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William Thompson

@wrtastro.bsky.social
1.1K followers 355 following 121 posts

Herzberg Instrument Science Fellow at the National Research Council in Victoria, Canada. Imaging exoplanets and writing #JuliaLang tools.

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William Thompson @wrtastro.bsky.social · 09/12/2025
SPIDERS is installed on the Subaru Naysmith platform and we got first fringes on from the upstream AO system. Next step, a real star! Huge thanks to Subaru, NAOJ, and the SCExAO teams for accommodating us. #exoplanets #instrumentation
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William Thompson @wrtastro.bsky.social · 18/10/2025
SPIDERS is out of the clean room and almost ready to ship — it’s really happening! #instrumentation #exoplanets
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William Thompson @wrtastro.bsky.social · 29/09/2025
Paper accepted to AJ! 🥳 Updated preprint coming to an arxiv server near you.
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William Thompson @wrtastro.bsky.social · 02/09/2025
First day as a Plaskett Fellow 😎
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William Thompson @wrtastro.bsky.social · 29/08/2025
Last day as a Herzberg fellow 🥲
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William Thompson @wrtastro.bsky.social · 16/08/2025
To make it work, I had to pass “--overcommit” Story of my life…
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William Thompson @wrtastro.bsky.social · 15/08/2025
#exoplanets As we speak, Octofitter is running on nearly 20,000 cores 😅 maybe a record for most exoplanet orbit fits run in parallel?
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William Thompson @wrtastro.bsky.social · 15/07/2025
Octofitter v7, now released! This release overhauls the modelling syntax and add some powerful new capabilities for advanced users. [1/4] (Octofitter is a package for Bayesian modelling of exoplanet orbits)
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Brett Morris @brettmorr.is · 14/07/2025
The brightest star in Scorpius, Antares, is nearing the end of its 15 million year life. It's so large that the orbits of Mercury, Venus, Earth and Mars would be inside the star. 🔭🧪 Pilate et al. published brightness maps of the star, showing gigantic convective cells. arxiv.org/abs/2507.08614
Relative brightness maps of Antares over the course of a year, showing the changing brightness and shapes of convective cells in the stellar photosphere.
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William Thompson @wrtastro.bsky.social · 12/07/2025
Direct imagers, what is your expectation for how speckles behave at high spectral resolution? Do they vary smoothly with wavelength? We have an R11,000 cube at 10^-7 contrast to share soon, but I’m curious to hear people’s expectations first #instrumentation #exoplanets.
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William Thompson @wrtastro.bsky.social · 10/07/2025
Position of Epsilon Eridani b in-front/behind the star, and phase angle over time for those interested. Updated pre-print should be ready soon! 🔭 #exoplanets
a plot of a planet's position vs the star in 2D indicated as coloured lines. The line colour goes towards red or blue as the planet is in front of the star or behind. It is blue on the left, red on the right, and green, indicating 0, at the top and bottom. The separation is about 1000 milliarcseconds left or right increasing to about 1300 at top or bottom, creating an oval.
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William Thompson @wrtastro.bsky.social · 06/07/2025
There’s something very special about the gulf islands 🏝️
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William Thompson @wrtastro.bsky.social · 03/07/2025
Our JWST DDT was accepted 🥳
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Jayke Samson Nguyen @jayke.io · 02/07/2025
Found some beautiful Neptune data digging through the Keck Observatory Archives! The pole isn't nearly as visible now as it was back in 2002.
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William Thompson @wrtastro.bsky.social · 03/06/2025
I was honoured today to give the Plaskett medal award talk to open this years Canadian Astronomical Society meeting in Halifax! Great to share our work on #exoplanets imaging and modelling 🔭
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Heidi B. Hammel @hbhammel.bsky.social · 27/05/2025
Astonishing new videos of the Sun show coronal "rain" in (pink-tinted) hydrogen-alpha light. Obtained with advanced adaptive optics research supported by NSF, the National Solar Observatory, and New Jersey Institute of Technology. Details and more videos in the link in the first comment below.
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William Thompson @wrtastro.bsky.social · 22/05/2025
Octofitter v6 just released! 🐙 * Overhauled Hipparcos / Gaia modelling * Multi-planet epicycle approximation * Include astrometric jitter, north angle, and plate-scale uncertainties * Dynamical priors (prevent crossing) * Celerite gaussian processes Much more! (fig. credit in reply) #exoplanets 🔭
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Aniket Sanghi @astroaniket.bsky.social · 17/05/2025
Check out our short update on JWST mid-infrared observations of the closest Sun-like star, Alpha Centauri A! iopscience.iop.org/article/10.3...
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Paul Byrne @theplanetaryguy.com · 07/05/2025
Credit: Jason Wang/William Thompson/Christian Marois/Quinn Konopacky Access the video and related data here: jasonwang.space/orbits.html
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William Thompson @wrtastro.bsky.social · 29/04/2025
Recent images from our SPIDERS pathfinder instrument demonstrating the self-coherent camera--next generation tech for direct imaging of exoplanets! We use a special coronagraph to interfere the starlight with itself, like a classic double slit experiment... [1/3] 🔭 #Instrumentation #exoplanets
fringed image of star behind coronagraph unfringed image of star behind coronagraph
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William Thompson @wrtastro.bsky.social · 27/03/2025
Thank you @fherwig.bsky.social!
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Physics & Astronomy at UVic @phys-astro-uvic.bsky.social · 26/03/2025
Congratulations to Dr. William Thompson '23, of ARC and NRC-Herzberg, who was named as the recipient of the 2025 CASCA Plaskett Medal and the NRC Herzberg Plaskett Fellowship for Most Outstanding Doctoral Thesis in Astronomy or Astrophysics 🎉 #UVic #UVicScience #CASCA #ARC #NRCHerzberg #Astronomy
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William Thompson @wrtastro.bsky.social · 25/03/2025
I learned today that am being awarded the J.S. Plaskett medal for most outstanding doctoral thesis in astronomy in Canada. Thank you @casca.ca.web.brid.gy, and my committee for the nomination! 🔭
CASCA is pleased to announce Dr. William Thompson as the 2025 recipient of the Plaskett Medal for the most outstanding doctoral thesis in astronomy or astrophysics. 

