Workshop

Interior talks

Please find below the talks of people who work mainly on determining/understanding the interior structure of planets.

You can leave questions below the video of each speaker! These questions will then be asked to the speaker the day of the workshop.

Jon F. Otegi: Impact of the measured parameters of exoplanets on the inferred internal structure
Alexander Grayver: Electromagnetic induction heating in rocky planets
Rob Spaargaren: Compositional diversity of terrestrial exoplanets, influence on geodynamics
Haiyang Wang: From accurate stellar composition to exoplanet interiors and beyond
Oliver Shah: Internal water storage capacity of terrestrial planets and the effect of hydration on the MR-relation 
Jonas Haldemann: AQUA: A Collection of H2O Equation of State for Planetary Models

 



 

 

Jon F. Otegi:

Impact of the measured parameters of exoplanets on the inferred internal structure

 

Ask your questions to Jon!

Posted by Emeline on
Hello Jon,
Thanks for the interesting talk!

I have a few questions:
(1) Concerning your interior model: will you allow at some point for water to be gaseous?
(2) I understand that you don't account for the temperature of the planets for your synthetic planets. How do you plan to take this into account eventually?
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Alexander Grayver:

Electromagnetic induction heating in rocky planets

 

Ask your questions to Alexander!

Posted by bolmonte on
Hi Alexander and welcome to PlanetS!
Thanks for the nice talk :-) It was very interesting!

I had a few questions for you:
1) I was wondering if you had an opinion about the article Kislyakova et al. 2017 (https://ui.adsabs.harvard.edu/abs/2017NatAs...1..878K/abstract), where they look at the induction heating for the TRAPPIST-1 planets. Are their conclusions similar to yours?
2) About the example you give of an earth-like planet. There is a ring, for which the dissipation is stronger, for a separation of ~0.03. Why is that? Some kind of resonance? Or is it the Alfven radius?
3) Did you try to compare the two sources of EM heating you mention to tidal heating for instance? In a recent article (https://ui.adsabs.harvard.edu/abs/2020A%26A...644A.165B/abstract), we give some estimates for the tidal heating for the outer planets of TRAPPIST-1 (e to h). I'd be happy to talk to you about that if you're interested to compare!
Posted by Martin Turbet on
Hi Alexander,

Thank you for your presentation!

I have two questions for you:

(1) How do you calculate the amplitude of the magnetic perturbation of the stellar flares? And what fraction of the energy that is carried by the stellar flare (that reaches the planet) typically gets dissipated in the planetary interior?

(2) When you say that EM can produce magma oceans, do you mean subsurface magma oceans?
Posted by Alexander on
Dear Emeline
Thanks for the interest! Below are answers:

1) Yes, I think that conclusions are similar, subject to certain assumptions they made... Also note they considered only the effect of stellar magnetic field and this work also add effect of flares.

2) I think you refer to a region at a fixed r~0.03 where dissipation is actually much weaker (dark corresponds to small on this colorscale...). This happens because period of star's rotation and planet's orbital period become very close.

3) Yes, absolutely! If you do not mind, I would follow up on that in an email to you.

Best
Alexander
Posted by Alexander on
Dear Martin
Thanks for the questions!

1) What is shown in the presentation is already the amount of the heat that is dissipated (i.e. converted into heat within the planet). The magnetic pertubation is calculated using a model that we have for our solar system and that was adjusted to the TRAPPIST-1 star.

2) Well, I guess what I meant is that it can facilitate melting and since most heating is concentrated in the upper part of a planet due to the skin depth effect, the melting would also occur there...

Happy to discuss further!
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Rob Spaargaren:

Compositional diversity of terrestrial exoplanets, influence on geodynamics

 

Ask your questions to Rob!

Posted by Martin Turbet on
Hello Rob,

Thank you for your presentation!

Do you expect a systematic trend (based on stellar abundance + devolatilization) in terrestrial planet composition depending on the stellar type (from G stars to late M-dwarfs)?
Posted by Emeline on
Hi Rob,
Thanks for the interesting talk!

I have a few questions:
(1) About your results on the mantle mineralogy, the different panels you show on slide 11 with different ratios of Fe/Mg/Si span the diversity of the stellar abundances you discuss in the beginning?
(2) Between these four panels, would you say that the outgassed atmosphere would be (noticeably) very different? Or in other words, by looking at the atmosphere, could we infer to which of the four panel the planet belongs to?
Posted by Rob Spaargaren on
Thanks for the questions!

