<h1>35-320 billion years</h1>
<p>Using this <a href="http://hyperphysics.phy-astr.gsu.edu/hbase/Astro/startime.html" rel="nofollow noreferrer">website</a>. I can calculate the lifetime of the stars that you asked for.</p>
<p>A 0.25 M<sub>☉</sub> red dwarf lives for around 350 billion years, while a 0.6 M<sub>☉</sub> red dwarf lives for  35 billion years.</p>
<p>And also using the same calculator, I get the lifespan of TOI-700, with a mass of 0.41 M<sub>☉</sub>, as 92.905 billion years.</p>
<p>The equation to calculate stellar lifespan, in case you need it, is given below:-
<a href="https://i.sstatic.net/Oa5O2.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/Oa5O2.png" alt="Stellar lifespan equation" /></a></p>
<p>Where T= Stellar Lifespan, M= Mass of star, and M<sub>☉</sub>= Mass of Sun.</p>

CC BY-SA 4.0
2023-02-03T17:34:09.117Z
Whilst a reasonable starting approximation for solar-type stars and more massive, that formula doesn't take account of the fact that (i) $L$ is not proportional to $M^{3.5}$ for lower-mass stars and (ii) the fraction of the mass that can "burn" approaches 100% as the stellar mass falls to 0.35 solar masses and is much larger than the ~20% of mass that is available to burn in a solar mass star.  Both of these effects increase the lifetime over the estimates based on that equation. However, I don't know of any published models that would help.
ProfRob
CC BY-SA 4.0
2023-02-03T15:31:47.847Z
2023-02-03T15:31:47.847Z
Arcturus
<p>Wikipedia and the reference paper they are using offer some insights into the lifespan of smaller red dwarf stars (<a href="https://en.wikipedia.org/wiki/Red_dwarf#/media/File:Red_dwarf_lifetime.png" rel="nofollow noreferrer">link</a>). However it offers no insight as to what the projected lifespan of larger red dwarf stars is, i.e. red dwarfs between 0.25 and 0.6 solar masses. How are long are red dwarf stars such as TOI-700 which is 0.41 solar masses project to life?</p>

<stellar-evolution><red-dwarf>
Lifespan of higher mass red dwarf stars
user1628056
# Lifespan of higher mass red dwarf stars

(Asked by: username_0 on 2023-02-03)

Wikipedia and the reference paper they are using offer some insights into the lifespan of smaller red dwarf stars ([link](https://en.wikipedia.org/wiki/Red_dwarf#/media/File:Red_dwarf_lifetime.png)). However it offers no insight as to what the projected lifespan of larger red dwarf stars is, i.e. red dwarfs between 0.25 and 0.6 solar masses. How are long are red dwarf stars such as TOI-700 which is 0.41 solar masses project to life?

**Tags:** stellar-evolution, red-dwarf

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## 1 answers

### Answer by username_1 on 2023-02-03. Score: 3

# 35-320 billion years

Using this [website](http://hyperphysics.phy-astr.gsu.edu/hbase/Astro/startime.html). I can calculate the lifetime of the stars that you asked for.

A 0.25 M☉ red dwarf lives for around 350 billion years, while a 0.6 M☉ red dwarf lives for 35 billion years.

And also using the same calculator, I get the lifespan of TOI-700, with a mass of 0.41 M☉, as 92.905 billion years.

The equation to calculate stellar lifespan, in case you need it, is given below:-
[![Stellar lifespan equation](https://i.sstatic.net/Oa5O2.png)](https://i.sstatic.net/Oa5O2.png)

Where T= Stellar Lifespan, M= Mass of star, and M☉= Mass of Sun.

> **Comments:**
> **username_2**: Whilst a reasonable starting approximation for solar-type stars and more massive, that formula doesn't take account of the fact that (i) $L$ is not proportional to $M^{3.5}$ for lower-mass stars and (ii) the fraction of the mass that can "burn" approaches 100% as the stellar mass falls to 0.35 solar masses and is much larger than the ~20% of mass that is available to burn in a solar mass star.  Both of these effects increase the lifetime over the estimates based on that equation. However, I don't know of any published models that would help.  

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