<p>I suppose, there must be some set of evolved early-type low-metallicity K-dwarfs that are going through or entering subgiant phase nowadays.</p>
<p>In theory, even early-type M-dwarfs with initial mass &gt; 0.3 Msol can produce some kind of &quot;small red giants&quot;, leaving He-cores (white dwarfs) after the end of their life. This type of stars should not ever go through core He-burning main sequence and, respectively, asymptotic giant branch (AGB) phase. But we'll never see their red giant branches (RGB) on the HR-diagram )</p>

CC BY-SA 4.0
2024-05-07T06:32:11.060Z
2024-05-15T12:12:06.697Z
2024-05-15T12:12:06.697Z
Take-oFF
<p>K-type dwarfs behave like stars of a solar mass star but on longer timescales, and will leave behind a (slightly) lower mass (<span class="math-container">$&lt;0.5M_\odot$</span>) white dwarf at the ends of their lives.</p>
<p>F-type dwarfs will behave like solar mass stars but on faster timescales and leave behind a (slightly) higher mass (<span class="math-container">$\sim 0.6M_\odot$</span>) white dwarf. In fact, these will be the progenitors of the most of the white dwarfs we see in our Galaxy.</p>
<p>Higher mass (hotter) stars will produce higher mass white dwarfs, up until the initial main sequence star is of about <span class="math-container">$8M_{\odot}$</span> (a spectral type of about B3V). The corresponding remnant white dwarf mass will increase up to about <span class="math-container">$\sim 1.2 M_{\odot}$</span> - which are the most massive white dwarfs produced via normal, single-star evolution.</p>
<p>All these stars will go through a &quot;first ascent&quot; red giant phase, He core burning and asymptotic giant branch phases.</p>
<p>Above an intial <span class="math-container">$8M_\odot$</span>, then carbon burning will be initiated in the core and it is likely<span class="math-container">$^\dagger$</span> that burning will continue through to iron, followed by core-collapse and a supernova.</p>
<p><span class="math-container">$\dagger$</span> It is possible that stars between <span class="math-container">$8-10M_\odot$</span>, which would be early B-stars on the main sequence, may halt burning at O/Ne/Mg and form a higher mass white dwarf or even explode directly in an <a href="https://en.wikipedia.org/wiki/Supernova#Electron-capture_supernovae" rel="nofollow noreferrer">electron capture supernova</a>.</p>

CC BY-SA 4.0
2020-04-01T16:34:36.233Z
Thanks. Do K-type dwarfs and F-type dwarfs produce red giants with a noticeable difference to ones produced by yellow dwarfs, or do they have little differences in size/color?
ut793
CC BY-SA 4.0
2020-04-01T19:05:58.040Z
@ut793 All the K-dwarfs ever born are still K-dwarfs! In theory they would be quite similar. Red giants lie close to the location of the Hayashi track.
ProfRob
CC BY-SA 4.0
2020-04-01T16:03:56.143Z
2024-05-07T10:22:49.980Z
2024-05-07T10:22:49.980Z
ProfRob
<p>I know that M (red dwarf) main-sequence stars slowly fade to white dwarf stars, and that G (yellow dwarf) main-sequence stars become red giants and then shed their outer layers in a planetary nebula leaving behind a white dwarf, but do K (orange dwarf) main stars take a similar route to red dwarfs? Or do they expand into red giants like yellow dwarfs?</p>

<p>What about F (yellow-white) main-sequence stars? Do they turn into supergiants and go supernova? Or do they take a similar route to yellow dwarfs? And what about A (white) and B (blue-white) main-sequence stars?</p>

CC BY-SA 4.0
2020-04-02T01:21:32.573Z
For my and other's reference: [$\color{blue}{O}\color{skyblue}{B}\color{lightblue}{A}\color{grey}{F}\color{lightgray}{G}\color{orange}{K}\color{red}{M}\color{brown}{L}\color{darkred}{T}\color{black}{Y}$](http://pono.ucsd.edu/~adam/teaching/phys160/obafgkmlty.html).
Nick T
CC BY-SA 4.0
2020-04-02T09:57:23.787Z
@NickT - can you edit that into the question, so it remains even if comments are cleared at some point in the future.
Rory Alsop
<star><stellar-evolution>
How do K, F, A and B stars die?
ut793
# How do K, F, A and B stars die?

