Hannah Wakeford

@stellarplanet.bsky.social

1239 Followers 206 Following

Exoplanet scientist. Science communicator. Author. Podcaster. Miniature painter. Wife. Cat mum.

Me in my external gown. It has blue lines down down the front and silver and red hood
Nails painted light pink with bright blue French tips.
Text reads HD209458b cloud babies: Ariah, Finn, Forest Moon.
Meme showing cartoon shouting person with the words "Give me all the data"
Figure from Calamari et al. (2024, 2026) showing the Mg/Si bulk fraction versus the fraction of the oxygen inventory for the planet. The Mg/Si ratio comes from the star with HD209458b sitting in the regime where it would be expected that both Mg2SiO4 and MgSiO3 could be present at the same time while other hot Jupiters with silicate cloud detections tend to sit in the region most dominated by SiO2 cloud formation.
Spectrum of HD209458b measured from 5 to 12 microns with JWST MIRI. The plot shows wavelength versus transit depth. The data are shown for two different ways on selecting the "best" reduction pathway we call the 1-leaf and one combining the information from multiple valid reduction pathways in this case 4 paths to make the 4-leaf spectrum of the planet. We then use the same model to determine if they convey the same information and find that both models equally well fit the data.
left: a plot of the planet spectrum from 0.3 to 12 microns. The spectrum is fit with Mg2SiO4 clouds and Mg2SiO4+MgSiO3 clouds. The two spectral fits are offset to show them in the same plot against the data. Right: the modelled temperature-pressure profile of the atmosphere showing that the forward models cross the condensation curve of the two cloud species suggesting their presence modelled in our spectrum is physically motivated. We also show the PT profile from a complex 3D general circulation model of the atmosphere which predicted it to be colder than measured and our retrieved PT profiles which only go to the cold temperatures where the clouds form high in the atmosphere. The forward model PT profiles ground the detection despite the PT profile being unconstrained by the retrievals.
a plot of wavelength versus transit depth showing the full spectrum of HD209458b combining Hubble data from 0.3 to 1.6 microns, JWST NIRCam data from ~2 to 5 microns, and out new JWST MIRI data from 5 to 12 microns. The spectrum shows prominent absorption from H2O, CO2, with scattering towards the blue optical indicative of small particle scattering from clouds. The MIRI data shows the broad absorption due to magnesium silicate clouds. The right side shows the probability density retrieved for the pressure of the cloud and the radius of particles. A broad unconstrained distribution is shown is pale when just using the MIRI data alone, by including the short wavelength data the location and particle size of the cloud can be constrained.
Two plots showing wavelength (x) versus transit depth (y). Left: The measured planet spectrum with three models one for a cloud free atmosphere which is shown to deviate from the data structure significantly, two which include clouds of Mg2SiO4 or Mg2SiO4+MgSiO3 which both equally fit the data well. Right: the contribution of different species to the modelled atmosphere with a cloud of Mg2SiO4 where at short wavelengths the model is dominated by H2O absorption and at longer wavelengths the model is dominated by the cloud absorption.
Wavelength versus transit depth figure. The planet spectrum is shown as black points with vertical errorbars. Overlayed is the expected spectrum of different silicate absorption signatures which peak around 9 microns but have varying structures, peak amplitudes, and extents. The best fit species is in bold and matches to Mg2SiO4 sol-gel amorphous cloud particles.
This shows the final transmission spectrum of HD209458b measured with JWST MIRI LRS. The spectrum is from 5 to 12 microns. There is an orange spectrum which shows the 1-leaf result as a half gaussian (a vertically cut circle), on the other side is the gaussian mixture model of the 4-leaf spectrum. In many cases the 4-leaf spectrum shows a wider or shifted error profile compared to the 1-leaf spectrum.
the final rule-based tree-structure with uncle data at the top. The tree then splits in two with the number of groups to mask. Each branch then splits in two again with the amount of baseline to use. The four branch ends are related to the systematic model used such that long baselines require linear+exp fits while short baselines just require linear fits. This leaves four results, one at the end of each branch, that represent the potential spectra of the planet.
Diagram of the key steps considered in the MIRI/LRS Rule-based tree structure model for this dataset going from the uncal data to the final speci,j,k,.... At the nodes of the tree, branches are expanded for different reduction and analysis choices. Triple dots are used to indicate the continuation of the tree structure. The tree can be described as homogeneous or symmetric in that it can be thought of as a complete set of decisions with no dangling branches.
The high temperature cloud sequence. At around 700K high altitude clouds of hazes form with salts deeper and silicates deeper still. At 950K and above the hazes and salts evaporate and silicates become the top most cloud deck. At around 2000K the silicates evaporate and Aluminium oxides become the top most clouds in an atmosphere. From 950 - 2000K silicates dominate the cloud sequence.
blue sky with high and low clouds. Thick yellow arrows coming from the top show the incoming solar rays. Thinner yellow arrows bounce off the cloud tops or from the bottom of the image depicting reflected starlight. Thick red arrows come from the bottom of the image showing IR radiation which is absorbed or reflected by the clouds. Lower clouds are more effective at reflecting back to the bottom more IR radiation and emitting more IR radiation to space.
Terrarium in a large rectangular fish tank. The moss and gravel is made to look like the forest moon of Endor from Star Wars and a small model of an Ewok and R2D2 are in the foreground
Desk with spotlight lamp, microphone and camera set up for filming.
Large iron ship docked along Bristol Quay. The name Balmoral can be seen in yellow letters along the front
Ringberg castle in the snow with mountains in the background
snow falling over the forest viewed through a large two story double wide castle doorway
Looking out the left side of an airplane with the jet engine and wing visible. The view to the ground is clear but the view to the near horizon steadily gets whiter and whiter due to the observation at slant geometry through thin scattering particles in the atmosphere
Looking out over Bristol skyline with low lying white fog and bright blue sky above
The view of the Royal Astronomical Society from across the courtyard in the Royal Society of Chemistry
Small black cat siting on a box. They have a small cone around their neck to prevent them licking any wounds
Retrieved temperature of the planet's limb compared to GCMs from Kataria et al. (2016) showing that the limb does not equal the equilibrium temperature but is in line with predictions from complex 3D modelling.
Two exoplanet spectra with models fit by increasing the amount of data used by 0.1 micron increments. Demonstrating that near-IR data alone cannot predict the cloud properties accurately as the models do not fit the data.
Information content change for 13/14 planets in the study. Showing a gain in information when shorter wavelength data is included in the fit. The bottom panel shows the cloud parameters broken down into the four specific components.
14 planetary transmission (absorption) spectra with three model fits. Orange - just considering data longword of 1.1 microns. Blue considering data long of 0.6 microns. Purple considering data long of 0.3 microns. With added data tighter constraints on the model can be seen.
Me firing holding up the Osiris Rex launch pass at the cape in florida
Blue super moon positioned to be on the end of the nose on a shark statue outside the aquarium. A group of over 60 astronomers are gathered below
Small black cat drooped over a lap with beans on show