We observed the habitable zone planet TRAPPIST-1e with JWST to search for an atmosphere.

You've seen the headlines, now let's dive into the science! 🧪

THREAD (1/N)

#Exoplanets 🔭

Update on the atmosphere vs no atmosphere debate for TRAPPIST-1 b and c -- here's a nice and (IMO) conclusive result from Gillon and Ducrot et al.: no thick atmosphere on either planet. arxiv.org/pdf/2509.02128

Happy to share the first paper from the SPACE Program, led by my student Angelique Kahle! she observed a hot little sub-Neptune, HD 86226c (Rp = 2.3 Re; equilibrium temp = 1300 K). arxiv.org/pdf/2507.13439

The spectrum is *really* flat ! here's the amplitude compared to other gaseous planets.

My paper with Tom Evans-Soma and Nathan Mayne on magnetic drag models is now accepted and up on the arXiv. For a quick summary, look at the PDF of my Exoclimes poster that I shared last week.

www.arxiv.org/abs/2507.08511

Just finished answering questions from my 10pm (local time) Exoclimes talk #ExoclimesVII — been following sessions into the night all week due to Canada time zone.

Thanks to the LOC for enabling live audio & remote presentation.‬ It eased the pain of missing in-person due to visa issues.

I recommend giving this paper by @jiachenliu.bsky.social, @astroduncan.bsky.social, and Jun Yang a close read: arxiv.org/abs/2506.23891. Sub-Neptunes like K2-18b lie in an interesting regime where both the radiative feedback and mixing of chemical tracers is important, I’m looking forward to Part 2!

Jiachen Liu (@jiachenliu.bsky.social) has a very interesting paper out where she looks at the dynamics of K2-18b, modelled as a mini-Neptune.

www.arxiv.org/abs/2506.23891

The detailed analysis of chemical structures will be presented in Part II, which is coming soon. Stay tuned!

My new paper, co-authored with Duncan Christie and Jun Yang, on 3D chemical kinetics simulations of K2-18b has been accepted by MNRAS!
This is Part I of a series. In Part I, we examine the planet's atmospheric dynamics and its impact on the transport of passive tracers.
arxiv.org/abs/2506.23891

Can't agree more!

"The possible elimination of the lab, called GFDL, in concert with potential cuts to other NOAA operations, threatens irreparable harm not only to global understanding of climate change and long-range scenarios for the planet but to the country’s safety, competitiveness and national security."

𝗡𝗼, 𝗮 𝗯𝗶𝗼𝘀𝗶𝗴𝗻𝗮𝘁𝘂𝗿𝗲 𝘄𝗮𝘀 𝗻𝗼𝘁 𝗷𝘂𝘀𝘁 𝗱𝗲𝘁𝗲𝗰𝘁𝗲𝗱 𝗶𝗻 𝗞𝟮-𝟭𝟴𝗯'𝘀 𝗮𝘁𝗺𝗼𝘀𝗽𝗵𝗲𝗿𝗲.

K2-18b is back in the news, now with a bold claim that biosignature molecules (DMS and/or DMDS) have been 'detected at 3σ'.

Most exoplanet astronomers are extremely sceptical about these claims, let's see why (1/n).

🔭🧪🪐 #exoplanet

An astonishing headline reporting on new observations from a team led to Nikku Madhusudhan claims they’ve found ‘hints of life’ on a planet orbiting a dwarf star some 124 light years away. What’s going on? (1/n) www.bbc.co.uk/news/article... 🔭 🧪

Shared some (highly skeptical) thoughts on today’s “habitable planet” #K218b news. Thank you @npr.org for the responsible reporting on this topic!

In addition, we find that the surface inversion (SIV, surface cooler than its adjacent air) is also a distinct phenomenon in the hothouse climate.
This schematic shows how these two kinds of inversions form.

Near-surface atmospheric (NAIV) inversion is a phenomenon reported in previous hothouse climate simulation papers (e.g., Wordsworth & Pierrehumbert, 2013; Wolf & Toon, 2015), but its formation mechanisms remain unclear. In this paper we employ a hierarchy of models to investigate its mechanisms.

The hothouse climate may occur following a Snowball Earth event in Earth’s history, on a future Earth under the brightening Sun, or on terrestrial planets near the inner edge of the habitable zone.

My new paper with Feng Ding and Jun Yang has been accepted at ApJ: arxiv.org/abs/2504.05233.

In this study, we find that lower-tropospheric radiative heating is necessary but not independently sufficient to form the NAIV. Instead, the dynamic heating induced by large-scale subsidence is essential.