(Asked by: username_0 on 2020-04-01)

I know that M (red dwarf) main-sequence stars slowly fade to white dwarf stars, and that G (yellow dwarf) main-sequence stars become red giants and then shed their outer layers in a planetary nebula leaving behind a white dwarf, but do K (orange dwarf) main stars take a similar route to red dwarfs? Or do they expand into red giants like yellow dwarfs?

What about F (yellow-white) main-sequence stars? Do they turn into supergiants and go supernova? Or do they take a similar route to yellow dwarfs? And what about A (white) and B (blue-white) main-sequence stars?

**Tags:** star, stellar-evolution

> **Comments:**
> **username_1**: For my and other's reference: [$\color{blue}{O}\color{skyblue}{B}\color{lightblue}{A}\color{grey}{F}\color{lightgray}{G}\color{orange}{K}\color{red}{M}\color{brown}{L}\color{darkred}{T}\color{black}{Y}$](http://pono.ucsd.edu/~adam/teaching/phys160/obafgkmlty.html).  
> **username_2**: @username_1 - can you edit that into the question, so it remains even if comments are cleared at some point in the future.  

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## 2 answers

### Answer by username_4 on 2020-04-01. Score: 11 | Accepted answer

K-type dwarfs behave like stars of a solar mass star but on longer timescales, and will leave behind a (slightly) lower mass ($<0.5M\_\odot$) white dwarf at the ends of their lives.

F-type dwarfs will behave like solar mass stars but on faster timescales and leave behind a (slightly) higher mass ($\sim 0.6M\_\odot$) white dwarf. In fact, these will be the progenitors of the most of the white dwarfs we see in our Galaxy.

Higher mass (hotter) stars will produce higher mass white dwarfs, up until the initial main sequence star is of about $8M\_{\odot}$ (a spectral type of about B3V). The corresponding remnant white dwarf mass will increase up to about $\sim 1.2 M\_{\odot}$ - which are the most massive white dwarfs produced via normal, single-star evolution.

All these stars will go through a "first ascent" red giant phase, He core burning and asymptotic giant branch phases.

Above an intial $8M\_\odot$, then carbon burning will be initiated in the core and it is likely$^\dagger$ that burning will continue through to iron, followed by core-collapse and a supernova.

$\dagger$ It is possible that stars between $8-10M\_\odot$, which would be early B-stars on the main sequence, may halt burning at O/Ne/Mg and form a higher mass white dwarf or even explode directly in an [electron capture supernova](https://en.wikipedia.org/wiki/Supernova#Electron-capture_supernovae).

> **Comments:**
> **username_0**: Thanks. Do K-type dwarfs and F-type dwarfs produce red giants with a noticeable difference to ones produced by yellow dwarfs, or do they have little differences in size/color?  
> **username_4**: @username_0 All the K-dwarfs ever born are still K-dwarfs! In theory they would be quite similar. Red giants lie close to the location of the Hayashi track.  

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### Answer by username_3 on 2024-05-07. Score: 0

I suppose, there must be some set of evolved early-type low-metallicity K-dwarfs that are going through or entering subgiant phase nowadays.

In theory, even early-type M-dwarfs with initial mass > 0.3 Msol can produce some kind of "small red giants", leaving He-cores (white dwarfs) after the end of their life. This type of stars should not ever go through core He-burning main sequence and, respectively, asymptotic giant branch (AGB) phase. But we'll never see their red giant branches (RGB) on the HR-diagram )


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