iiinova — where your digital self keeps evolving

Andrew Sellek @andrewsellek.bsky.social · 01/09/2026

New academic year, new postdoc position!

Andrew Sellek @andrewsellek.bsky.social · 15/10/2025

With just under 12 hours to go, here's how JWST Cycle 5 proposal submissions are progressing according to our sampling of the star and planet formation people here in Leiden! We're well past the 1000 mark for the year (and 10,000 across all years!) now, but where will we end up?

The image shows a plot of the ID number of proposals submitted to JWST with the date of submission plotted from left to right. Each is marked as a green triangle and together they form an upwards curve showing roughly exponential growth. A horizontal yellow line below the data shows the minimum start point based on previously accepted proposals.

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Reposted by Andrew Sellek

Sierra Grant @sierragrant.bsky.social · 07/08/2025

Another MINDS JWST paper! We explore the stark transition from H2O-dominated spectra in Sun-like systems to the carbon-rich chemistry seen for low-mass objects. We don't know exactly what is driving this trend, but we explore the possibilities that may be acting in concert. arxiv.org/pdf/2508.04692

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Reposted by Andrew Sellek

Sierra Grant @sierragrant.bsky.social · 05/08/2025

New MINDS paper from Nicolas Kurtovic, focused on binary systems. Spectra, extended emission, variability, multi-observatory analysis -- there's something for everyone! arxiv.org/pdf/2508.02576

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Andrew Sellek @andrewsellek.bsky.social · 02/05/2025

Based on a recent workshop series, hosted by Giovanni Rosotti, @cfmanara.bsky.social, Tom Haworth, and Megan Reiter, we summarised in @ojastro.bsky.social the latest results on a growing topic in protoplanetary discs - the role of external irradiation - and how we hope to answer the open questions:

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Reposted by Andrew Sellek

Nienke van der Marel @nienkemarel.bsky.social · 26/03/2025

Super proud of my PhD student Osmar who discovered that the so-called 'compact disks' around young stars are REALLY REALLY small! Look at the full sample of Lupus disks, observed at 30 mas resolution with ALMA.

astronomie.nl

Protoplanetary discs are much smaller than previously thought

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Reposted by Andrew Sellek

Dr Jared Jeyaretnam ⚛️🧪 @jaredjeya.github.io · 11/02/2025

I used to do science outreach with a group called CHaOS (see link!). We’d often ask kids to draw a scientist at the start and end of our sessions. They’d often go from drawing an Einstein-esque mad scientist, to someone who looked at lot like themselves (or perhaps one of us) 😊 #AcademicChatter

chaosscience.org.uk

CHaOS – Hands-On Science

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Reposted by Andrew Sellek

Ilaria Pascucci @pascucci.bsky.social · 21/01/2025

Congrats to my student Chengyan Xie 🎉 for his work analyzing Spitzer+JWST data on T Cha! 🌟 He uncovered dramatic changes in the star’s disk—inner disk eroding in an outburst, reshaping IR emission. This object deserves follow-up! 🪐✨ #JWST iopscience.iop.org/article/10.3...

iopscience.iop.org

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Andrew Sellek @andrewsellek.bsky.social · 18/12/2024

The latest protoplanetary disk study by the MINDS collaboration using JWST-MIRI is out now! arxiv.org/abs/2412.127... Led by Leiden PhD student Marissa Vlasblom, it focusses on CX Tau, a disk for which the dust emission is much more compact than gas, suggesting dust grains have drifted inwards. 1/4

The spectrum of CX Tau showing how bright the disc emission is as a function of infrared wavelength. The disc gets brighter going from shorter wavelengths on the left to longer wavelenghts on the right, with a large bump at 10 micron due to Silicate dust grains. On top of the smooth continuum are a few weak lines, the most prominent ones being due to atoms such as HI and Ne or CO2. Inset panels show zoom-ins that demonstrate the presence of weak water features.

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Reposted by Andrew Sellek

Nienke van der Marel @nienkemarel.bsky.social · 12/12/2024

JWST MIRI has revealed that disks around very low-mass stars are hydrocarbon-rich but water-poor in the inner disk (Aditya Arabhavi). Result of dust traps? What are the implications for planets forming here? #NOVA25

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Andrew Sellek @andrewsellek.bsky.social · 04/12/2024

It's paper day! arxiv.org/abs/2412.01895 JWST is studying the molecular contents of the inner regions of protoplanetary discs in unprecented detail, and they turn out to be very varied. Some discs, eg DR Tau, are dominated by emission from water, others, eg GW Lup, are dominated by CO2. But why? 1/6

Two panels showing the JWST Spectrum of DR Tau (a protoplanetary disc) and its decomposition into different molecules as a function of wavelength, from Temmink et al. (2024a). The spectrum shows many sharp spikes corresponding to bright emission lines of water, with some broader underlying variations. Models of emission of different molecules are plotted in different colours at the bottom and their sum as the shaded red region at the top, which is overlaid on the data in black.

Two plots showing the JWST Spectrum of GW Lup (a protoplanetary disc) and its decomposition into different molecules as a function of wavelength, from Grant et al. (2023). The clearest feature is a broad triangular shaped bump at ~15 micron resulting from CO2, with some fainter surrounding spikes mostly due to water or CO2. Models of emission of different molecules are plotted in different colours at the bottom and their sum as the shaded red region at the top, which is overlaid on the data in black.

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