Royal Observatory of Belgium

Second workshop on Belgian Time and Frequency Services (BTFS)

Le Binh San Pham — Wed, 15 Apr 2026 15:40:32 +0000

On Tuesday 10 March 2026, the second workshop on Belgian Time and Frequency Services (BTFS) was held at the Royal Observatory of Belgium (ROB). It brought together around thirty interested participants to discuss the latest developments and applications. Thanks to the use of an optical network for the distribution of time and frequency signals, this technology is immune to GNSS threats such as jamming and spoofing, which significantly improves signal reliability. The high participation in this workshop confirms a growing interest in BTFS.

Extension of the Belgian network

The workshop was opened by Koen Lefever of Belspo, sponsor of the BOOSTED project, which aims to develop an optical time and frequency transfer network. Raphaël Marion (ROB) then presented an overview of the Belgian time and frequency network. He explained the commissioning of the first section in December 2025 and outlined the ambitious expansion plans for 2026. New connections are planned, notably to the metrology service of the FPS Economy and to the universities of Mons and Louvain-la-Neuve. A connection to GÉANT’s pan-European Core Time & Frequency Network (C-TFN) is also on the roadmap.

Need for a robust network

Although BTFS were initially developed for scientific research, interest from other sectors is growing rapidly. In particular, the telecommunications, energy and transport sectors are showing an interest in an independent and extremely accurate time signal to enhance the security and reliability of their critical infrastructure. This development is fully in line with the vision of the European Commission’s Joint Research Centre (JRC). During his presentation, Lukasz Bonenberg emphasised the importance of developing robust, GNSS-independent terrestrial time synchronisation networks. According to the JRC, such networks are essential for building a resilient European positioning, navigation and time synchronisation (PNT) system.

The Netherlands and Switzerland

International experiences were also presented. The Dutch organisation SURF proudly announced the commissioning of its national time and frequency network for research and education. Since January 2026, a White Rabbit time signal, originating from the National Metrology Institute VSL in Delft, has been distributing the legal time UTC(VSL) to eleven sites via SURF’s fibre-optic network.

Furthermore, METAS, the Swiss National Metrology Institute, presented several practical applications of its network. In Switzerland, a 450-kilometre network is now operational for the distribution of White Rabbit time signals, primarily used by the financial sector, defence and telecommunications. An optical frequency signal is also broadcast for advanced scientific applications, such as precision spectroscopy and fibre sensing.

Technology and innovation

The second part of the workshop focused on technical aspects. Lisa Van Loo (Belnet) and Guillaume Le Portz (ORB) presented the architecture of the BTFS network as well as the excellent monitoring results from the first connections.

Net Insight then presented its Zyntai technology, an innovative solution that operates as an overlay on existing IP networks. By performing statistical weighting of multiple time sources, this technology—which is compatible with the BTFS network—enables the distribution of a precise time signal over long distances, with performance levels falling between PTP and WR.

Finally, Prof. Kasper Van Gasse of the Photonics Research Group (UGent and imec) presented ongoing research into integrated photonics. This work aims to develop lasers that are more compact, more robust and easier to manufacture, with applications in metrology and quantum technologies.

The workshop concluded with a relaxed get-together over drinks, giving participants the opportunity to share their experiences and explore new avenues for collaboration. This second edition clearly confirmed the growing importance of reliable time distribution, as well as the keen interest shown by both the scientific community and industry.

The post Second workshop on Belgian Time and Frequency Services (BTFS) appeared first on Royal Observatory of Belgium.

A New View of the Sun’s Corona

Le Binh San Pham — Mon, 13 Apr 2026 10:48:32 +0000

The Belgian-led ASPIICS coronagraph aboard ESA’s Proba-3 mission reveals a dynamic birthplace of the solar wind

Observations made by the ASPIICS coronagraph aboard the Proba-3 mission of ESA reveal a world of small-scale activity in the Sun’s inner corona, according to a new study led by the Royal Observatory of Belgium. These observations suggest that the region where the solar wind forms is filled with constantly moving structures that may help drive the solar wind itself.

