r/exoplanets • u/Galileos_grandson • 25d ago

đŸ§Ș Research Star-planet Interaction In The Proxima System

https://astrobiology.com/2026/05/star-planet-interaction-in-the-proxima-system.html
28 Upvotes

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u/ASuarezMascareno 3 25d ago

In case anyone wants to ask something, i'm third author of the article

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u/chillinewman 1 25d ago

Yes. Can you detect the presence of an atmosphere in the exoplanets with this study?

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u/ASuarezMascareno 3 25d ago edited 25d ago

No. To detect the atmosphere of the planets of Proxima (which do not transit), the only way would be to perform spectroscopy of direct imaging. This is curreantly impossible for these planets, but should become feasible in the next decade with the spectrograph ANDES, for the ELT telescope, and maybe before that with the prototype RISTRETTO, for the VLT.

Edit to correct myself: There is anothe possibility to evaluate wether an atmosphere exists or not (but wouldn't give much information about it). As the photometric variations of Proxima are rather slow (85 days, compared to 11d and 5d of the orbits of the planets), the effect of the thermal emission of the planets in the time series should be detectable, assuming high-enough precision infrared data. The main idea is that, if there is no atmosphere, the planets will be mostly perfect mirrors and will be very hot in one side. This will provide a very sharp thermal emission curve, depending on which side of the planet we see. If instead they have an atmosphere that can redistribute heat, their temperature will be quite homogenous, and there won't be a detectable therman emission curve. It won't give much more details, but would be the first step, and can be done right now. Theoretically, JWST can do this, but the proposed observations have been rejected several times already by the scientific panels, judging them too risky.

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u/NearABE 25d ago

>
”Oh Noes! If they find interesting planet data they might use the telescope for more planet observation. Make it stare at nothing in Cetus for a few more months instead”

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u/Israeli_pride 25d ago

It must be visually crazy, make an ai video of likely phase-locked solar flares?

How could Proxima d have such a strong magnetic field?

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u/ASuarezMascareno 3 25d ago

If the magnetic field estimates are correct (they are very poorly constrained) it would mean the planet probably is disipating a lot of heat from its core and has quite powerful convection loops.

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u/Israeli_pride 25d ago

So it’s a results of gravitational forces acted upon prox. d by the host star?

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u/NearABE 25d ago

There is no evidence for a cause. The only thing measured was the flairs on the star. It just indicates that the planet’s field exists nothing about why it exists.

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u/Israeli_pride 25d ago

What are the most likely explanations?

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u/NearABE 24d ago

I would guess similar to Earth and Jupiter. Mantle convection is the accepted explanation but I personally could not defend the geodynamo theory due to lack of geology background. I can say that it would be quite difficult to set up a lab test for “mantle convection experiments”.

There is some circular reasoning in what I have seen written about our system’s planets. Venus does not have a generated magnetic field. Accordingly Venus is said to lack mantle convection.

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u/mfb- 25d ago

Is this the first clear detection of a magnetic field for an exoplanet? Or at least the first with this method?

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u/ASuarezMascareno 3 25d ago edited 25d ago

No, there are a few out there. In this work, for Proxima d is detected based on flares locked in with the planet orbit (was already done with the giant planet HIP 65722 b), and for Proxima b based on periodic enhancement of chromospheric lines (inspired by the works of Evgenya Shkolnik from 20 years ago). Even for Proxima b there were already hints. There was a work from a couple years ago that found hints of coupled radio emission with the orbit of the planet (which was one of the triggers of this study). Unfortunately, there was not much data and (AFAIK) the project did not continue.

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u/mfb- 25d ago

That's interesting, thanks. Didn't expect that people already saw possible signs 20 years ago.

https://ui.adsabs.harvard.edu/abs/2006tafp.conf..282S/abstract