<p>The magnetic activity is driven by a dynamo that relies on a combination of rotation and convection.</p>

<p>M dwarfs have large convection zones or are fully convective beyond spectral type M4. They also have much longer spin-down timescales than G- and K-dwarfs; billions of years rather than tens of millions of years.</p>

<p>This means that a large fraction of cool M dwarfs are rotating fast and have deep convection zones.</p>

<p>This is the basic reason, but it is still a very busy research area.</p>

CC BY-SA 4.0
2018-12-20T05:55:50.760Z
2018-12-20T05:55:50.760Z
ProfRob
<p>Why are M dwarf stars the most active (in terms of starspots and faculae) of all stars? </p>

<star><stellar-evolution><star-formation><stellar-astrophysics><starspot>
Activity of M dwarf stars
user4437416
# Activity of M dwarf stars

(Asked by: username_0 on 2018-12-20)

Why are M dwarf stars the most active (in terms of starspots and faculae) of all stars?

**Tags:** star, stellar-evolution, star-formation, stellar-astrophysics, starspot

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## 1 answers

### Answer by username_1 on 2018-12-20. Score: 7 | Accepted answer

The magnetic activity is driven by a dynamo that relies on a combination of rotation and convection.

M dwarfs have large convection zones or are fully convective beyond spectral type M4. They also have much longer spin-down timescales than G- and K-dwarfs; billions of years rather than tens of millions of years.

This means that a large fraction of cool M dwarfs are rotating fast and have deep convection zones.

This is the basic reason, but it is still a very busy research area.


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