Julien Girard
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juliengirard.space
Julien Girard
@juliengirard.space
astronomer, scientist and coronagraphist at STScI, exoplanet portraitist, extreme turophile, father, grumpy urban farmer hobbyist
he/him
views EN FR ES my own
https://linktr.ee/juliengirard
🦋 🐘 @djulik on 🦤
Pinned
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
Good news! En hora buena!

I know this is probably not the time yet but choosing Tenerife (or even Madrid or Barcelona) for Spanish HQ would be wise, more attractive for scientists, engineers, staff and their families :)

No offense for Santa Cruz de La Palma, looks beautiful!!
TMT International Observatory LLC will jointly develop with the Ministry of Science, Innovation and Universities a detailed roadmap toward the potential realization of the TMT at the Observatorio del Roque de los Muchachos (La Palma, Spain).
TMT Explores a Promising Path Forward in Spain
TMT is exploring a promising avenue for a new observatory based in Spain.
www.tmt.org
November 12, 2025 at 3:54 PM
Reposted by Julien Girard
this is from a paper I'm putting together of a 300 K brown dwarf and it's kind of insane how similar it is
November 11, 2025 at 12:59 AM
Jupiter aurora movie by JWST NIRCam!
www.youtube.com/watch?v=b1Fo...
November 5, 2025 at 7:48 PM
Reposted by Julien Girard
🤩The @4most-eu.bsky.social (#4MOST) facility on @eso.org VISTA telescope in Chile achieved first light.
#MPE scientists played a leading role in developing the Operations System, enabling to link #eROSITA’s X-ray universe with large-scale structure of galaxies.
➡️ More: www.mpe.mpg.de/8102833/news...
4MOST Begins its Journey of Cosmic Discovery
4MOST embarks on a cosmic journey, capturing spectra of thousands of celestial objects simultaneously, unlocking secrets of the universe.
www.mpe.mpg.de
October 21, 2025 at 12:01 PM
Reposted by Julien Girard
First Light for 4MOST!

The 4-metre Multi-Object Spectroscopic Telescope (4MOST) has captured its very first spectra!

Video Credit: AIP/R. de Jong, AIP/K. Riebe, AIP/A. Saviauk, CRAL/J.-K. Krogager
First Light for 4MOST!
YouTube video by 4-meter Multi-Object Spectroscopic Telescope
youtu.be
October 21, 2025 at 12:00 PM
Love the 2b_or_not_2b repo!!
Some sad #exoplanets news in a paper led by me: “YSES 2b is a background star”. A distant M dwarf star some 2 kiloparsecs behind the star just so happens to have a non-zero proper motion in EXACTLY the wrong direction: this required multiple GRAVITY observations to solve… #astrosci #astrodon
September 14, 2025 at 4:10 AM
Reposted by Julien Girard
Two papers announcing the discovery of a directly imaged 6 Jupiter mass planet around binary system HD 143811 AB Squicciarini+ and Jones+ in Sco-Cen - Keck, Gemini and VLT all imaging this companion and confirmed with several years of common proper motion. #astrodon #exoplanet #exosci
September 9, 2025 at 9:29 AM
Reposted by Julien Girard
JWST successfully observed interstellar object (ISO) 3I/ATLAS. Interesting results. The composition of the coma could be due to a few different scenarios. Additional JWST observations of the object closer to the sun are needed. science.nasa.gov/blogs/3iatla...
NASA’s Webb Space Telescope Observes Interstellar Comet - NASA Science
NASA’s James Webb Space Telescope observed interstellar comet 3I/ATLAS Aug. 6, with its Near-Infrared Spectrograph instrument. The research team has been
science.nasa.gov
August 25, 2025 at 10:28 PM
Amazing!!!! A NEW gap-carving planet! So far, we haven't been able to image many. WISPIT 2b, like PDS 70 b&c is imaged at many wavelengths from 656nm (H⍺, blue here) to 3.7µm (👏MagAO-X @xwcl.science.web.brid.gy). VLT/SPHERE polarized scattered light at 1.6µm+reddish planet at 2.2µm in the gap, wow!
Proud supervisor moment: #LeidenObservatory graduate student Richelle van Capelleveen led one of two papers on our discovery of WISPIT 2b, a 5 Jupiter mass exoplanet clearing a path in a circumstellar disk. Laird Close and his team saw it in H-alpha, indicating gas accretion #astrodon 🔭 🧪
August 26, 2025 at 12:11 PM
Reposted by Julien Girard
Next #SETILive: Closest Exoplanet Yet?
TODAY, 8 August, 3:15 pm PDT

Join astronomers @allplanets.bsky.social and Julien Girard (STScI) as they discuss recent evidence of a Saturn-mass gas giant orbiting Alpha Centauri A—located just 4 light-years away. 🧪 🔭

WATCH LIVE: buff.ly/TplMAD5
August 8, 2025 at 10:00 PM
Wow, Tonight I just completed 8 years @stsci.edu. I love it 😊

I realize I now have worked there in Baltimore as much as I spent @eso.org in Chile. 16 years as scientist, collectively supporting instruments, operations, maximizing the science return at major observatories, ground and space!
August 6, 2025 at 11:29 PM
Reposted by Julien Girard
The Space Telescope Science Institute's MAST archive contains 300 million astronomical observations from over 23 different missions.

