<p>The Sun's current mass loss rate - a combination of the solar wind and radiation from the Sun - amounts to something like <span class="math-container">$10^{-13}$</span> solar masses per year.</p>
<p>The mass loss rates from red giant stars are variable, but much larger, and dominated by wind losses, rather than radiation. A common parameterisation of the average mass loss rate is the Reimers mass-loss rate (or variants thereof, e.g. <a href="https://arxiv.org/abs/astro-ph/0507598#" rel="noreferrer">Schroeder &amp; Cuntz 2005</a>)
<span class="math-container">$$ \dot{M} = -\eta \frac{L R}{M}\ (M_\odot /{\rm year})$$</span>
where <span class="math-container">$L$</span>, <span class="math-container">$R$</span> and <span class="math-container">$M$</span> are the luminosity, radius and mass of the red giant in solar units and <span class="math-container">$\eta$</span> is a fitting parameter that must be determined empirically and is about <span class="math-container">$4\times 10^{-13}$</span> in this unit system.</p>
<p>For a typical red giant with <span class="math-container">$M=2M_\odot$</span>, <span class="math-container">$L=1000 L_\odot$</span> and <span class="math-container">$R=100R_\odot$</span>, the Reimers formula gives <span class="math-container">$2\times 10^{-8}$</span> solar masses per year. However, for the very biggest giants and during pulsational mass loss during the AGB phase, mass loss rates could reach <span class="math-container">$10^{-6}$</span> solar masses per year or more.</p>
<p><strong>An aside</strong></p>
<p>Since a star spends a few per cent of its life as a big red giant, but has 5-6 orders of magnitude bigger mass-loss rate during this time, you can easily see that most mass loss occurs when the star is a red giant.</p>

CC BY-SA 4.0
2021-11-04T07:12:13.460Z
2021-11-04T07:27:56.790Z
2021-11-04T07:27:56.790Z
ProfRob
<p>Do red giant stars produce more stellar wind than
when they were ordinary yellow stars?  If so, how big a difference are we talking about?</p>

CC BY-SA 4.0
2021-11-03T17:46:20.240Z
Yes. Many orders of magnitude more.
ProfRob
CC BY-SA 4.0
2021-11-03T18:43:41.040Z
@constantthin What do you think? What research have you done to answer your own question?
Daddy Kropotkin
CC BY-SA 4.0
2021-11-06T22:51:56.130Z
The close vote for "This question currently includes multiple questions in one" doesn't make sense to me.
uhoh
<solar-wind><red-giant>
Does a red giant star produce more stellar wind than a yellow star?
Constantthin
# Does a red giant star produce more stellar wind than a yellow star?

(Asked by: username_0 on 2021-11-03)

Do red giant stars produce more stellar wind than
when they were ordinary yellow stars? If so, how big a difference are we talking about?

**Tags:** solar-wind, red-giant
> **Comments:**
> **username_1**: Yes. Many orders of magnitude more.  
> **username_2**: @constantthin What do you think? What research have you done to answer your own question?  
> **username_3**: The close vote for "This question currently includes multiple questions in one" doesn't make sense to me.  

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## 1 answers

### Answer by username_1 on 2021-11-04. Score: 5

The Sun's current mass loss rate - a combination of the solar wind and radiation from the Sun - amounts to something like $10^{-13}$ solar masses per year.

The mass loss rates from red giant stars are variable, but much larger, and dominated by wind losses, rather than radiation. A common parameterisation of the average mass loss rate is the Reimers mass-loss rate (or variants thereof, e.g. [Schroeder & Cuntz 2005](https://arxiv.org/abs/astro-ph/0507598#))
$$ \dot{M} = -\eta \frac{L R}{M}\ (M\_\odot /{\rm year})$$
where $L$, $R$ and $M$ are the luminosity, radius and mass of the red giant in solar units and $\eta$ is a fitting parameter that must be determined empirically and is about $4\times 10^{-13}$ in this unit system.

For a typical red giant with $M=2M\_\odot$, $L=1000 L\_\odot$ and $R=100R\_\odot$, the Reimers formula gives $2\times 10^{-8}$ solar masses per year. However, for the very biggest giants and during pulsational mass loss during the AGB phase, mass loss rates could reach $10^{-6}$ solar masses per year or more.

**An aside**

Since a star spends a few per cent of its life as a big red giant, but has 5-6 orders of magnitude bigger mass-loss rate during this time, you can easily see that most mass loss occurs when the star is a red giant.


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