Dr. Thompson’s thesis, defended at the University of Victoria in 2023 under the direction of Profs. Falk Herwig and Christian Marois, is entitled, “Lights in Motion: Observing Nearby Planets with Imaging, Wavefront Sensing, Orbital Detection, and Spectroscopy”. The title hints at the breadth of the research described within Dr. Thompson’s thesis work, including developing new computational methods to analyze angular differential imaging observations and employing these methods to discover a new candidate exoplanet around HR 8799; developing the first multi-technique exoplanet finding code that can incorporate radial velocity, astrometry and high-contrast imaging data; carrying out both simulation and laboratory tests of two new techniques for exoplanet imaging; and more. The thesis external examiner notes that, “it is the combination of innovative thinking, rigorous simulation and laboratory testbed results which make the work so impressive.” The software developed as part of Dr. Thompson’s thesis research is publicly available and is already being used by other exoplanet researchers, and his instrumentation development work provides first steps toward possible hardware contributions to the Habitable Worlds Observatory.  CASCA is delighted to recognize Dr. Thompson for these outstanding contributions.La CASCA a le plaisir d’annoncer que le M William Thompson, Ph. D., est le lauréat de la médaille J.S. Plaskett 2025 pour la thèse de doctorat la plus remarquable en astronomie ou en astrophysique. 