The Sun’s extended atmosphere, the solar corona, is a realm of extremes. Temperatures exceed a million degrees — much hotter than the solar surface — and from this place streams a continuous supersonic flow of plasma (electrically charged gas) known as the solar wind. The slower component of this wind, the slow solar wind, is particularly puzzling: it varies strongly in speed, density, and composition, and its exact origin in the inner corona has remained debated for decades.

This image was recorded on 16 July 2025. At this time, the Sun was at solar maximum, the most active time in the 11-year solar cycle. This meant streamers carrying solar wind could point in all directions. As the Sun’s activity slows down over the next few years and the Sun’s magnetic field becomes less chaotic, streamers will mostly come from near the solar equator. The (artificially coloured) yellow part of the image shows the Sun in ultraviolet light, recorded by the SWAP telescope on ESA’s Proba-2 spacecraft. The green image around it was captured in visible light by the ASPIICS coronagraph on ESA’s Proba-3. Credit: ESA/Proba-3/ASPIICS & ESA/Proba-2/SWAP, A. Zhukov (ROB).

Observing the inner part of the solar corona has long been difficult. Telescopes that view the Sun with its low corona in X-rays and extreme ultraviolet usually cannot see far enough outward, while traditional coronagraphs — instruments that block the bright solar disk to reveal the faint corona — typically observe the corona farther from the Sun. This results in an observational gap exactly where the slow solar wind is thought to form.

The Proba‑3 mission of the European Space Agency (ESA), launched in December 2024, uses a unique technique to close this gap: two spacecraft flying in millimetrically precise formation 144 metres apart. One satellite carries a disk that covers the bright solar surface, while the other hosts a telescope. Together they form a giant coronagraph that creates artificial total solar eclipses in space on demand, allowing scientists to observe the faint corona very close to the Sun for hours at a time. The mission’s main instrument, the ASPIICS coronagraph (Association of Spacecraft for Polarimetric and Imaging Investigation of the Corona of the Sun) effectively fills the observational gap between extreme-ultraviolet solar telescopes and traditional coronagraphs.

The (artificially coloured) yellow part of the video shows the Sun in ultraviolet light, recorded by the SWAP telescope on ESA’s Proba-2 spacecraft. The greyscale area around it is based on data captured in visible light by the ASPIICS coronagraph on Proba-3. This data is processed to enhance contrast. You can see flows of solar wind moving away from the Sun in all directions. In some regions, particularly around the bottom of the video, you can see some material also falling back towards the Sun. In the second half of the video, a coronal mass ejection expands towards the right. Credit: ESA/Proba-3/ASPIICS & ESA/Proba-2/SWAP (ROB), A. Debrabandere (ROB).

Watch the full video. The (artificially coloured) yellow part of the video shows the Sun in ultraviolet light, recorded by the SWAP telescope on ESA’s Proba-2 spacecraft. The greyscale area around it is based on data captured in visible light by the ASPIICS coronagraph on Proba-3. This data is processed to enhance contrast. You can see flows of solar wind moving away from the Sun in all directions. In some regions, particularly around the bottom of the video, you can see some material also falling back towards the Sun. In the second half of the video, a coronal mass ejection expands towards the right. Credit: ESA/Proba-3/ASPIICS & ESA/Proba-2/SWAP (ROB), A. Debrabandere (ROB).

In a new study led by the Royal Observatory of Belgium and published in the Astrophysical Journal Letters, researchers present the first scientific results from Proba-3/ASPIICS. ‘The observations reveal that the region where the slow solar wind originates is filled with ubiquitous small-scale dynamics: tiny, faint, rapidly evolving plasma structures flowing outward, but also sometimes inward, through the corona,’ says Andrei Zhukov, the Principal Investigator of ASPIICS and the lead author of the study. These motions indicate that the solar corona is far more dynamic at small scales than previously observed. Such dynamics may be linked to magnetic reconnection — the rearrangement of magnetic fields that may heat and accelerate plasma. Tracking these tiny structures provides new clues about how the slow solar wind forms and how the Sun releases mass and energy into the interplanetary space.

Proba-3 is an ESA mission involving scientific and industrial partners across Europe. Belgium plays a central role in the mission’s technology and science:

Redwire in Kruibeke provided spacecraft avionics, assembly, testing, and early operations.
The Centre Spatial de Liège led the design, assembly and testing of the ASPIICS telescope, and served as the industrial prime contractor, coordinating a large European consortium that built the instrument.
The Royal Observatory of Belgium leads the scientific investigation, including the instrument’s Principal Investigator team and the mission’s science operations.