@Martin: I do not observe any significant compositional trend in my stellar abundances as a function of stellar type. The Hypatia catalog contains only F, G, and K-stars, so I cannot say anything about M-dwarfs. As for the devolatilization trend, I do not expect that the devolatilization trend changes as a function of stellar type, though the differences in stellar evolution between types may have a small effect on the planet formation processes.

@Emeline:
1) The panels span the full range in terms of Mg/Si and bulk planet Fe/Mg. However, these are just three of the twenty end-member compositions that together fully span the compositional range. I will publish such mineralogical profiles for each of the twenty compositions in the paper that I'm currently writing, so stay tuned!
2) Unfortunately, I really cannot say yet at this moment. It depends on how thermal evolution is affected by the different compositions, and how different the melting behaviour and volatile storage capacity is for each of these compositions. I expect there to be quite some differences, since on Earth, most of the water stored in the mantle is stored in Wadsleyite and Ringwoodite, which have abundances of 60 vol% In the transition zone on Earth. In these three compositions, the Wad+Ring abundances range from 10% to 70%, which will definitely affect the distribution of water between the interior and the surface. Additionally, this variety in mineralogy will likely lead to different melting behaviour, since it's much easier to melt Opx+Cpx than olivine (O). I expect that there will be an effect of the composition on the atmosphere. But I cannot say how significant this effect is, and therefore if it'll be observable. That's something that I will find out in my future work!
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Haiyang Wang:

From accurate stellar composition to exoplanet interiors and beyond

 

Ask your questions to Haiyang!

Posted by Emeline on
Hi Haiyang,
Thanks for the nice presentation!

I have a few questions:
(1) About your constraints about the composition of the exoE planets: what is the lowest stellar mass in the sample?
(2) Is there a trend in stellar mass we could extrapolate to even lower mass stars for which we don't have the luxury of constraining their composition?
Posted by Haiyang on
Hi Emeline,

Thanks for your questions.

1) These planet-hosting stars are all Sun-like stars, with the lowest stellar mass in the sample at 0.8 solar mass.

2) did you mean a trend of devolatilization or stellar abundances? For the former, we're currently working on extending the trend to different types of stars - stay tuned; for the latter, I'm not aware of such an extrapolation yet and would be happy to look into it. Yes, it's a pain for the modeling of M-stars' photospheric compositions, even though we can indeed measure well their masses and radii.

Thanks and let me know if I can be more helpful.
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Oliver Shah:

Internal water storage capacity of terrestrial planets and the effect of hydration on the MR-relation

 

Ask your questions to Oliver!

Posted by Martin Turbet on
Hi Oliver,

Thank you for this super refreshing talk ;) (it even made me dance!)

It is very interesting to see this hydration effect being well quantified!

My questions are:

(1) What would be the best way now to find out (for a low-irradiated low-mass exoplanet) the fraction of water expected to be trapped in hydrated minerals vs surface layers?

(2) What about solar system rocky planets? Do we have any good constraints on the amount of water trapped in hydrated minerals?
Posted by bolmonte on
Wow, that's original! Nice video, Oliver!

I have a few questions:
(1) In your different types of planets (1, 2, 3), why didn't you consider a hydrated interior and an ocean on top? Is it because if there is an ocean it's likely to be so deep that there will be an ice layer between the rock and the ocean?
(2) Can we learn something from considering/simulating "younger planets", which have some leftover heat which could prevent the ice layer to isolate rock and liquid water? Or if it's not younger planets, there are mechanisms to heat up a planet (through tides or induction as in Alexander's talk). What would be the impact of that?
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Jonas Haldemann:

AQUA: A Collection of H2O Equation of State for Planetary Models 

Ask your questions to Jonas!

Posted by Emeline on
Hi Jonas,
Thanks for the nice and clear talk!

How easy is it to use AQUA in an other code, like the ones of Jon or Oliver?
Posted by Jonas on
Hi Emeline

It is pretty easy, it is a tabulated EoS. On github (https://github.com/mnijh/aqua) I also provide a small fortran routine, to interpolate the table. For any other language one can use a standard interpolation method to evaluate the table.

Regarding the codes of Jon and Oliver. I'm not exactly sure what you mean. So the structure model Jon is using was written by myself.
So that should work for sure. Though I don't know if he plans to further update his code base. If you need some characterization of a planet, my characterization code has it already implemented, just drop me an email.
For Oliver, it should not be a problem either
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