No yeah, it’s not just you… TAing for two courses this semester and students are routinely failing very easy questions in the exams. It’s brutal

Congrats!!!!

Congrats!!!

Radii versus mass for sample.

Payel's second paper finds indirect evidence for water in nine hot super-Earths around M-dwarf stars! Tune in to find out more.
arxiv.org/pdf/2604.07447

Thank you!!

Had the first (mostly) chronic pain free day in a while 😎

(This was my MSc thesis paper, and I'm glad it's finally out!! Thank you to everyone on the NIRPS team for being so helpful during the process of writing this paper!!) 13/13

In short:
- We measured the masses of several rocky planets around M dwarfs
- We compare those planets to their host stars' abundances
- The planets are underdense compared to what their host stars imply, which we interpret as being due to the presence of water inside these planets!!

12/

these are REALLY hot planets, but we can't say for sure. Finally, we do a sanity check for future observers -- YOU DON'T NEED SO MUCH TELESCOPE TIME TO EXPAND THIS RESULT! Just get a larger planet sample with less precise masses instead, it's WAY more efficient than getting 200 RVs per target. 11/

That's what we're seeing here! We find that, surprisingly, you don't need a LOT of water to explain the differences between the planet and the star. In fact, water making up ~1% of the planet's mass is enough to explain it!

We think any water would likely be sequestered inside the planet, since 10/

The core mass fractions of my planets, both as inferred from the planet's mass/radius and from their host stars' abundances. You can see that on a population level, the planets have consistently smaller core mass fractions (read: are less dense) than their host stars would imply, though due to the uncertainties involved it's hard to make that claim about any one planet.

This!! It sure looks like our planets have less massive cores (and are thus less dense) than their host stars imply... (and we show that they do, statistically!)

Earlier, we said if these planets are chronically underdense, that has to be because of something light making up part of the planet. 9/

From there, we can calculate the fraction of the planet's mass that's in the core through some modeling of the planet's interior. We can then compare those to the "equivalent" core mass fractions that we get if the planet just had the same elemental abundances as the star.

We get... 8/

A plot showing the fit to a single spectral line (an iron line of HD 260655), and our model fitting to it the best it can. (Sadly, most spectral lines are NOT nearly this clean!)

We ALSO use these data to precisely measure abundances of these planets' host stars from near-infrared spectra, using a new routine developed by my friend and collaborator Nicole Gromek (paper coming pretty soon!) Getting abundances is REALLY difficult for these cool stars, but we do our best! 7/

A plot of the RVs of GJ 1132 (b on top, c on bottom) as a function of orbital phase. Look at how precise our measurements are!

A plot of the RVs of GJ 1252 (b on top, (c) on bottom) as a function of orbital phase. Look at how precise our measurements are!

A plot of the RVs of LTT 3780 (b on top, c on bottom) as a function of orbital phase. Look at how precise our measurements are!

them to their host stars! We got a WHOLE bunch of telescope time on the NIRPS spectrograph to precisely measure the masses of 3 hot rocky super-Earths (and take another 6 planet masses from other studies because we took up enough telescope time already 😭) Really, check out these RV curves! 6/

these stars tend to be LESS dense than their host stars would imply? Well, then, there has to be some sort of light material that's making up a substantial chunk of these planets...

like water 👀

For this work, we precisely measure masses of a bunch of rocky planets around M dwarfs, and compare 5/

see that planets with more iron are going to have a bigger core (and be more dense). Thus, stars with more iron (compared to silicates that form rock) should host planets with more iron (and thus have larger cores, and be denser)!

But what if we DON'T see that? What if we see that planets around 4/

The answer is by comparing rocky planets around these M dwarfs to their host stars! See, planets form out of the same cloud of material as their stars, so they ~should~ have similar elemental abundances as their stars. Since planets should be made of just an iron core and a rocky mantle, we can 3/

A figure from Wanderley et al. (2025), showing that demographics of M dwarf exoplanets might be consistent with something called gas-poor formation (read: water-rich formation) rather than other formation theories. We want more evidence than this, though!

form via something called "water-rich formation", where their planets form with, well, a lot of water vs. around bigger stars.

This is what simulations predict, and on a demographics level we sort of see the signs of this. But how can we get more concrete observational evidence of this? 2/

Paper day!!! 🎉 arxiv.org/abs/2604.07447 ⬇️ #exoplanets #astronomy

It all starts with planets around really small stars (M dwarfs). There's some evidence that planets around these stars form fundamentally differently than around stars like our Sun. We think that planets around these stars may 1/

Yeah, he's got hustle, he's playable as a third-stringer, that's enough to put him ahead of your average 55th pick tbh

Sriracha and Frank's, need two on opposite ends of the spectrum

guy forgets to get his ez-pass before leaving port, rolls his eyes, steers into the cash only lane, begins feeding eight million quarters into the slot one by one

the amount of packages that have been delivered not to my apartment (despite clear directions & open air access), or even to my mailbox on the other side of the building, but to the pizza place on the first floor of my building instead

The provincial riding Poilievre lives in just flipped from CPC to LPC in a by-election today, despite it being a very conservative district

All 3 professors I did work with in undergrad said this to me when I was applying to programs, it's bleak

I did! I even used EC-1118, which is supposed to power through everything (including that cursed red-40 mead I once tried to make).

The EC-1118 eventually managed to chew through the juice with potassium sorbate, but it struggled enough I'd really have to recommend finding some without

Make sure there's no potassium sorbate in the juice! It'll make the yeast stall like a mfer. I've made this mistake before :(

(not JWST, to clarify, but still)

My group had 4 straight proposals accepted, changing nothing but target selection, and then the 5th nearly-identical one was rejected flat out and given 4th quartile. Sometimes these are just stochastic processes

Skeleton squatting with text that says "My body turns submitted JWST proposals into rejections"

Happy Friday everyone! 🔭☄️