Tessera
Folgen

Duncan Christie

@astroduncan.bsky.social

Astrophysicist. Postdoctoral researcher at the MPIA. Exoplanet atmospheres. (he/him/his) www.duncanchristie.net

127 Posts330 Follower119 Folgt
Duncan Christie@astroduncan.bsky.social · 7d ago

The only time a 15, 20, 25, etc., page letter is reasonable is when you're writing to your beloved who you haven't seen in years, and they are separated from you by a long, perilous journey across an unforgiving sea.

Evert Nasedkin@evertnasedkin.bsky.social · 7d ago

🔭 New paper day! 🪐 This time from Merle Schrader, a PhD student in the brown dwarf group at Trinity College Dublin. Today, they're publishing a fresh look at SIMP-0136, using principal component analysis, identifying the mechanisms driving its atmospheric variability. arxiv.org/abs/2607.26182

The JWST weather report: Unravelling the atmospheric variability of isolated worlds using principal component analysis

Brown dwarf variability directly probes atmospheric dynamics beyond the Solar System, and recent JWST time-resolved spectroscopy has opened a new window into these processes. Principal component analy...

arxiv.org

Harrison Nicholls@nichollsh.bsky.social · last wk.

New paper on arXiv today! On the efficacy of using novel Bayesian machine learning to dispatch 'expensive' forward models of planetary evolution. This connects with #PLATO ageing and can help solve degeneracies in current static-retrieval approaches which treat #exoplanets as snapshots.

Constraining the lives and times of exoplanets through evolutionary Bayesian retrievals

Static retrieval frameworks are leading tools for interpreting exoplanet observations, yet time-independent modelling leaves them prone to degeneracy and unable to resolve exoplanets' histories. The c...

arxiv.org

Duncan Christie@astroduncan.bsky.social · last wk.

I have posted multiple times in the past how Canadian visitor visa processing times when applying from Germany, Austria, and the UK were on the order of 300 days, making conference travel to Canada difficult for some researchers in those countries. They are now all listed as being under 35 days. 🎉

Duncan Christie@astroduncan.bsky.social · 3w ago

The Exoplanets VI conference in Porto was really well organized (credit to the LOC), but the lack of train access was disappointing. Exoplanets VIII, slated to be in Tenerife, will likely have everyone flying as well, as I doubt many will take the 30+ hour ferry ride. #exoplanets

Erin M. May, PhD@astronomay.bsky.social · 4w ago

New Paper Day! JHU Grad Student @spschmidt.bsky.social 's paper on the ultra hot Jupiter KELT-7b includes a new method to mitigate charge migration in JWST NIR detectors, and finds a metal rich atmosphere for KELT-7b relative to its metal rich star 🪐⭐ arxiv.org/abs/2607.06708 #Exoplanets 🧪🔭

Mitigating Charge Migration in JWST NIRISS Reveals That KELT-7 b is a Metal-enriched Ultra-hot Jupiter Orbiting a Young Metal-rich Star

We present the first panchromatic JWST transmission spectrum of an ultra-hot Jupiter, combining NIRISS and NIRSpec observations to constrain KELT-7\,b's atmospheric properties. We show evidence for ch...

arxiv.org

Linn Boldt-Christmas@nplinnspace.bsky.social · last mo.

A very merry yee-haw to all horse girls & cowboys (gender neutral: horse cows?) attending #HoRS3S in Granada this week! I've sadly ended up unable to attend IRL this year, but am sending my best in the form of a poster that'll be up in my absence on #exoplanet WASP-107 b 🔭🤠💖🐎🧪 Have a fun week y'all!

Don’t throw away your rubbish ground-based transit data (yet)! -- A cautionary tale starring warm super-puff WASP-107 b and VLT The problem: Ground-based transmission spectroscopy observations have seen remarkable success in characterising hot Jupiter exoplanets in the last decade with increasingly high detail, and our hope is to eventually characterise smaller, cooler exoplanets similarly – one day, even Earth-like targets. To get there, we have to explore what shortcomings exist in our current observational capabilities and methodology by exploring an ”in-between” target: the neither-temperate-nor-hot Neptune-sized WASP 107-b (Teq ≈ 740K). Method: WASP-107 b is already well-studied from space, and thus a good playground for assessing the quality of our ground-based approaches. It is observationally favourable in some ways (e.g. good scale height) but more challenging in others (e.g. cloudy, cooler Teq), making it a good case study for our tried-and-tested techniques like cross-correlation. A number of molecular species had already been detected by JWST, but could we do it from the ground? By using a combination of real and simulated data, we could explore what aspects of traditional methods perform well for these challenging targets, and which need a rethink. We found that for cooler and cloudier targets like WASP-107 b, the amount of signal that one can reasonably expect is unfortunately very low. Several factors can compound and effectively create scenarios where there is simply not enough signal to reach detections of S/N ≥ 5, even if everything is done ”correctly”. What looks like bad data might not be bad, just… as good as we can get, for now!
Duncan Christie@astroduncan.bsky.social · last mo.

Aniket Sanghi did a 'cold open' to his #Exoplanets6 talk, showing his title slide and introducing himself after a broad introduction to the science. I don't know if I would want it to become the norm, but it was very well done and was a nice break from the usual talk structure.

Duncan Christie@astroduncan.bsky.social · last mo.

MPIA PhD student Angelique Kahle has a very cool paper out today looking at everyone's favourite ultra-hot Jupiter, WASP-121b. Angelique is giving a talk on the results next Monday at Exoplanets VI, as well. #exoplanets arxiv.org/abs/2606.21855

The panchromatic JWST dayside spectrum of WASP-121 b reveals a refractory-rich formation

One path to understand how planets form is to link their present-day atmospheric composition to predictions from planet formation models. For the hottest planets, the abundances of refractory species ...

arxiv.org

Duncan Christie@astroduncan.bsky.social · 2mo ago

We need to stop shielding executives and developers at X and xAI from liability by using language like "Grok AI broke Canada's laws", as if Grok has any sort of agency. globalnews.ca/news/1189968...

Grok AI broke Canada’s laws, created 6K sexual deepfakes per hour: probe - National | Globalnews.ca

Philippe Dufresne launched an investigation in January to examine the proliferation of sexualized deepfakes created by Grok and shared on the X social media platform.

globalnews.ca