Julien Girard

SETI Live record button logo. Text: Closest Exoplanet Yet? with Franck Marhis and Julien Girard. Background: Artist's concept of a gas giant planet orbiting at a distance from a bright star. Inset: Photos of Franck Marchis and 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

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!

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

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...

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.

"This is just a small peek"
In 9 hours, livestream!

Habitable Worlds Observatory News - NASA Science Building on the foundation of the Habitable Worlds Observatory (HWO) Technology Maturation Project Office (TMPO), NASA is now establishing the HWO Community

Habemus CSIT for the Habitable Worlds Observatory (HWO)

science.nasa.gov/astrophysics...

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...

The two gas giant planets YSES 1b has a circumplanetary disk surrounding a purple coloured visualisation of the gas giant, and a sandy coloured gas giant 1c in the lower right. The star can be seen in the distance. The image is by Ell Bogat at UMD.

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

Congrats Yoni!!!

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!!

Punchline Queen

Je suis curieux des propositions et mécanismes pour accueillir (attirer?) des chercheurs/scientifiques en France et en Europe. Comment le faire sans revaloriser les chercheurs en France? A 50% du salaire US, je prends! À 25%, non.

Actually with captions

I could not help it…

(note, the top picture was taken in Jura, France by the weather forecast group a météo franc-comtoise)

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

Line drawing of JWST on a composite background of the Cosmic Cliffs observed by JWST

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

Well deserved on bsky as well, congrats!!

Quel est votre plan? @raphaelglucksmann.bsky.social @aurorelalucq.bsky.social Rien que les chercheurs français aux états-unis ça représente pas mal de monde et si on travaille aux Etats-Unis c'est que 1) les projets nous y ont amenés 2) les conditions de recrutement/salaire en France sont étroites.

This is a young, scaled up version of our solar system, one of the bonafide exoplanetary systems in our field of high contrast imaging and spectroscopy.

The outreach team at STScI has done a wonderful job too!

4/4

@kellenlawson.bsky.social has managed to deconvolve coronagraphic images with a spatially varying (and complex) point spread function (PSF, the optical "response" of the telescope+instrument), an ill-posed problem but that's how we can see all 4 exoplanets simultaneously in this imaged.

3/n

, using the long wavelength bar (or wedge) occulter at its narrowest end to be able to recover planet e (the closest one) and also be able to get those new colors, only available from space.

2/n

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...

This image is actually deconvolved and reconvolved (for each filter) by some kernel of the size of the core of the PSF. We do not resolve the planets, we would need a telescope of many km diameter ;)

Otherwise planet e is blended into the side lobes of the "flowery" PSF of the NIRCam Coronagraph.

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...

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

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).

It was actually, one of the better greek (or Greek American) pita + lamb I had since living here. Certified by another French guy for what it is worth. 🙃

It was a great sunny day.

I have so much admiration and respect for all these engineering personnel in bunny suits. They make things work, they test systems so they are flight ready and near perfection. 2/2

Drive to Goddard today, had a meeting about the Roman Coronagraph with an esteemed colleague, discussed awesome Webb observation with another amazing collaborator, ate at a Greek food truck and finally went to see the Nancy Grace Roman space telescope in the high-bay clean room. 1/2

Observations and Light Curve of Sagittarius A*

It was so moving to me!

This is a really cool new results with evidence of more detailed photometric variations. Webb detected both faint flickers and brighter flares in this black hole activity light curve (see video)! Well done!!! 2/

webbtelescope.org/contents/med...