The Proba-3 spacecraft are operated from ESA’s European Space Security and Education Centre in Redu. The strong Belgian involvement reflects decades of expertise in solar physics and development of space hardware.

The first results mark only the beginning of Proba-3’s exploration of the solar corona. ‘Since the start of its nominal mission in July 2025, Proba-3/ASPIICS acquired more than 250 hours of data, which is equivalent to the duration of thousands of natural total solar eclipses observed from the ground,’ says Andrei Zhukov. Scientists expect Proba-3 to uncover even more new details about fundamental processes in the corona, such as how the solar wind is produced, and how magnetic eruptions known as coronal mass ejections are launched from the Sun.

The Belgian contribution to Proba-3 is supported by the GSTP and PRODEX programmes of ESA, by the Belgian Federal Science Policy Office (BELSPO), and by the Solar-Terrestrial Centre of Excellence.

ESA web story: https://www.esa.int/Science_Exploration/Space_Science/First_Proba-3_science_surprisingly_speedy_solar_wind

The post A New View of the Sun’s Corona appeared first on Royal Observatory of Belgium.

Battle of the Scientists 2026

Flore Van Maldeghem — Mon, 02 Mar 2026 09:01:37 +0000

On February 6, six researchers, including two from the Royal Observatory of Belgium, shared their knowledge on solar storms and space weather with a special audience during the eleventh Battle of the Scientists. 2,700 enthusiastic primary school children, 500 of whom were in the auditorium and 2,200 via livestream, voted for the most insightful presentation. The Belgian Space Weather Centre (STCE) and The floor is yours joined forces to organise this edition.

The Battle of the Scientists is a competition in which scientists present their research so clearly that even children can understand it. Even more, the children have the final say. They present, keep track of time, form a children’s jury and vote for the clearest scientist. This year, this honor went to De Mozaïek primary school from Kessel-Lo.

After each presentation, the children’s jury gives critical feedback and the children from the audience can ask questions.

Speaker Cis Verbeeck from the Royal Observatory of Belgium.

The central theme was ‘space weather’. This concerns the eruptions and particle streams from the Sun, which affect the Earth and our technology. Think, for example, of solar storms (sudden bursts of energy on the Sun), solar wind (a stream of charged particles coming from the Sun), and gigantic clouds of charged particles that the Sun explosively ejects into space. In Belgium, we even have a space weather centre where scientists collect and analyse data and issue space weather reports. The STCE is located in Uccle and is known far beyond the country’s borders.

The consequences of space weather for us? Satellites failing, disrupted GPS systems and in extreme cases even damaged electricity networks on Earth.

Speaker Andreas Debrabandere from the Royal Observatory of Belgium.

Based on a short video, the pupils selected the speakers listed below (Dutch).

Cis Verbeeck(Royal Observatory of Belgium): “Hoe voorspel je een super-zonnestorm?” (presentation)
Esmee Tackx en Stefan De Raedemaeker(KU Leuven): “Marsrover Marcel en de wraak van de zon” (presentation)
Dries Van Baelen(Defence): “Hoe bel je een soldaat in het midden van de woestijn?” (presentation)
Myrthe Flossie(KU Leuven): “Help! Zonnedeeltjes vallen astronauten aan” (presentation)
Andreas Debrabandere(Royal Observatory of Belgium): “Een eclips bouwen om ruimteweer te zien” (presentation)

In the end, Myrthe Flossie (KU Leuven) was chosen as the winner with her presentation on how we can protect astronauts from dangerous plasma particles from a solar storm. Dries Van Baelen (Defence) came in second and talked about HF radio and how to ensure that soldiers can continue to communicate safely with each other, even during a solar storm.

You can also watch the entire show on YouTube!

The Battle of the Scientists 2026 is an organisation of The Floor is Yours in collaboration with the Solar-Terrestrial Centre of Excellence (STCE), with the support of Redwire, KU Leuven and the Research Foundation – Flanders (FWO).

From left to right: Cis, Stefan, Myrthe, Andreas, Esmee and Dries.