La thèse du M Thompson, Ph. D., soutenue à l'Université de Victoria en 2023 sous la direction des Profs. Falk Herwig et Christian Marois, est intitulée « Lumières en mouvement : observation de planètes proches à l'aide de l'imagerie, de la détection de front d'onde, de la détection orbitale et de la spectroscopie ». Le titre fait allusion à l'ampleur de la recherche décrite dans la thèse. Les travaux de thèse du M Thompson, Ph. D., comprenaient le développement de nouvelles méthodes de calcul pour analyser les observations d'imagerie différentielle angulaire et l'utilisation de ces méthodes pour découvrir une nouvelle exoplanète candidate autour de HR 8799 ; le développement du premier code multitechnique de recherche d'exoplanètes capable d'intégrer la vitesse radiale, l'astrométrie et les données d'imagerie à contraste élevé ; la réalisation de simulations et de tests en laboratoire de deux nouvelles techniques d'imagerie d'exoplanètes, et plus encore. L'examinateur externe de la thèse note que « c'est la combinaison d'une pensée innovante, d'une simulation rigoureuse et de résultats de banc d'essai en laboratoire qui rend le travail si impressionnant ». Le logiciel mis au point dans le cadre de la thèse du M Thompson, PhD, est accessible à tous et est déjà utilisé par d'autres chercheurs sur les exoplanètes, et son travail de développement d'instrumentation constitue un premier pas vers d'éventuelles contributions matérielles à l'Observatoire des mondes habitables. La CASCA est ravie de souligner les réalisations de M Thompson, Ph. D., en lui décernant ce prix.
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Space Telescope Science Institute @stsci.edu · 17/03/2025
The James Webb Space Telescope imaged young, giant exoplanets and detected carbon dioxide! The findings suggest that the giant exoplanets in the HR 8799 system likely formed like Jupiter and Saturn. (1/5) 🔭 🧪 🧵
This image shows the planetary system HR 8799. The background is black. At the center there is a symbol representing a star labeled HR 8799. The star’s light is blocked. There are four exoplanets, which look like fuzzy dots, pictured surrounding the star. Furthest from the star is a fuzzy, faint blue dot, labeled b, at the 10 o’clock position. At the 1 o’clock position, second furthest from the star is a blueish-white fuzzy dot labeled c. Just below that is an orange dot labeled e. At the 4 o’clock position, still near the star, is another fuzzy white dot labeled d.
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William Thompson @wrtastro.bsky.social · 16/03/2025
This is fantastic news. Upping grad and postdoc awards (both stipend and amount), and finally allowing non-Canadian/PRs to apply.
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William Thompson @wrtastro.bsky.social · 03/03/2025
Time for the promised thread on ε Eridani b! I should emphasize this manuscript is a submitted draft—comments from the community are very welcome. Bottom line: ε Eri b is likely a 1.0 Jupiter-mass planet, only 3.2pc away, on a 3.55 AU near-circular orbit, ~aligned with its debris disk. 🔭🪐🧪 [1/7]
Figure showing a the plausible orbits for Eps Eri b, and a panel showing the scale of the orbits relative to the outer debris disk model of Booth et al.A three panel figure showing the statistical distribution of inclination versus mass for the planet, broken down by seven different combinations of data. The scatter points follow an m*sin(i) curve, except for a series that does not include any RV data. A small black concentrated region shows the full model, with 1 and 3 sigma contours. The planet's mass is quoted at 0.98 +- 0.09 Mjup, and inclination as 41 +- 7 degrees.
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Matthew Kenworthy @mattkenworthy.bsky.social · 03/03/2025
