<p>A large amount of light elements would be required for them to fuse, amounts not normally found concentrated together in the universe. The closest thing would be Wolf–Rayet stars that fuse hydrogen on their outer layers and heavier elements within. Also, if non-hydrogen stars existed, they would have a shorter lifespan as at the end of a stars life, it fuses everything into iron and dies.</p>

CC BY-SA 4.0
2021-08-19T07:40:20.453Z
Most stars do not produce iron in their cores at any stage in their lives.
ProfRob
CC BY-SA 4.0
2021-08-18T00:39:25.490Z
2021-08-18T00:46:01.730Z
2021-08-18T00:46:01.730Z
Anti-Thorium
<p>No.  The (unofficial) definition of &quot;star&quot; is &quot;a body supported by the pressure generate by fusion in its core&quot;.  For fusion to occur a certain temperature must be reached, and most other elements have a much higher temperature and pressure requirements for fusion than hydrogen.</p>
<p>It is impractical to form a star from anything else, because hydrogen is so widespread. Interstellar gas is 75% hydrogen, everywhere, and it is very well mix.  You simply don't get clouds of helium or neon. Even when the gas is enriched with other elements (eg from a kilonova explosion), hydrogen will still be a major component.</p>
<p>Stars initially fuse lithium, as the Li+H reaction occurs at a slightly lower temperature. There is a class of Brown Dwarf (with a mass of greater than 65 Jupiters) that slowly fuse their Lithium, however not at a rate that will provide substantial heat and pressure and such objects are not, therefore, stars in the strict sense. They also don't look much like &quot;stars&quot; glowing at most dim red.</p>
<p>Deuterium (an isotope of Hydrogen) will star to fuse even earlier and this releases more energy than Lithium burning.  There is a class of brown dwarfs that are established for a brief period by deuterium fusion.  A chemist would probably count deuterium as the same as hydrogen, but a nuclear physicist might consider them to be different species.</p>
<p>So the answer in the spirit that the question was asked is that every &quot;star&quot; starts by fusing hydrogen of one sort or another.</p>

CC BY-SA 4.0
2021-08-19T07:38:33.693Z
Deuterium burning is first and considerably more energy is released than in Li burning; enough that there is a brief "D-burning main sequence" for low-mass objects.
ProfRob
CC BY-SA 4.0
2021-08-19T08:14:24.073Z
I thought of that, but then Deuterium is an isotope of Hydrogen, and I felt the sprit of the question was asking about "stars" burning a completely different element.
James K
CC BY-SA 4.0
2021-08-19T07:33:11.870Z
2021-08-19T08:19:27.110Z
2021-08-19T08:19:27.110Z
James K
<p>As far as I know, stars (virtually all stars) begin fusing hydrogen into helium, and the rest happens based on the mass and luminosity and etc.</p>
<p>Out of curiosity, I was wondering: is it even possible for a star to not begin with this hydrogen fusion at all - as in, fuse possibly another element - and still survive with an average-star lifespan?</p>
<p>Or, is is possible for a star to form out of an interstellar cloud containing insubstantial hydrogen?</p>

CC BY-SA 4.0
2021-08-17T22:47:56.550Z
Is this different from a [brown dwarf](https://en.wikipedia.org/wiki/Brown_dwarf)?
Mike G
CC BY-SA 4.0
2021-08-17T22:51:55.423Z
do you know what the definition of a star is?
user177107
CC BY-SA 4.0
2021-08-17T23:01:50.377Z
What would you count as a beginning? How about some ejecta from a supernova that was already fusing heavier elements? (Not that it would continue to do so.)
D. Halsey
CC BY-SA 4.0
2021-08-17T23:17:55.630Z
By beginning, I mean when the a gas cloud collapses to form a protostar.
AdiBak
CC BY-SA 4.0
2021-08-18T06:24:54.390Z
How do you propose collecting enough matter to form a star without gathering a substantial amount of hydrogen?
PM 2Ring
<star><stellar-evolution><hydrogen><element>
Is it possible for stars to not begin fusing hydrogen at all?
AdiBak
# Is it possible for stars to not begin fusing hydrogen at all?

(Asked by: username_0 on 2021-08-17)

As far as I know, stars (virtually all stars) begin fusing hydrogen into helium, and the rest happens based on the mass and luminosity and etc.

Out of curiosity, I was wondering: is it even possible for a star to not begin with this hydrogen fusion at all - as in, fuse possibly another element - and still survive with an average-star lifespan?

Or, is is possible for a star to form out of an interstellar cloud containing insubstantial hydrogen?

**Tags:** star, stellar-evolution, hydrogen, element

> **Comments:**
> **username_1**: Is this different from a [brown dwarf](https://en.wikipedia.org/wiki/Brown_dwarf)?  
> **username_2**: do you know what the definition of a star is?  
> **username_3**: What would you count as a beginning? How about some ejecta from a supernova that was already fusing heavier elements? (Not that it would continue to do so.)  
> **username_0**: By beginning, I mean when the a gas cloud collapses to form a protostar.  
> **username_4**: How do you propose collecting enough matter to form a star without gathering a substantial amount of hydrogen?  

---

## 2 answers

### Answer by username_7 on 2021-08-19. Score: 4 | Accepted answer

No. The (unofficial) definition of "star" is "a body supported by the pressure generate by fusion in its core". For fusion to occur a certain temperature must be reached, and most other elements have a much higher temperature and pressure requirements for fusion than hydrogen.

It is impractical to form a star from anything else, because hydrogen is so widespread. Interstellar gas is 75% hydrogen, everywhere, and it is very well mix. You simply don't get clouds of helium or neon. Even when the gas is enriched with other elements (eg from a kilonova explosion), hydrogen will still be a major component.

Stars initially fuse lithium, as the Li+H reaction occurs at a slightly lower temperature. There is a class of Brown Dwarf (with a mass of greater than 65 Jupiters) that slowly fuse their Lithium, however not at a rate that will provide substantial heat and pressure and such objects are not, therefore, stars in the strict sense. They also don't look much like "stars" glowing at most dim red.

Deuterium (an isotope of Hydrogen) will star to fuse even earlier and this releases more energy than Lithium burning. There is a class of brown dwarfs that are established for a brief period by deuterium fusion. A chemist would probably count deuterium as the same as hydrogen, but a nuclear physicist might consider them to be different species.

So the answer in the spirit that the question was asked is that every "star" starts by fusing hydrogen of one sort or another.

> **Comments:**
> **username_6**: Deuterium burning is first and considerably more energy is released than in Li burning; enough that there is a brief "D-burning main sequence" for low-mass objects.  
> **username_7**: I thought of that, but then Deuterium is an isotope of Hydrogen, and I felt the sprit of the question was asking about "stars" burning a completely different element.  

---

### Answer by username_5 on 2021-08-18. Score: 3

A large amount of light elements would be required for them to fuse, amounts not normally found concentrated together in the universe. The closest thing would be Wolf–Rayet stars that fuse hydrogen on their outer layers and heavier elements within. Also, if non-hydrogen stars existed, they would have a shorter lifespan as at the end of a stars life, it fuses everything into iron and dies.

> **Comments:**
> **username_6**: Most stars do not produce iron in their cores at any stage in their lives.  

---

