<p>As ProfRob noted, M dwarfs emit mostly in the infra-red.  But there is no reason to think that &quot;photosynthesis&quot; would be the same on an alien planet. Photosynthesis has evolved on Earth to take advantage of the wavelengths of light that the sun emits.  One would assume that on a planet orbiting an M-dwarf star, that photosynthesis would evolve differently, and plant life would gather energy in a different part of the spectrum.</p>

CC BY-SA 4.0
2023-02-08T01:12:55.450Z
As proof of that, photosynthesis appeared relatively “late” in Earth’s history, and many “plant-like” organisms still don’t use it, for example near hydrothermal vents at the bottom of oceans.
Pierre Paquette
CC BY-SA 4.0
2023-02-06T23:24:53.773Z
2023-02-06T23:24:53.773Z
James K
<p>I read a lot of press as of late about earth size planets around the habitable zone of M dwarf stars. I am not an astronomer but I assume this means that the distance will allow liquid water to exist.</p>
<p>I was curious if any studies were done of what the electromagnetic spectrum would be and it's strength at the distance that the earth like planets are discovered and if that was adequate for photosynthesis to occur? Google didn't help much on this and I probably shouldn't even ask.</p>
<p>I won't be disappointed if I hear we don't have instruments that will do that yet. This is difficult science for sure.</p>

CC BY-SA 4.0
2023-02-06T23:02:21.517Z
It's actually quite easy. M-dwarfs emit most of their power in the infrared.
ProfRob
CC BY-SA 4.0
2023-08-19T04:08:53.247Z
related: [Is life (as we know it) even possible around M-class stars?](https://astronomy.stackexchange.com/q/54442/7982)
uhoh
<exoplanet><astrobiology><dwarf-star>
Do M dwarf stars emit the wavelengths of the electromagnetic spectrum necessary for photosynthesis?
Sedumjoy
# Do M dwarf stars emit the wavelengths of the electromagnetic spectrum necessary for photosynthesis?

(Asked by: username_0 on 2023-02-06)

I read a lot of press as of late about earth size planets around the habitable zone of M dwarf stars. I am not an astronomer but I assume this means that the distance will allow liquid water to exist.

I was curious if any studies were done of what the electromagnetic spectrum would be and it's strength at the distance that the earth like planets are discovered and if that was adequate for photosynthesis to occur? Google didn't help much on this and I probably shouldn't even ask.

I won't be disappointed if I hear we don't have instruments that will do that yet. This is difficult science for sure.

**Tags:** exoplanet, astrobiology, dwarf-star
> **Comments:**
> **username_1**: It's actually quite easy. M-dwarfs emit most of their power in the infrared.  
> **username_2**: related: [Is life (as we know it) even possible around M-class stars?](https://astronomy.stackexchange.com/q/54442/7982)  

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## 1 answers

### Answer by username_3 on 2023-02-06. Score: 4 | Accepted answer

As ProfRob noted, M dwarfs emit mostly in the infra-red. But there is no reason to think that "photosynthesis" would be the same on an alien planet. Photosynthesis has evolved on Earth to take advantage of the wavelengths of light that the sun emits. One would assume that on a planet orbiting an M-dwarf star, that photosynthesis would evolve differently, and plant life would gather energy in a different part of the spectrum.

> **Comments:**
> **username_4**: As proof of that, photosynthesis appeared relatively “late” in Earth’s history, and many “plant-like” organisms still don’t use it, for example near hydrothermal vents at the bottom of oceans.  

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