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John Ilee @johnilee.bsky.social · 1d

So, the main takeaway: you need to correctly account for dust evolution and ice chemistry when trying to understand complex molecules in planet forming disks!

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John Ilee @johnilee.bsky.social · 1d

Unfortunately including this is time consuming and computationally difficult, but ultimately we think this is going to be the only way to reconcile the models with the observations in the future.

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John Ilee @johnilee.bsky.social · 1d

So what is this telling us? A big limitation of the modelling here is that it is static, but we know dust grains move radially and vertically in disks and can redistribute molecules when they do so.

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John Ilee @johnilee.bsky.social · 1d

The second surprising result is that even after throwing the chemical kitchen sink at the model (honestly, see Table 2) we could *not* reproduce the column density profile of methanol. We didn't have enough of it (short by ~1-2 orders of magnitude) and it was all in the wrong place (the outer disk).

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John Ilee @johnilee.bsky.social · 1d

TW Hya is great because it's so well studied and there is a wealth of information on the disk physical structure. We combined some pretty advanced chemical modelling (thanks to Catherine) with a really well benchmarked model of the disk (thanks to Jenny).

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John Ilee @johnilee.bsky.social · 1d

Our first surprising result was than the methanol was cold (~35K) suggesting it wasn't coming from thermal desorption of ices on dust grains, but instead by non-thermal processes. This led us to start looking more into how it could be formed chemically…

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John Ilee @johnilee.bsky.social · 1d

We can look at the relative intensities of each of these transitions to pull out physical information like excitation temperature and column density for the methanol gas, and since the observations were spatially resolved, we see how these change radially through the disk.

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John Ilee @johnilee.bsky.social · 1d

Methanol is the starting point for lots of important prebiotic chemistry. So far it has only been detected in a disk around one solar-type star, TW Hya. We used #ALMA to go back and get some very sensitive, high-resolution observations of multiple transitions for the first time.

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John Ilee @johnilee.bsky.social · 1d

Great to see our paper on methanol in TW Hya finally come out today (with Catherine Walsh and Jenny Calahan). A quick overview.... 🔭 ☄️ #radioastro

arxiv.org/abs/2510.04106

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John Ilee @johnilee.bsky.social · 1d

Ultimately, we think including these types of processes is going to be the only way to reconcile the models with the observations. But the main takeaway is that the distribution of important prebiotic molecules in disks is likely highly dependent on treating dust (and ice) evolution correctly!

John Ilee @johnilee.bsky.social · 1d

So what is this telling us? A big limitation of the modelling here is that it is static, but we know dust grains move radially and vertically in disks and can redistribute molecules when they do so.

1

John Ilee @johnilee.bsky.social · 1d

The second surprising result is that, even after throwing the chemical kitchen sink at the model, we could *not* reproduce the column density profile of methanol. We didn’t have enough of it (short by ~1-2 orders of magnitude) and it was all in the wrong place (the outer disk).

1

John Ilee @johnilee.bsky.social · 1d

TW Hya is great because it’s so well studied and there is a wealth of information on the disk physical structure. We combined some pretty advanced chemical modelling (Catherine) with a benchmarked model of the disk (Jenny).

1

John Ilee @johnilee.bsky.social · 1d

Our first surprising result was than the methanol was cold (~35K) suggesting it wasn’t coming from thermal desorption of ices on dust grains, but instead by non-thermal processes. This led us to start looking more into how it could be formed chemically.

1

John Ilee @johnilee.bsky.social · 1d

We can look at the relative intensities of each of these transitions to pull out physical information like excitation temperature and column density for the methanol gas, and since the observations were spatially resolved, we can look at how these change radially through the disk.

1

John Ilee @johnilee.bsky.social · 1d

Methanol is the starting point for lots of important prebiotic chemistry. So far it has only been detected in a disk around one solar-type star, TW Hya. We used #ALMA to go back and get some very sensitive, high-resolution observations of multiple transitions for the first time.

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Reposted by John Ilee

arXiv bot (astro-ph) @krxiv-astro-ph.bsky.social · 1d

Methanol emission tracing ice chemistry and dust evolution in the TW Hya protoplanetary disk
https://arxiv.org/pdf/2510.04106
John D. Ilee, Catherine Walsh, Jenny C. Calahan.

https://arxiv.org/abs/2510.04106

arXiv abstract link

arxiv.org

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John Ilee @johnilee.bsky.social · 12d

Such a shame. He gave a really encouraging speech at our graduation (and I also had the honour of being tapped on the head with a pair of very old trousers by him!). RIP.

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Reposted by John Ilee

Sierra Grant @sierragrant.bsky.social · 19d

Today is a special paper day for me: for the first time we can do chemistry in a circumplanetary disk around a planetary-mass companion! Gabriele Cugno and I used JWST to tease out the signal of CT Cha b, finding a rich carbon chemistry (7 molecules + 1 isotopolog detected)! arxiv.org/abs/2509.15209

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Reposted by John Ilee

Matthew Kenworthy @mattkenworthy.bsky.social · 22d

A very cool result! Julo+ with a paper on “Stellar halo subtraction … with integral field spectroscopy… on the PDS70, HTLup, and YSES1 systems” showing that the YSES 1b #exoplanet has a lot of emission lines - H alpha , H beta, He I, Ca H and K triplets, Na in absorption… oh my! #astrodon ☄

Two spectra of the planet YSES 1b. The left hand spectrum shows a huge peak of Hydrogen alpha emission, and the right hand spectrum shows Calcium II triplet in emission, next to a fuzzy Sodium absorption feature.

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Reposted by John Ilee

Exoplanet Courier @exocourier.bsky.social · 26d

[2509.09450] Richard Teague et al.: A Radially Resolved Magnetic Field Threading the Disk of TW Hya. link

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Reposted by John Ilee

Matthew Kenworthy @mattkenworthy.bsky.social · 26d

My periodic reminder for #astrosci #astrodon #exoplanets Early Career Researchers to please, please, please have a simple web site with your current email address on it - rationale here: kenworthy.space/advice/

A pen sketch of a web page for an astronomer, showing name, email, optional phone number, and professional contact details, with a one sentence summary of their research and an ADS link.

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John Ilee @johnilee.bsky.social · 28d

Sending my apologies to the reviewer for this one… 😬

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Reposted by John Ilee

Dr Duncan Forgan @dh4gan.bsky.social · Aug 12

It is well within the power of journalists to simply stop interviewing this individual

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John Ilee @johnilee.bsky.social · Jul 17

I am a researcher in astronomy

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