The post Battle of the Scientists 2026 appeared first on Royal Observatory of Belgium.

Daunting image of a pair of stars and its surrounding nebula

Le Binh San Pham — Thu, 26 Feb 2026 15:35:23 +0000

Last Monday, the European Southern Observatory (ESO) released a new Picture of the Week. It is an image of a pair of stars and its surrounding nebula. The two stars constitute the binary system AFGL 4106, which was recently studied in a recent Astronomy and Astrophysics paper, of which René Oudmaijer of the Royal Observatory of Belgium is a co-author.

The binary system AFGL 4106 (black dots at the centre) and its surrounding nebula (in orange). Image taken with ESO’s Very Large Telescope (VLT). Credit: ESO/G. Tomassini et al.

The two stars, shown as a pair of black dots at the centre of the image, are an old stellar couple. As most stars are born in pairs, a big question for astronomers is: how does being in a couple impact a star’s death?

Before dying, stars expel huge amounts of gas and dust, ingredients for a growing nebula. The massive stars shown here are at close yet distinct late stages of their lifecycles, with one having blown off enough mass to produce a dusty surrounding envelope (shown in orange in the picture).

In a recent paper led by Gabriel Tomassini (Université Côte d’Azur, France) and of which René Oudmaijer is co-author, researchers have mapped this debris and precisely characterised the central stars.

Imaging astronomical objects close to stars poses a challenge due to the overpowering effect of a star’s brightness and, in fact, the stars themselves appear in black as their brightness saturated the detector of the instrument used to make this image.

Fortunately, the SPHERE instrument on the VLT is well equipped to deal with large contrasts in light levels, enabling a detailed study of both the high luminosity stars and the faint surrounding nebula for the first time. Moreover, it can correct the blur caused by atmospheric turbulence, delivering very sharp images.

The shape of the nebula reveals the significant impact the companion is having on the gas ejection of the dying star, introducing asymmetries and shifting the clouds of gas and dust away from a perfectly spherical shape. Further observations of star systems like this one allow scientists to better understand how the presence of companions affects the death of stars.

The ESO image release: https://www.eso.org/public/images/potw2608a/

The research paper

Tomassini et al., Characterising the post-red supergiant binary system AFGL 4106 and its complex nebula with SPHERE/VLT, Astronomy and Astrophysics, 706, A5, 13 pp., 2026. https://doi.org/10.1051/0004-6361/202557705

The post Daunting image of a pair of stars and its surrounding nebula appeared first on Royal Observatory of Belgium.

ROB and Belnet launch first span of Belgium’s resilient optical timing network

Le Binh San Pham — Wed, 21 Jan 2026 17:03:08 +0000

The Royal Observatory of Belgium (ROB) and Belnet are delighted to announce that – as part of the BOOSTED project – the first span of the Belgian time and frequency network is operational since December 4, 2025.

BOOSTED aims to develop an optical network for time and frequency transfer (T&F) in Belgium and connect it to the European metrology network. As the BOOSTED network is relying on optical links, it is insensitive to GNSS threats (like jamming, spoofing, …), supporting the development of resilient infrastructure.

This initial step enables already the delivery of an accurate timing signal, generated by the atomic clocks operated at the ROB, to 2 Belnet points-of-presence and 1 commercial data centre in the Brussels region. More specifically, the first 2 optical timing links are achieving an accuracy at the sub nanosecond level, making it more accurate than the timing signals currently generated by PTP and GNSS.

In the coming months, we will implement the next spans and will continue to connect users who have already expressed their desire to benefit from this service. If your organisation is also interested in joining the T&F network, be sure to register for the second time & frequency workshop, which will take place on March 10, 2026. This workshop, organised by the ROB and Belnet, will outline the progress made within the BOOSTED project and the steps that have already been taken in developing a sustainable T&F infrastructure in Belgium. Registration for this workshop is available via the following link: https://events.spacepole.be/event/269/.

The post ROB and Belnet launch first span of Belgium’s resilient optical timing network appeared first on Royal Observatory of Belgium.

Seismic Activity in/around Belgium in 2025

Le Binh San Pham — Mon, 05 Jan 2026 14:59:39 +0000

In 2025, 137 earthquakes were located by the Royal Observatory of Belgium in or near Belgium. On Belgian territory, no earthquake was large enough to have been felt.

