<p>My question is about sunspots size.</p>
<p>Does these spots have a 'typical' size for all kinds of stars (dwarves or  super giants), or are they dependent on a star size? In another words, is the statement correct:</p>
<blockquote>
<p>the bigger the star, so bigger the spots on it; if the star is smaller  smaller so is the spots accordingly. [In comparing to the Sun of course]</p>
</blockquote>

CC BY-SA 4.0
2020-12-25T21:41:42.600Z
I'd expect it be related to the magnetic field more (as a sun spot is a place of exceptionally strong magnetic field which supresses normal convection), and thus rotation and activity rather than size.
planetmaker
CC BY-SA 4.0
2020-12-25T22:09:46.243Z
So, the size of spots depends by magnetic fields (depends by mass) and not by size of star itself? Hence, the biggest spots must be on neutron stars surface?? But radius of this about 20 km, there size of sunspots about 3K km and more..
Uri Shlomy
CC BY-SA 4.0
2020-12-25T22:34:20.877Z
The distance to Betelgeuse hasn't been measured accurately by parallax yet because it's brightness non-uniformities make it look like it's photocenter is moving around randomly. I don't know if these are sunspots proper, or material around the star though: [Can New Horizons be used to measure the distance to Betelgeuse (despite its fickle photocenter)?](https://astronomy.stackexchange.com/q/39427/7982) and also [What will it finally take to accurately measure the distance to Betelgeuse?](https://astronomy.stackexchange.com/q/36365/7982)
uhoh
CC BY-SA 4.0
2020-12-25T22:34:59.573Z
For direct imaging of lumpy stellar disks see See also https://astronomy.stackexchange.com/a/34917/7982 and https://astronomy.stackexchange.com/a/34791/7982
uhoh
CC BY-SA 4.0
2020-12-25T22:44:43.810Z
Thanks for answers.The reason for my question is very simple: in my little project in Zooniverse for exoplanets hunting, we have used method of transition. Does it possible, that down of brightness was affected by huge spots and not by exoplanets themself?
Uri Shlomy
CC BY-SA 4.0
2020-12-25T23:15:32.613Z
The characteristic light curve should be different for sun spots and exoplanets as is the duration (though the limit of fast rotators might reach the limit of far-out planets). A recurring, long-lasting sun spot will have about 50% duty cycle ("eclipsing" the star) while a planet will never have that.
planetmaker
CC BY-SA 4.0
2020-12-29T20:36:32.173Z
You might also want to have a look at https://arxiv.org/pdf/1409.4337v1.pdf
B--rian
CC BY-SA 4.0
2020-12-29T21:07:36.297Z
planetmaker, B--rian, thanks a lot you both.  B--rian, very interesting and helpful article.
Uri Shlomy
CC BY-SA 4.0
2021-06-25T11:26:06.530Z
This is a topic of contemporary research.
ProfRob
<star><sunspots>
Sun (star) spots (size)
Uri Shlomy
# Sun (star) spots (size)

(Asked by: username_0 on 2020-12-25)

My question is about sunspots size.

Does these spots have a 'typical' size for all kinds of stars (dwarves or super giants), or are they dependent on a star size? In another words, is the statement correct:

> the bigger the star, so bigger the spots on it; if the star is smaller smaller so is the spots accordingly. [In comparing to the Sun of course]

**Tags:** star, sunspots

> **Comments:**
> **username_1**: I'd expect it be related to the magnetic field more (as a sun spot is a place of exceptionally strong magnetic field which supresses normal convection), and thus rotation and activity rather than size.  
> **username_0**: So, the size of spots depends by magnetic fields (depends by mass) and not by size of star itself? Hence, the biggest spots must be on neutron stars surface?? But radius of this about 20 km, there size of sunspots about 3K km and more..  
> **username_2**: The distance to Betelgeuse hasn't been measured accurately by parallax yet because it's brightness non-uniformities make it look like it's photocenter is moving around randomly. I don't know if these are sunspots proper, or material around the star though: [Can New Horizons be used to measure the distance to Betelgeuse (despite its fickle photocenter)?](https://astronomy.stackexchange.com/q/39427/7982) and also [What will it finally take to accurately measure the distance to Betelgeuse?](https://astronomy.stackexchange.com/q/36365/7982)  
> **username_2**: For direct imaging of lumpy stellar disks see See also https://astronomy.stackexchange.com/a/34917/7982 and https://astronomy.stackexchange.com/a/34791/7982  
> **username_0**: Thanks for answers.The reason for my question is very simple: in my little project in Zooniverse for exoplanets hunting, we have used method of transition. Does it possible, that down of brightness was affected by huge spots and not by exoplanets themself?  
> **username_1**: The characteristic light curve should be different for sun spots and exoplanets as is the duration (though the limit of fast rotators might reach the limit of far-out planets). A recurring, long-lasting sun spot will have about 50% duty cycle ("eclipsing" the star) while a planet will never have that.  
> **username_3**: You might also want to have a look at https://arxiv.org/pdf/1409.4337v1.pdf  
> **username_0**: username_1, username_3, thanks a lot you both.  username_3, very interesting and helpful article.  
> **username_4**: This is a topic of contemporary research.  

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## 0 answers

