<h1> Because the Red-Giant Sun can fuse carbon to oxygen </h1>
<p>But, the process is extremely slow. The Sun is too light to actually fuse carbon to oxygen on a large scale. You need much more mass to do that.</p>
<p>So instead, the Sun simply fuses it passively. But the Sun does not do <strong>carbon+carbon=oxygen</strong> fusion. It instead uses <strong>carbon+helium</strong>, where a helium nucleus (essentially an alpha particle) is bombarded onto a carbon nucleus, forming oxygen.</p>
<p>But even this process is really slow, as there is not much mass. So this process is merely a byproduct, a trace product of the dominant helium-fusing core of a red-giant.</p>

CC BY-SA 4.0
2022-10-24T19:30:33.213Z
The OP doesn't ask about the Sun.
PM 2Ring
CC BY-SA 4.0
2022-10-25T06:00:25.050Z
I only used it as an example
Arcturus
CC BY-SA 4.0
2022-10-24T14:41:52.090Z
2022-10-24T14:41:52.090Z
Arcturus
<p>Some oxygen is produced during CNO cycle processing of hydrogen, starting with carbon nuclei. Oxygen is also produced by alpha capture onto carbon nuclei at temperatures well below 350 million K.</p>

<p>Both of these occur in and around the cores of low mass stars before they become white dwarfs. Neon production is not required.</p>

CC BY-SA 3.0
2016-05-24T19:43:56.247Z
2016-05-24T22:10:39.700Z
2016-05-24T22:10:39.700Z
ProfRob
<p>I’ve got a question about white dwarfs and oxygen.</p>

<p>I read in a book that a temperature of 100 million degrees is required to fuse Helium in the core of a red giant. The Helium fuses into Carbon by the triple-alpha process. </p>

<p>It’s also written that, after a temperature of 350 million degrees is reached, the core of a red giant ceases to be degenerate. So, the core is able to expand and its temperature is controlled. The core won't reach a temperature of more than 350 million.</p>

<p>But my teacher has said that a temperature of 600 million degrees is needed to form Oxygen from Carbon: Carbon fuses into Neon and by photodisintegration gives Oxygen. </p>

<p>So, how can there be Oxygen in white dwarfs, if we don't reach a temperature higher than 350 million degrees? By what process can oxygen be formed in a red giant? </p>

<white-dwarf><red-giant>
How can white dwarf form Oxygen ? (Temperature problem)
jerome55
# How can white dwarf form Oxygen ? (Temperature problem)

(Asked by: username_0 on 2016-05-24)

I’ve got a question about white dwarfs and oxygen.

I read in a book that a temperature of 100 million degrees is required to fuse Helium in the core of a red giant. The Helium fuses into Carbon by the triple-alpha process.

It’s also written that, after a temperature of 350 million degrees is reached, the core of a red giant ceases to be degenerate. So, the core is able to expand and its temperature is controlled. The core won't reach a temperature of more than 350 million.

But my teacher has said that a temperature of 600 million degrees is needed to form Oxygen from Carbon: Carbon fuses into Neon and by photodisintegration gives Oxygen.

So, how can there be Oxygen in white dwarfs, if we don't reach a temperature higher than 350 million degrees? By what process can oxygen be formed in a red giant?

**Tags:** white-dwarf, red-giant


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## 2 answers

### Answer by username_3 on 2016-05-24. Score: 5 | Accepted answer

Some oxygen is produced during CNO cycle processing of hydrogen, starting with carbon nuclei. Oxygen is also produced by alpha capture onto carbon nuclei at temperatures well below 350 million K.

Both of these occur in and around the cores of low mass stars before they become white dwarfs. Neon production is not required.


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### Answer by username_1 on 2022-10-24. Score: 0

# Because the Red-Giant Sun can fuse carbon to oxygen

But, the process is extremely slow. The Sun is too light to actually fuse carbon to oxygen on a large scale. You need much more mass to do that.

So instead, the Sun simply fuses it passively. But the Sun does not do **carbon+carbon=oxygen** fusion. It instead uses **carbon+helium**, where a helium nucleus (essentially an alpha particle) is bombarded onto a carbon nucleus, forming oxygen.

But even this process is really slow, as there is not much mass. So this process is merely a byproduct, a trace product of the dominant helium-fusing core of a red-giant.

> **Comments:**
> **username_2**: The OP doesn't ask about the Sun.  
> **username_1**: I only used it as an example  

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