In 2025, 137 natural earthquakes were measured by the Royal Observatory of Belgium in a zone between 1° and 8°E longitude and 49° and 52°N latitude (Figure 1). 37 natural earthquakes were located on Belgium territory, although none of these events were felt by the local population as either these earthquake’s magnitudes were too small, or their focal depths were too deep. The largest earthquake in Belgium occurred on 31 December 2025 in Heppenbach and had a local magnitude of M_L=1.7. The 2025 ROB catalogue is complete for natural earthquakes with a magnitude M_L larger than 1.0. Events with magnitudes lower than 1.0 were also routinely detected where the Belgian seismic network is denser on the Belgian property. Outside Belgium, only those events that were large enough to be detected by the Belgian seismic network were included in the 2025 seismic catalogue. Most earthquakes recorded in 2025 occurred in regions with documented historical seismic activity (Figure 2).

In 2025, the Royal Observatory of Belgium (ROB) also measured four induced events, 307 quarry blasts and 4 explosions offshore linked to controlled explosions of WW1 and WW2 bombs by the Belgian, Dutch or French Armies.

In comparison, last year in 2024, 141 earthquakes were detected in and around Belgium.

Figure 1: Events recorded in 2025 by the Belgian Seismic Network of the Royal Observatory of Belgium. 37 earthquakes occurred on Belgian territory.

Figure 2: Earthquakes recorded in 2025 by the Belgian Seismic Network of the Royal Observatory of Belgium. The full Belgian seismic catalogue is shown in white. Earthquakes measured in 2025 occurred in regions with documented historical seismic activity.

Website: https://seismologie.be/en

The post Seismic Activity in/around Belgium in 2025 appeared first on Royal Observatory of Belgium.

Proba-3 is 1 year in space

Le Binh San Pham — Tue, 09 Dec 2025 16:36:34 +0000

December 5, 2024 – 1 year ago, the duo satellite Proba-3 left Earth to head to space. The telescope ASPIICS, whose task is to make perfect total solar eclipses from space, was onboard. The launch went flawless.

December 5, 2025 – exactly 1 year later, ASPIICS has already delivered a wealth of amazing pictures of the solar atmosphere close to its surface, a treasure box for solar scientists.

A peek in the treasure box

The picture below is a white-light image of the solar corona taken by ASPIICS on September 9, 2025. The corona has a shape typical for a maximum in the solar activity cycle, with streamers visible all around the solar limb. A Coronal Mass Ejection is seen propagating towards the west (right in the image).

Credit: ESA/Proba-3/ASPIICS

The next image/video shows the Sun and the solar atmosphere on July 16, 2025. The green images are more detailed compared to the red images. A Coronal Mass Ejection is seen propagating towards the west (right in the image). The middle EUV image is taken by SDO/AIA. The green white-light image is taken by ASPIICS, the red white-light image is from SOHO/LASCO.

Click on the image to get the movie. Credit: ESA/Proba-3/ASPIICS.

Reactions from a few people of the Belgian ASPIICS team

Laurent Dolla, Science Planner – one can never get bored

ASPIICS is really a cutting-edge instrument, for which I plan the observations. Our images are ‘clean’ and of exceptional good quality. It was a surprise that the instrument achieves this even with “normal” exposure times. We can now see features that were never seen before because they clearly stand out from the background. For us, solar scientists, this is very exciting. When I wake up in the middle of the night, it’s not uncommon that I start working. With ASPIICS, one can never get bored.

Andrei Zhukov, Principal Investigator – being on the forefront of solar physics

I joined the Proba-3 team already in 2009. Now, after launch and commissioning, I can finally do what I love to do: science. We make total solar eclipses, almost as on an assembly line, which feels for me as being a kid on a science playground toying with unprecedented images. In June 2025, I witnessed the first huge prominence eruption with ASPIICS. We could already see it in our images before they were even cleaned! I’m looking forward to presenting the science results at the annual meeting of the American Geophysical Union in December 2025.