A seriously impressive paper by Thompson+ on the “Revised Mass and Orbit of ε Eridani b: A 1 Jupiter-Mass Planet on a Near-Circular Orbit”. They’ve combined RV, direct imaging and absolute astrometry to revise the planet to ~1 M_Jup and e~0 - close to being a Solar System analogue. 🔭🪐 #astrodon
Twelve panels showing the past and future predicted positions of E Eridani b as coloured lasso hoops all lying roughly on top of one another, showing that the different detection methods agree with each other.A plot showing the probable mass of the planet versus the inclination of its orbit. There's a nice tight grouping superimposed on a weak horseshoe shaped cloud of possible points.
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William Thompson @wrtastro.bsky.social · 27/02/2025
We've been cooking up some fun new results for the planet Epsilon Eridani b! Submitted and should be on the arxiv by Monday. In the meantime, here's a couple teaser figures :) 🪐🔭🧪
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William Thompson @wrtastro.bsky.social · 27/02/2025
Stabilized variational non-reversible parallel tempered sampling—this MCMC can handle just about anything you throw at it! pigeons.run 🧪
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William Thompson @wrtastro.bsky.social · 11/02/2025
Hah, I spoke to soon! Now accepted to AJ 🪐
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William Thompson @wrtastro.bsky.social · 11/02/2025
Perhaps a little premature since it's still under review, but I'd like to share a couple results from our preprint now up on the arXiv: arxiv.org/abs/2502.05359 🔭 We dive deep into the orbits of the binary brown dwarf companion 🪐 GL229 Ba / Bb newly discovered this fall by Xuan et al. [1/4]
A two-panel figure, showing plausible orbits of the outer companion, then a zoom in (labelled "1000x zoom") to show the inner orbit of the two brown dwarfs.
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Matthew Kenworthy @mattkenworthy.bsky.social · 10/01/2025
Hon, Rappaport et al. on “A Disintegrating Rocky Planet with Prominent Comet-like Tails Around a Bright Star” with an orbital period of 1.27 days, this is a fascinating fourth example of this type of object. The eclipses vary from one orbit to another. 🔭🪐 #astrodon
Several panels showing the brightness of the star as a function of time. The star is blocked by a dust tail which creates a light curve with an initially steep drop, followed by a slow rise back to the normal flux of the star. Each eclipse has a slightly different depth and shape.
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Cees Bassa @cbassa.bsky.social · 04/01/2025
Combining the 8.4 million individual exposures (2TB of data) into a single keogram covering the 4 years from 2021 upto 2025 shows the repeated change in length of the night, and also highlights the small differences in sunset and sunrise times due to the eccentric orbit of the Earth around the Sun.
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William Thompson @wrtastro.bsky.social · 19/12/2024
Very minor update to PairPlots that addressing some vexing typographical details in the margin credible limits. They now exactly match the font of the rest of the plot. Before VS after, plus multiple series now have limits printed. Yes, I’m probably a little obsessive…
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William Thompson @wrtastro.bsky.social · 13/12/2024
So I know the central limit theorem is a thing, but can anyone explain why my daily # of GitHub commits follow a normal distribution centred on Wednesday?? #GitHubWrapped
A graph of GitHub commits by day of the week, with a peak on Wednesday and tails reaching Saturday/Sunday.
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William Thompson @wrtastro.bsky.social · 12/12/2024
🧪🔭 Attending AAS in DC this January? Join us at our introduction to Julia programming for astronomy workshop! #julialang
Poster with the following text:

