Is the Sun a low-mass star or a medium-mass star?

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xoxo1001
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In many text, the Sun is referred to as a low-mass star, yet it is also referred to as a medium-mass (or intermediate-mass) star in some other text. Which one is "correct"? What is the range of low-mass vs medium-mass? Is it really just low-mass vs high-mass and that medium-mass is just the upper limit of the low-mass portion?

For example, here (https://www.le.ac.uk/se/centres/sci/selfstudy/eab4.htm) says low-mass stars are "stars with masses less than half the mass of the Sun". If this is true, then the Sun is technically medium-mass. However, here (https://sites.uAlberta.ca/~pogosyan/teaching/ASTRO_122/lect17/lecture17.html) says low-mass stars are between 0.4 MSun to 4 MSun, which means that the Sun is considered as low-mass.

Confusing.
 

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PeroK
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Low-mass and medium-mass are relative terms, it seems.
 
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vela
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The description of a high-mass star on the first web page seems wrong to me. I'm no expert in astronomy, but I'm fairly certain that a 3-solar mass star is not going to end its life as a supernova.

How a star evolves depends primarily on its mass. A low-mass star will evolve in one way while a high-mass star will evolve in a markedly different way. Depending on the criteria you choose to divide up stellar evolution, you can get different descriptions of what kinds of star qualify low mass, intermediate mass, and high mass.

When I teach ASTR 101, we divide up stars into two classes: low mass stars that will end their lives as a white dwarf and high-mass stars that will ultimately die as a Type II supernova. The Sun would fall into the first class.
 
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sophiecentaur
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Which one is "correct"? What is the range of low-mass vs medium-mass?
With respect, who actually cares, except in a game of Top Trumps? The Sun is somewhere in between the very biggest and the very smallest stars. It is what it is and it does what it does and there is a load more of information about the Sun than about any others.
There are plenty of statistics around about millions / billions of stars that have been catalogued.
 
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sophiecentaur
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The Sun is somewhere in between the very biggest and the very smallest stars.
I could have been more helpful there. The Hertsprung Russel diagram gives a graph of characteristics of all (most) of the stars that we have observed. I chose this image because it shows dots where (some) stars have been measured.
hrdiagram_01.jpg

The Sun can be seen near the middle of that line of stars which follow 'normal' behaviour during their lifetimes. They spend most of the time somewhere on this Main Sequence line so ,when you observe a load of stars, most of them will sit somewhere on this line. There is a general rule which says Big Stars are brighter than small ones. So the big ones are top left and the small ones are bottom right for most of their lives.
 
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ohwilleke
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In many text, the Sun is referred to as a low-mass star, yet it is also referred to as a medium-mass (or intermediate-mass) star in some other text. Which one is "correct"?
Usually, when more than one definition is available, the choice of which definition makes the most sense depends upon why you want to know.
 
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sophiecentaur
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which definition makes the most sense depends upon why you want to know
Just like top Trumps :wink:. Even an Austin Seven can win.
 
  • #8
stefan r
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Red dwarfs are main sequence stars. They have convection all the way to the core.

Some stars have a radiative zone and convection in the upper layers.

Larger stars the radiative zone extends to the surface.

Some huge stars are fully convective.
 

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