@JuliaVSeidel High-res / SNR observations allow resolving sub-features! So instead of taking the whole transit now, we can also just take parts of it and resolve it in time. If you do that, you see that the sub feature comes from egress suggesting dynamics in the form of an equatorial jet. So what those ingress show us?
Does it confirm the jet, suggest radial winds or is it a global day to nightside wind? We‘ll friends, I am not allowed to share it with you. Stay tuned! 🤫🚫 #ExSSV
We‘re back with #atmospheres and #interiors, kicked off by Stefan Pelletier on a gas giant planet that formed with more ices than rocks.
Stefan reminds us that back in the days we did not think we would be able to understand the composition of stars, but here we are, studying planetary atmospheres. Though forming planets is more complex because so many mechanisms contribute to the end product.
Nowadays, we can point at Jupiter + study its composition, right? No, we only got volatiles! #ExSSV
For forming planets, we‘ve got three components: Gas, volatiles, refractories. Jupiter only got the first two.
This brings us the ultra-hot Jupiter opportunity: our Jupiter is cloudy, while hot Jupiters let us glimpse into Jupiter-atmospheres and search for refractories and volatiles.
Using retrievals, they find that volatiles are super-solar, and the ice to rock ratio is super solar. So where did it form? Two scenarios are consistent, with enriched CO gas or solids #ExSSV
Next up, we‘ve got Louis-Philippe Coulombe talking a reflected light and thermal emission phase curve of an exo-Neptune.
Depending on the wavelength, we probe different chemistry, temperature, etc. regimes in the atmospheres of planets, see eg Jupiter. Often we need to observe at least twice or we just ignore reflected light, BUT #JWST can do both!
They looked at the full phase curve of the planet LTT 9779 b, sitting in the Neptune Desert. 🏜️
We kick off the session with Tiffany Kataria on assessing #conditions for the origin of #life on #exoplanet. For Tiffany, the origin of life is from geophysics to biophysics and important - habitable doesn’t mean inhabited and the origin of life is a way to rule out these false positives. #ExSSV
We’re back with a session on planets around white dwarfs 🪐
Ryan MacDonald reminds us that in a very long time this will be the fate of our sun too. Jupiter and Saturn will probably fine but closer in… nah likely not.
This is basically what we can test by looking at white dwarf planetary systems. Killing planets in this way means there are polluted white dwarfs with planetary material in their stellar atmosphere. But for the ones that survive we can do a study of what could be.
This planet cannot have been where it is today, so it went on a journey after the death of its star: rapid spiralling inwards or a high-eccentricity migration. But we don’t know which one happened.
This is where #JWST comes in. But little me cannot share more 🚫🤫Stay tuned! #ExSSV
The next talk is by Andrew Vanderburg on #MEOW: a survey targeting white dwarf systems to study the prognosis of the solar system.
Mars might survive, but be roasted. The smaller gravity after the red giant phase will push the orbits further out. See pictures for a graphics.
Combining data from TESS and JWST, they’ve found one close-in TESS planet around a WD, and even after searching 10000 more, they cannot find another one; so this is rare!
Next up, we’ve got Sihao Cheng on occurrence rates of giant planets around B stars.
It is difficult to discover planets around massive stars, so our knowledge of planets around them is very limited. A way to do is to study white dwarfs as dependents of these massive stars.
In some infrared bands, a planet around a white dwarf may actually be brighter than the white dwarf itself, which is excellent for direct imaging. Especially for young systems, this is the case. #ExSSV
While this was an idea already 15 years ago, instrumentation has advanced significantly. They checked plenty of systems and found one candidate with colour excess. This candidate will be observed with #JWST (hopefully) soon.
Ground-based spectra show that the host is a fast-rotating WD that used to be a massive star. Future observations will tell what we’re looking at! #ExSSV
For the last talk of today, we’ve got Tim Cunningham on accreted planetary material determined from #xray observations.
Tim starts with the #exoplanet#HR diagram and points out polluted white dwarfs. Roughly 25-50% of the WD we know show metal pollution. This is expected to be happening when the star dies and kills its planetary system + then accretes the planetary material.
