e. there is a minimum temperature for hydrogen fusion.
They are both hotter and cooler because the main sequence contains a lot of stars including the Sun. The main sequence is a region on a Hertzsprung-Russell diagram which plots stars on a graph of brightness against surface temperature. Each star is a point on the diagram because it has one value of brightness and one of temperature. All the main-sequence stars lie on or near a line drawn from top left to lower right. The Sun is about halfway along the main sequence.
The main sequence is a map of star brightness against their temperature. Stars that lie on the main sequence in the top left are the high mass stars. Cooler, smaller stars lie near the line at the lower right.
Most stars are plotted along the main sequence in the Hertzsprung-Russell (HR) diagram, which extends diagonally from the upper left (hot and luminous stars) to the lower right (cool and less luminous stars). This is because the majority of stars, including our Sun, spend the majority of their lives in the main sequence phase where they are fusing hydrogen into helium.
Depending on how "low" on the chart it will either be a red dwarf or a PMS (Pre-main sequence) star.
The term "main sequence" refers to stars that are in the phase of their life cycle where they are fusing hydrogen into helium in their cores. It is called the main sequence because the majority of a star's life is spent in this phase, during which it maintains a stable energy output and size.
The reason main sequence has a limit at the lower end is because of temperature and pressure. The lower limit exists in order to exclude stellar objects that are not able to sustain hydrogen fusion.
They are both hotter and cooler because the main sequence contains a lot of stars including the Sun. The main sequence is a region on a Hertzsprung-Russell diagram which plots stars on a graph of brightness against surface temperature. Each star is a point on the diagram because it has one value of brightness and one of temperature. All the main-sequence stars lie on or near a line drawn from top left to lower right. The Sun is about halfway along the main sequence.
Because, giants can only occur once they leave the main sequence.
The main sequence is a map of star brightness against their temperature. Stars that lie on the main sequence in the top left are the high mass stars. Cooler, smaller stars lie near the line at the lower right.
Because there not that hot
Stars don't "lose" their "main sequence", because it's not something a star can "have" in the first place.Stars are more properly described as being "on" or "off" the "main sequence", and "sequence" isn't a good word for it anyway, because it implies that there is an actual sequence of events involved; in fact, the normal life sequence of a star has it going off the main "sequence".It may help if you stop thinking of them as "main sequence" stars and start thinking of them as either dwarfs or type III stars.
The lower right part of the main sequence in the Hertzsprung-Russell diagram contains the stars that took the longest to reach the main sequence. These stars are low mass and cool, so they undergo a longer contraction phase before they start fusing hydrogen in their cores and settle onto the main sequence.
The Sun is a medium mass star on the main sequence.
Most stars are plotted along the main sequence in the Hertzsprung-Russell (HR) diagram, which extends diagonally from the upper left (hot and luminous stars) to the lower right (cool and less luminous stars). This is because the majority of stars, including our Sun, spend the majority of their lives in the main sequence phase where they are fusing hydrogen into helium.
Depending on how "low" on the chart it will either be a red dwarf or a PMS (Pre-main sequence) star.
The main sequence on the Hertzsprung-Russell diagram represents the stage in a star's life when it is undergoing nuclear fusion of hydrogen into helium in its core. Stars spend the majority of their lifetime on the main sequence, where they maintain a stable balance between inward gravitational pressure and outward radiation pressure. The main sequence runs diagonally from high temperature, high luminosity stars (top left) to lower temperature, lower luminosity stars (bottom right).
The term "main sequence" refers to stars that are in the phase of their life cycle where they are fusing hydrogen into helium in their cores. It is called the main sequence because the majority of a star's life is spent in this phase, during which it maintains a stable energy output and size.