Zoe Zontou, Instrument Operator – this is the coolest job ever

It is so cool that we make total solar eclipses from space and I’m an operator of this instrument! I come from a totally different background than solar physics, so I was thrilled when I joined the team in May 2025. The day that we showed the first official science image to the public was really exciting. I already learned so many things about the solar atmosphere. ASPIICS showed me that I will never stop asking questions and never stop learning. I love it and look forward to meeting even more interesting people and discovering more on solar physics and our Sun!

Andreas, Instrument Operator – bitten by the heliophysics bug

I plan and write commands for the telescope, but I also do surveillance of the newly arrived data. This means that I’m one of the first taking a glimpse at the images! I’m really on the front line to see things which were never seen before. The commanding of ASPIICS can in theory be done a bit beforehand, but in the early phases of the mission I was sometimes at the Mission Operations Center in Redu where I had to take immediate action and call to remote ground stations. Together we had to command the satellites and ASPIICS in real-time. Since my PhD, I have had big dreams. Now, it is amazing to be part of this passionate researchers community and figure out important open questions on the Sun.

Late growth spurt of young stars allows giant planets to form after all

Le Binh San Pham — Wed, 03 Dec 2025 16:49:32 +0000

Brussels, 3 December 2025 – By measuring the rate at which young stars grow, astronomers discovered that contrary to earlier expectations, young stars appear to grow much faster in the later stages of their formation than at the onset. So, much like humans, intermediate mass stars undergo a growth spurt and have a voracious appetite during their adolescence. This finding, reported by an international team led by Sean Brittain of Clemson University USA, and including René Oudmaijer of the Royal Observatory of Belgium, solves a long-standing problem with giant planets that are routinely detected around stars of intermediate mass, but should not exist.

Young stars begin their life surrounded by a disk of gas and dust. Over the past 40 years, astronomers have established that the material in this disk gradually falls onto the young star as it grows and matures. The disk is ionized by radiation from the star, which causes it to spread, like a mound of clay on a potter’s wheel. Some of this material falls onto the star, some is blown away, and some of it forms into planets. As the disk dissipates, the rate at which material falls onto the star decreases as well. Ultimately the star reaches its final mass and further planet formation comes to a halt.

This image combines data from Webb’s near- and mid-infrared observations of the Pillars of Creation, including thousands of stars that show up in near-infrared light, and all the dust that pops out in mid-infrared light.
NASA, ESA, CSA, STScI; Image Processing: Joseph DePasquale (STScI), Alyssa Pagan (STScI), Anton Koekemoer (STScI). Source: https://science.nasa.gov/asset/webb/pillars-of-creation-nircam-and-miri-composite-image/

This theory does a very good job at explaining the formation of stars similar to the Sun, but it has been challenged by the observations of young stars that are slightly more massive. These stars were found to be gaining mass at much higher rates than expected.

How can astronomers measure the growth rate of stars? As Professor Sean Brittain explains, ‘When material falls onto a star, a lot of energy is released, just like when you drop a chair it will make a noise or even break. In the case of material being accreted, the energy released is much greater. We can see this as extra radiation coming from the system, and this allows us to determine the rate at which the stars grow in mass.’

The team studied young stars, also referred to as Herbig stars that are hotter and more massive than our Sun. Their accretion rates were already well studied and – as expected – observed to decrease with age as the stars reach their full maturity. However, it also meant that in their earlier phases, the stars must accrete at even higher rates than observed now.

Team member Dr René Oudmaijer, from the Royal Observatory of Belgium, says, ‘This implied that the disks surrounding these stars must start out to be very massive indeed. This would pose a problem because such massive disks would be unstable and break up before planets even have the chance to be formed.’

Recent surveys identified stars that would evolve into Herbig stars which prompted the team to study how the accretion rates of these younger objects would differ from those of the Herbig stars. What they found was unexpected as team member Dr Gwendolyn Meeus of the Universidad Autónoma de Madrid in Spain comments: ‘Instead of higher accretion rates, we found values that were up to 30 times lower than those of the Herbig stars. In a way this would solve the mass problem, as the disk does not need to be so massive to begin with.’ But this posed yet another problem as Brittain continues: ‘Theory would predict that the stars accrete less material over time, not more. This new finding needs an explanation based on well-grounded physics if we are to change our current thinking.’

