William Thompson
@wrtastro.bsky.social
Herzberg Instrument Science Fellow at the National Research Council in Victoria, Canada. Imaging exoplanets and writing #JuliaLang tools.
(most of) The local team together to see SPIDERS off!
Fingers crossed the ride over wont be too bumpy 🫨
Fingers crossed the ride over wont be too bumpy 🫨
October 23, 2025 at 8:45 PM
(most of) The local team together to see SPIDERS off!
Fingers crossed the ride over wont be too bumpy 🫨
Fingers crossed the ride over wont be too bumpy 🫨
SPIDERS is out of the clean room and almost ready to ship — it’s really happening! #instrumentation #exoplanets
October 18, 2025 at 10:10 PM
SPIDERS is out of the clean room and almost ready to ship — it’s really happening! #instrumentation #exoplanets
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)
(Octofitter is a package for Bayesian modelling of exoplanet orbits)
July 14, 2025 at 11:04 PM
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)
(Octofitter is a package for Bayesian modelling of exoplanet orbits)
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
🔭 #exoplanets
July 10, 2025 at 6:25 PM
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
🔭 #exoplanets
There’s something very special about the gulf islands 🏝️
July 6, 2025 at 8:24 PM
There’s something very special about the gulf islands 🏝️
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 🔭
June 3, 2025 at 3:12 PM
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 🔭
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 🔭
* 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 🔭
May 22, 2025 at 3:32 PM
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 🔭
* 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 🔭
Here's a bonus video of SPIDERS maintaining a dark hole in real time, despite simulated turbulence!
April 29, 2025 at 5:34 PM
Here's a bonus video of SPIDERS maintaining a dark hole in real time, despite simulated turbulence!
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
We use a special coronagraph to interfere the starlight with itself, like a classic double slit experiment... [1/3]
🔭 #Instrumentation #exoplanets
April 29, 2025 at 5:19 PM
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
We use a special coronagraph to interfere the starlight with itself, like a classic double slit experiment... [1/3]
🔭 #Instrumentation #exoplanets
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! 🔭
March 25, 2025 at 5:03 PM
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! 🔭
Here are some individual draws from the posterior. I think any individual row should work. The angular parameters are in units of radians, period in years, tp in MJD (ps: plain text copyable version in the alt-text).
We'll post the full posteriors and reproducible scripts once accepted.
We'll post the full posteriors and reproducible scripts once accepted.
March 4, 2025 at 4:40 PM
Here are some individual draws from the posterior. I think any individual row should work. The angular parameters are in units of radians, period in years, tp in MJD (ps: plain text copyable version in the alt-text).
We'll post the full posteriors and reproducible scripts once accepted.
We'll post the full posteriors and reproducible scripts once accepted.
We are now able to predict the planet's location to a narrow region on any given date. This figure shows how these predictions depend on the different data sources included. [5/7]
March 3, 2025 at 6:51 PM
We are now able to predict the planet's location to a narrow region on any given date. This figure shows how these predictions depend on the different data sources included. [5/7]
There's been lots of interest in this planet in the intervening years, of course. Now with JWST, we hope that an imaging detection is near! In anticipation, we've updated the orbit based on a full 40 years of RV data, and astrometry from Hipparcos, Hubble, Gaia DR2, and DR3. [3/7]
March 3, 2025 at 6:51 PM
There's been lots of interest in this planet in the intervening years, of course. Now with JWST, we hope that an imaging detection is near! In anticipation, we've updated the orbit based on a full 40 years of RV data, and astrometry from Hipparcos, Hubble, Gaia DR2, and DR3. [3/7]
The first hints of ε Eri b, also known as "AEgir," were reported in 1995 by Campbell, Walker and Yang based on RV data from CFHT in the 80s, then confirmed with RV by Hatzes+ in 2000, and with the addition of Hubble absolute astrometry in 2006 by Benedict+ (see fig.) [2/7]
March 3, 2025 at 6:51 PM
The first hints of ε Eri b, also known as "AEgir," were reported in 1995 by Campbell, Walker and Yang based on RV data from CFHT in the 80s, then confirmed with RV by Hatzes+ in 2000, and with the addition of Hubble absolute astrometry in 2006 by Benedict+ (see fig.) [2/7]
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]
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]
March 3, 2025 at 6:51 PM
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]
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]
Yes indeed! We find a mutual inclination of 10 ± 7 °.
My money is on them being close to co-planar, and this small signal comes from systematics in the astrometry or disk models. But only time will tell for sure.
My money is on them being close to co-planar, and this small signal comes from systematics in the astrometry or disk models. But only time will tell for sure.
February 27, 2025 at 11:06 PM
Yes indeed! We find a mutual inclination of 10 ± 7 °.
My money is on them being close to co-planar, and this small signal comes from systematics in the astrometry or disk models. But only time will tell for sure.
My money is on them being close to co-planar, and this small signal comes from systematics in the astrometry or disk models. But only time will tell for sure.
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 :)
🪐🔭🧪
🪐🔭🧪
February 27, 2025 at 10:16 PM
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 :)
🪐🔭🧪
🪐🔭🧪
Stabilized variational non-reversible parallel tempered sampling—this MCMC can handle just about anything you throw at it!
pigeons.run
🧪
pigeons.run
🧪
February 27, 2025 at 2:43 PM
Stabilized variational non-reversible parallel tempered sampling—this MCMC can handle just about anything you throw at it!
pigeons.run
🧪
pigeons.run
🧪
Lastly we pin down the mutual inclination of the orbit of the Ba/Bb pair versus their orbit around the primary, A, at 31.0±2.5°
February 11, 2025 at 2:33 PM
Lastly we pin down the mutual inclination of the orbit of the Ba/Bb pair versus their orbit around the primary, A, at 31.0±2.5°
Ultimately, we find that we can determine the dynamical mass of the binary pair independently from the inner orbit—and it agrees to better than 1% with the mass we find from the outer orbit... a great test of our ability to measure the masses of directly imaged planets! [3/4]
February 11, 2025 at 2:33 PM
Ultimately, we find that we can determine the dynamical mass of the binary pair independently from the inner orbit—and it agrees to better than 1% with the mass we find from the outer orbit... a great test of our ability to measure the masses of directly imaged planets! [3/4]
First, we show that we can find a low SNR companion in the GRAVITY data despite the rapid orbital motion, and that orbit agrees near-perfectly with RV data. Very promising for planning future observations of faint, rapidly orbiting planets! [2/4]
February 11, 2025 at 2:33 PM
First, we show that we can find a low SNR companion in the GRAVITY data despite the rapid orbital motion, and that orbit agrees near-perfectly with RV data. Very promising for planning future observations of faint, rapidly orbiting planets! [2/4]
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]
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]
February 11, 2025 at 2:33 PM
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]
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]
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…
Yes, I’m probably a little obsessive…
December 19, 2024 at 7:14 PM
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…
Yes, I’m probably a little obsessive…
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
December 13, 2024 at 7:05 PM
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