Here is an animation showing how the archive has built up over time.

Credit: Julie Imig, STScI
August 1, 2025 at 1:16 AM
Experiencing FOMO big time, not attending #HWO2025) I am glad a lot is youtube broadcasted. I am especially eager to watch these panels sessions on ground/based synergies and on how the #RomanCoronagraph will inform the design choices of the HWO coronagraphs www.youtube.com/watch?v=7Vq3...
STScI Director Dr. Jennifer Lotz (left) moderates a panel on observatory synergies at the Habitable Worlds Observatory conference today in Washington, D.C. #HWO2025 #HWO25 🔭 🧪 ☄️
July 29, 2025 at 9:39 PM
Who saw this coming?

Maybe that should go into the discussion of what @eso.org will do after it's ELT, an ELT-N with a TMT design?

I think as a community what we all want is A >25m telescope in the North.
July 23, 2025 at 6:49 PM
"This is just a small peek"
In 9 hours, livestream!
Introducing...your sneak peek at the cosmos captured by NSF–DOE Vera C. Rubin Observatory!

Can you guess these regions of sky?

This is just a small peek...join us at 11am US EDT for your full First Look at how Rubin will #CaptureTheCosmos! 🔭🧪

#RubinFirstLook
ls.st/rubin-first-look-livestream
June 23, 2025 at 5:20 AM
Please watch the @aas.org Press Conference where @balmer.bsky.social presented this thrilling result: THE NEW(even if expected from astrometry)LY IMAGED, COLD (~2ºC), MATURE giant exoplanet 14 Her c with JWST/NIRCam!!!

Congrats Daniella, William and the whole team 😀

www.youtube.com/live/Z7niXAH...
June 10, 2025 at 7:18 PM
Reposted by Julien Girard
Dr. Kielan Hoch has a #Nature paper on #JWST observations of the star YSES 1 with its two gas giant planets. She and her team have discovered a circumplanetary disk around the larger 1b and silicate clouds in 1c. Wonderful results and more to come - watch this space! #exoplanet #astrodon
June 10, 2025 at 5:56 PM
Chen Xie, Christine Chen et al., colleagues of our EPSIG group at STScI/JHU just published water ice detections with #HighContrast Near-Infrared (IFU) Spectroscopy with #JWST/NIRSpec!!
NEW: Is frozen water around other stars? #NASAWebb provided proof for the first time: It is! Webb identified water ice around HD 181327, a Sun-like star that lies 155 light-years away. The majority is found where it’s coldest—farthest from the star: webbtelescope.pub/42Vopw0 🔭 🧪
May 14, 2025 at 3:55 PM
I could not help it…

(note, the top picture was taken in Jura, France by the weather forecast group a météo franc-comtoise)
March 26, 2025 at 4:44 PM
We'll be presenting this Coronagraphy JWebbinar with Aarynn Carter and Jonathan Aguilar, register here before March 30 if you're interested.

#JWST #Coronagraph
www.stsci.edu/jwst/science...
under 2025, it's number 40
Registration is now open for the next JWebbinar – NIRCam and MIRI Coronagraphy: An Update 3 Years into #JWST Operations – to be held on April 3rd. Get the details: ow.ly/ewNq50VgoQW
March 25, 2025 at 10:50 PM
Reposted by Julien Girard
A new series of python-based Jupyter notebooks are now available for all four #JWST instruments and 13 observing modes. Read more: ow.ly/bjZ850VnlG8
March 24, 2025 at 1:27 PM
So happy & proud of what William Balmer (PhD student @johnshopkinsiaa.bsky.social + in our group at @spacetelescope.bsky.social) has managed to do with the JWST/NIRCam Coronagraphy mode. To achieve this incredible image, we had to push performance to the max,

1/n

science.nasa.gov/missions/web...
March 17, 2025 at 10:35 PM
Direct Imaging aleeeert!

JWST keeps delivering, this is a record breaking 0.3 MJup (~1 Saturn mass) for direct imaging, taken at 11 µm with one of MIRI's coronagraph, right in the disk where it was ~expected.

Anne-Marie Lagrange and colleagues strike again 👏 🙌
arxiv.org/abs/2502.15081
Evidence for a sub-jovian planet in the young TWA7 disk
Planets are thought to form from dust and gas in protoplanetary disks, and debris disks are the remnants of planet formation. Aged a few Myr up to a few Gyr, debris disks have lost their primordial ga...
arxiv.org
February 27, 2025 at 12:37 AM
I met @stevenwilsonhq.bsky.social during his first visit of Paranal in May 2017. I was just getting up after many observing nights, going to the gym probably.. Christine was the head of logistics. It's cool when talented artists visit, I miss that (and the southern skies, the colleagues @eso.org).
February 26, 2025 at 4:53 PM