The accretion rates depend on the atmospheric models of WDs. #ExSSV
One can study the accretion rate (and therefore the assumptions for the models) using X-rays, which they did for G29-38. But more is needed & coming 🤫🚫 No sharing anymore, Tim said no 🤓 Stay tuned #ExSSV
We’re back with#formation and #demographics this morning starting with Charles Law on embedded planets.
Charles stresses how much #ALMA has revolutionised the field providing a wonderful pictures of discs. Nevertheless, resolving planets embedded in these discs is pretty hard. But chemistry is our saviour, making signatures of the planet observable with #ALMA.
We start with the disc HD 169143 b - funny I worked with data from this disc for my bachelor’s thesis.#ExSSV
In this disc, there is a protoplanet! - so a baby planet 👶 🪐 and they trace it ALMA data and chemistry, note the asymmetry in the emission due to the planet. They put together SiS and SO: SiS appears blueshifted.
In addition, they also detect CO (12/13). Let’s put it all together!
The detection of SiS indicates shocks, and outflow of the planet because of the observed shift.
Take away: Si and S bearing molecules provide a new way for us to study protoplanets. More to come!! #ExSSV
Next up, we’ve got Kiersten Boley on the first evidence of the metallicity cliff in the formation of super-Earths.
The first stars were metal poor, so there were not enough metals to form planets via core accretion. So the question comes up: when did we start forming planets?
Already back in 1996, after finding 4 planets, people started doing statistics ;) in particular looking at how metallicity links to #planet#formation.
Super-Earths show weak trends with metallicity, though note that we’re still limited by not looking around “metal-poor” hosts.
They constructed a sample to determine occurrence rates around “metal-poor”, fairly bright FGK stars. From K2&Kepler, they expected 68 super-Earths at metallicity below -0.5 met. But they found none!
What does that mean? There is evidence for a metallicity cliff around -0.31 suggesting that this affects planet formation #ExSSV
Next up, we’ve got Casey Brinkman on rocky planet composition and the (non)-dependency on stellar abundances.
The structure of a rocky planet can be oversimplified as an iron core + rock. This allows to estimate the core mass fraction and from there tells us about the planet formation conditions.
Previous studies don’t agree on the correlation between star and planet, so they created their own sample of planets determining the CMF.
Metal poor => small CMF.
Metal rich => scattered CMF #ExSSV
Depending on the fitting algorithm, they find a steep line, meaning that there is a depletion/enrichment for planets in comparison to their host stars.
Nevertheless, they don’t find strong evidence for a correlation between host star and planet composition #ExSSV
Next up, we’ve got Kristo Ment talking about planet occurrences for mid-to-late M dwarfs from TESS.
you may find this as surprising as I do, but M dwarfs are the most common stars!
Let’s talk #demographics: despite having smaller protoplanetary discs, (early) M dwarfs seem to be forming more planets than others.
In Kristo’s work, they study late M dwarfs to see if this trend continues and what the radius mass relation looks like. There are 7 detected planets in this sample #ExSSV
We’re back after coffee, and jump right into star-planet interaction with Babatunde Akinsanmi talking to us about the tidal deformation and atmosphere of WASP-12 b.
WASP-12 b is one of the ultra-hot Jupiter orbiting close to the Roche limit, being tidally deformed by the host star.
One can measure the tidal deformation with light curves because the shape affects the shape of the curve.
Also, the phase-curve varies! This is super cool 🥹
Next up, we’ve got Maggie Thompson on constraints on masses and compositions of rocky exoplanet atmospheres.
How do rocky planets form their atmospheres? There are different ways: primary atmospheres, secondary or even hybrid atmospheres.
To figure that out, we need to know about the solubility of species in magma oceans. Maggie tells us about her study of H2 solubility because it could be that Earth got its water through H2 + magma reaction.
Here are some first results for TRAPPIST-1 e. The solubility has quite an effect on the atmospheric composition 🤯 #lava world people: this is for you. Include solubilities thanks.