depends on how far away the star is as well as its actual luminosity.
The luminosity of a star is closely related to its size, with larger stars generally being more luminous than smaller ones. This relationship is partly explained by the star's surface area and temperature; a larger star has a greater surface area to radiate energy and often has a higher temperature, both of which contribute to increased luminosity. According to the Stefan-Boltzmann law, a star's luminosity is proportional to the fourth power of its temperature and the square of its radius, highlighting the significant impact of size on a star's brightness.
The surface temperature of the star Gamma Pyxidis, a B-type main-sequence star, is approximately 20,000 to 25,000 Kelvin. This high temperature gives it a blue hue and contributes to its classification as a hot star. Its significant temperature also results in a substantial luminosity, making it one of the brighter stars in its region.
The relationship between a star's temperature and luminosity is described by the Stefan-Boltzmann Law, which states that a star's luminosity (total energy output) is proportional to the fourth power of its surface temperature (in Kelvin) multiplied by its surface area. This means that as a star's temperature increases, its luminosity increases significantly, assuming other factors like size remain constant. Additionally, hotter stars tend to be larger and more luminous than cooler stars, which further emphasizes the interconnectedness of temperature and luminosity in stellar properties.
A star with a surface temperature of approximately 9000 K and a luminosity between 1 to 20 times that of the Sun is likely a type A main-sequence star. These stars are known for their blue-white color and burn hydrogen in their cores. An example of such a star is Alpha Centauri A, which exhibits characteristics consistent with this temperature and luminosity range.