<p>In a nova, a layer of hydrogen is pulled from a regular star, forming a kind of dense atmosphere around the white dwarf. This atmosphere is heated by the white dwarf, until a critical temperature is reached, and fusion begins in the atmosphere. The white dwarf is rather unaffected by this, and the process of forming a hydrogen atmosphere can restart. Recurrent novae are well known.</p>
<p>In a type 1a supernova, the mass of the white dwarf increases towards the Chandrasekhar mass, of about 1.44 sun-masses.  At this point, the degenerate carbon and oxygen, which the white dwarf is mostly composed of, begins to fuse.  The energy released is enough to completely unbind the white dwarf.</p>
<p>In a nova it is only the hydrogen atmosphere that explodes.  In a supernova it is the whole carbon-oxygen star.</p>

CC BY-SA 4.0
2021-07-20T07:37:31.567Z
"This atmosphere is heated by the nova", should this be "This atmosphere is heated by the white dwarf"? As at this stage, the star should still be classified as a white dwarf?
Jack the Ranger
CC BY-SA 4.0
2021-07-18T16:37:58.673Z
2021-07-20T07:38:14.150Z
2021-07-20T07:38:14.150Z
James K
<p>What is the difference between Supernova Type Ia and Nova? Base on a web search, they seem to have a similar formation process, as they are both white dwarfs in a binary system who absorb masses from their companions. But they result different in mass ejection, brightness and lasting time.</p>

<supernova><nova>
Difference between Supernova Type Ia and Nova
Jack the Ranger
# Difference between Supernova Type Ia and Nova

(Asked by: username_0 on 2021-07-18)

What is the difference between Supernova Type Ia and Nova? Base on a web search, they seem to have a similar formation process, as they are both white dwarfs in a binary system who absorb masses from their companions. But they result different in mass ejection, brightness and lasting time.

**Tags:** supernova, nova


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## 1 answers

### Answer by username_1 on 2021-07-18. Score: 5 | Accepted answer

In a nova, a layer of hydrogen is pulled from a regular star, forming a kind of dense atmosphere around the white dwarf. This atmosphere is heated by the white dwarf, until a critical temperature is reached, and fusion begins in the atmosphere. The white dwarf is rather unaffected by this, and the process of forming a hydrogen atmosphere can restart. Recurrent novae are well known.

In a type 1a supernova, the mass of the white dwarf increases towards the Chandrasekhar mass, of about 1.44 sun-masses. At this point, the degenerate carbon and oxygen, which the white dwarf is mostly composed of, begins to fuse. The energy released is enough to completely unbind the white dwarf.

In a nova it is only the hydrogen atmosphere that explodes. In a supernova it is the whole carbon-oxygen star.

> **Comments:**
> **username_0**: "This atmosphere is heated by the nova", should this be "This atmosphere is heated by the white dwarf"? As at this stage, the star should still be classified as a white dwarf?  

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