Julia programming for Astronomy
Two day workshop @ AAS 245 Winter Meeting

January 11th and 12th

- introduction to Julia
- data frames
- plotting
- modelling
- high performance 
- multithreading
-create your first package!

Register through AAS portal!

Questions. Contact pebarrett@gwu.edu
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William Thompson @wrtastro.bsky.social · 03/12/2024
New version PairPlots.jl out now! We now calculate the effective sample size of your chains to determine the histogram binning and contour smoothing much more robustly. Before vs After:
A corner plot showing an MCMC chain - the contours look very blocky.Same as before, but with larger histogram bins and smooth contours.
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Julien Girard @juliengirard.space · 22/11/2024
Trying to understand and use 🦋 more, I created this "starter pack" to gather colleagues working in high contrast imaging (all flavors). Feel free to share stuff and invite more people. go.bsky.app/AasjG9B
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Andrew Steele @statto.bsky.social · 21/11/2024
There’s more to rainbows than the human eye can see: here’s how a rainbow extends into the infrared and ultraviolet. Photos: 1. Infrared 2. Visible (obviously) 3. Ultraviolet, and 4. A composite showing how UV is beyond the violet in a rainbow, and IR beyond the red end. 🧪 #photography
An infrared photo of a rainbow: a strange, ghostly-looking rainbow in a mostly black and white photo, with a faintly red outer edge and a cyan inner edge, and what look like a few even fainter ‘echo’ bows insideA regular visible-light pic of a rainbowAn ultraviolet picture of a rainbow: a dark, foreboding landscape with a deep purple stripe emanating from it, and a grey stripe insideA composite of the three preceding photos, showing that the infrared bow is ‘outside’ the visible light rainbow, and the ultraviolet bow ‘inside’
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William Thompson @wrtastro.bsky.social · 19/11/2024
AAS scheduled my dissertation talk (20 mins) and contributed talk (10 mins) in the same 1.5 hour session. Probably no one wants to hear me speak that much back to back, right?! Should I cancel?
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Allen Downey @allendowney.bsky.social · 19/11/2024
Recently I heard the word chartist for the first time in 57 years. Then within the same day, I heard it again. What are the chances? I used Bayes's theorem and a large corpus of English words to find out. www.allendowney.com/blog/2024/11...
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Leigh Fletcher @leighfletcher.bsky.social · 19/11/2024
Jupiter’s Poles: In a new review, Hue+2024 re-project the #JWST NIRCAM 2.12-micron observations of #Jupiter’s north (top) and south (bottom) polar regions (Hueso+2023), showing delicate hazes over each pole, with filaments and waves suggesting a richly dynamic polar hood. arxiv.org/abs/2410.20413
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Christian Fröschlin @chrfrde.bsky.social · 17/11/2024
Time lapse of #Saturn system from 2018 (including seven moons) revealing retrograde motion against starry backdrop of Milky Way. Covers three hours of real time. 54 x 400 x 0.5 sec unfiltered mono in Celestron 8" + ADC at f/10. #astrophotography
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Robin Edgar @robinedgar59.bsky.social · 17/11/2024
The 2024 Beaver Moon #SuperMoon rises behind the #Montréal landmark known as the Biosphère aka the former US pavillion of #Expo67 on Saturday November 16, 2024. www.facebook.com/robin.edgar/... #BeaverMoon2024 #SuperMoon2024 #MontréalMoments #MTLmoments #UrbanAstroPhotography #AstroPhotography
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Leigh Fletcher @leighfletcher.bsky.social · 16/11/2024
#Uranus reaches 2024 opposition tomorrow. For more than 30 years, #Hubble has watched the shifting Uranian seasons, from southern summer solstice (seen by Voyager 2 in 1986), through equinox in 2007, and (hopefully) on to northern summer solstice in 2030. #planetaryscience 📸 NASA/ESA/STScI/Fletcher
Hubble WFPC2 and WFC3 obserations of Uranus from 1995 to 2020, showing the changing view of the planet as it went from southern summer to northern spring.
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William Thompson @wrtastro.bsky.social · 13/11/2024
I got to meet real live astronaut Dr. Jenni Gibbons yesterday and give her a demonstration of our exo-🪐 imaging instrument SPIDERS! 🔭 #instrumentation
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Dr. William O. Balmer @balmer.bsky.social · 12/11/2024
expect the expected! new paper from our team on the arxiv today: our observations of the directly imaged planet AF Lep b with optical interferometry. we revise the planet's orbit and composition; both indicate unbothered formation within a disk via core accretion. arxiv.org/abs/2411.05917
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William Thompson @wrtastro.bsky.social · 10/11/2024
Oh and by the way, here’s new a tutorial on how to compare 1 vs. 2 planet models by calculating the full Bayesian evidence, in just five minutes flat: sefffal.github.io/Octofitter.j...
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William Thompson @wrtastro.bsky.social · 08/11/2024
New release of Octofitter, the ultra fast 🪐 orbit modelling code for Python and Julia. Version 5 with some nice speed improvements for RV modelling large datasets. Check it out here: - sefffal.github.io/Octofitter.j... - github.com/sefffal/octo... 🔭
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William Thompson @wrtastro.bsky.social · 08/03/2024
Now usable directly from Python, just “pip install octofitterpy” Demo here: github.com/sefffal/octo... 🪐
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