Dr. Allan Sacha Brun

I am an astrophysicist, director of research at @CEA_officiel, expert of the Sun, stars and their impacts on (exo)planets @CEAIRFU @INSU_CNRS

[ESA Operations @esaoperations]

Flyby success! @ESASolarOrbiter swept past Venus last night, using the planet's gravity to adjust its orbit and grant it a new view of the Sun's polar regions. Everything went as planned 🕹️🛰️✅

[ARCHIVED - NASA Sun & Space @NASASun]

Parker Solar Probe has made history.

After seven days of silence, Parker has resumed communication with Earth, confirming it's healthy after soaring just 3.8 million miles from the solar surface — the closest a human-made object has ever been to a star.

https://t.co/YgLBDsRlGy

[Dr. Allan Sacha Brun @ASachaBrun]

Very nice collaborative work masterly led by Valeriy on the occurrence of superflares in solar-type stars, in this busy solar activity year it is quite timely.
Superflares once per Century https://t.co/8WvuINeBD9

[Dr. Allan Sacha Brun @ASachaBrun]

You can find the ApJ paper there:
https://t.co/Gl42NUmL6e via @AAS_Publishing

[Dr. Allan Sacha Brun @ASachaBrun]

https://t.co/4WM9fZtwOH
Very nice work with Louis and Ana on red giant star magnetism. and how one can explain their low amplitude.

[Dr. Allan Sacha Brun @ASachaBrun]

Great Whole Sun workshop at IAC, Big thank you to Valentin, Fernando, Daniel, Ernest and the solar team. Looking forward to Whole Sun @ IPa next March 3-21 2025.

[Dr. Allan Sacha Brun @ASachaBrun]

@slyardley yes I agree, @SolarOrbiter saw a bigger flare on the far side last May 2024. Let’s agree the recent X9 is the biggest on the dayside as of today. It is quite interesting to see how active the Sun’s southern hemisphere has become over the last weeks, pushing up the sunspot number.

[ESA Technology @ESA_Tech]

📽️Europe's eclipse-making double-satellite mission Proba-3 has a 29 November launch date! Watch to learn about the mission set to open up new views of our Sun's surrounding atmosphere https://t.co/eCyAgpX9JZ

[ESA Space Transport @ESA_transport]

#Ariane6 first flight: Phase 2 complete! 2️⃣✅🎉

With the reignition of the upper stage & deployment of all CubeSats, Ariane 6 has completed it mission. This 2nd phase of the first flight consists of events 6 to 9 in this infographic: Ariane 6 has proven its brand new upper stage reignites in orbit and can deploy multiple varied missions into orbit.

[Dr. Allan Sacha Brun @ASachaBrun]

So happy with the selection of JEDI and to be part of the adventure. Congratulations to Don and the whole JEDI team for a fantastic job. Even more fun and top space weather science to come with JEDI instrument and Vigil mission, looking forward to it.

[NASA @NASA]

Studying the Light Side with JEDI 🌞

We've selected the Joint EUV coronal Diagnostic Investigation (JEDI) to travel through space on @esa's upcoming Vigil mission. JEDI will capture images of the Sun in extreme ultraviolet light: https://t.co/7MQAabZ4dH

[Dr. Allan Sacha Brun @ASachaBrun]

So many X flares, the Sun is making quite a show! Beautiful show also on Earth, with bright Aurorae all the way to southern France. Here, a movie of the last 48 hours of the Sun, quite impressive.

[@mathewjowens.bsky.social @mathewjowens]

It is a *mess* out there.

[Dr. Allan Sacha Brun @ASachaBrun]

What an active Sun over the last 24-48h. We just got a X4.5 flare after many M7-9 and several X…

[Dr. Allan Sacha Brun @ASachaBrun]

Great total solar eclipse in Texas, beautiful prominence on the bottom right and complex corona as we near maximum of solar cycle 25. thx to colleagues (Eric and Aditi) for sharing their beautiful pictures with me ☀️

[ESA Operations @esaoperations]

AR 3590 will become increasingly magnetically connected with Earth. Any 'Energetic Solar Particles' following the magnetic field lines stretching out from the Sun are likely to impact Earth and satellites in orbit.

Info and updates at:
https://t.co/apSGs1JzFL

[ESA Operations @esaoperations]

A highly active region of the Sun recently fired off three of the strongest type of solar flare (X-class).

The largest, an ‘X6.3’ flare released at 23:43 CET last night was the strongest solar flare observed during the current solar cycle.

#SolarFlare #SpaceWeather

[@travis-metcalfe.bsky.social @travis_metcalfe]

Interesting new analysis of Sun-like dynamo simulations, showing a minimum of the magnetic field slightly above the solar Rossby number! Note that Weakened Magnetic Braking appears to halt the rotational evolution *before* stars reach the bottom of the "V" https://t.co/ayfwoYz5jX

[@adamfinley.bsky.social @AdamF_Astro]

A good occasion to look where we are in the Sun's magnetic activity cycle? Here I compare the current sunspot cycle (25) to the last two: cycle 23 from 1996-2008, and 24 from 2008-2019. This cycle may have a similar shape, peaking in 2023 and again in 2025? Only time will tell!

[Dr. Allan Sacha Brun @ASachaBrun]

Solar-type magnetism vs time, a new story is emerging, with possibly a minimum of activity near solar (on convection and rotation) conditions. Read more on this interesting outcome published by @Qnorastraz - https://t.co/aojGG6Mk6G

[Horizon Magazine @HorizonMagEU]

Researchers attempt to shed light on the Sun to trace its origins and ours.

Read more ➡️ https://t.co/qo5FZIDeW9

#HorizonEU