The team found that there was one key ingredient missing in the models so far. The so-called Herbig stars have high temperatures, but their precursors start out much cooler. It is precisely the stellar temperatures that affect the disks and determine how quickly they lose their material to the star. A star that gets hotter will gradually emit much more ultraviolet radiation. This in turn ionizes the gas in the circumstellar disks, which then results in an increasingly larger accretion onto the star.

The long-standing mystery that gas giant planets around intermediate mass stars were observed, but not predicted to exist, appears to be solved with this work. ‘Indeed,’ as team member Josh Kern of Clemson University concludes, ‘this unexpected late growth spurt opens up the possibility for giant planets to be formed in the earlier stages, when the stars are still much cooler, after all.’

The findings are published in the Astronomical Journal.

The article:
Brittain et al., ‘Evolution of the Accretion Rate of Young Intermediate Mass Stars: Implications for Disk Evolution and Planet Formation’ The Astronomical Journal, DOI: 10.3847/1538-3881/ae1a42, published online.

The post Late growth spurt of young stars allows giant planets to form after all appeared first on Royal Observatory of Belgium.

Northern Lights Over Belgium

Le Binh San Pham — Wed, 12 Nov 2025 15:38:48 +0000

November 12, 2025, very early in the morning. Colleagues from the STCE, the Belgian Space Weather Centre, admired the northern lights from their terrace in Brussels and are amazed by the show of colours. After all, it is quite exceptional to be able to observe this phenomenon in Belgium (let alone in the middle of a city with a lot of light pollution), even if our Sun is now in the most active phase of its cycle.

Image credits: Nancy Narang (Royal Observatory of Belgium).

Indeed, the Sun is the cause of these northern lights. In recent days, our Earth has been in the sights of a very active solar region. This region produced several solar flares of the highest category (X). These were accompanied by eruptions of solar plasma and protons, which are very fast particles. The successive plasma clouds were directed toward Earth and were launched with increasingly higher speeds.

Stormy Nights

Last night, the first of these solar clouds arrived at Earth. They caused very strong disturbances in our magnetic field. This is measured using ground-based instruments called magnetometers, which, for Belgium, we have installed in Dourbes and Manhay. Based on these measurements, a local K-index is compiled that reflects the disturbance of the magnetic field in our region. A local K > 8 indicates the possibility of visible northern lights. The graph below clearly shows that this condition was met last night.

Magnetic Activity Indices for Belgium (source)

Should we be concerned?

The northern lights are primarily a beautiful spectacle to be enjoyed to the fullest, but a geomagnetic storm can affect our technology. In addition to the geomagnetic field, they also disrupt the ionosphere, a layer in our atmosphere that is crucial for communication. Last night, warnings were sent to the aviation industry to alert them to disruptions in their radio communications. GPS positioning may also be slightly less accurate during a storm. In countries closer to the poles, disruptions can occur in the electricity grid. Network operators and the Defence forces in our country were therefore also notified. The STCE is monitoring the situation closely.

What can we expect next?

Yesterday, on November 11, this active region launched the most recent solar flare and plasma cloud. This cloud left the sun at a speed of more than 1500 km per second and is now racing through space toward Earth. We estimate it will reach us tonight. We can therefore expect additional disruption to our magnetic field. Space weather will thus remain stormy for a few more days.

In addition, the sun is still very active and the area causing all the disturbances is still facing Earth. New solar flares and plasma clouds cannot be ruled out. The STCE forecasters are facing a busy week. And if we are lucky, we may also see the northern lights tonight, as long as the clouds do not spoil the show: look north!

The post Northern Lights Over Belgium appeared first on Royal Observatory of Belgium.

Scientists of the Bepicolombo mission met at the Royal Observatory of Belgium

Le Binh San Pham — Mon, 13 Oct 2025 11:18:31 +0000

Tuesday, September 30, 2025, marked the beginning of a 3-day workshop gathering international members from the BELA and MORE experiments onboard the BepiColombo mission to Mercury.

The joint ESA and JAXA mission was launched in 2018 and is about to reach the end of its long voyage to Mercury where it is slated to insert into orbit at the end of 2026. Scientists are now actively perfecting all the necessary tools and techniques to make the most of the forthcoming measurements and scientific data, which will offer an unprecedented window into the elusive interior of the planet.

The Mercury Orbiter Radio-science Experiment (MORE) onboard BepiColombo will measure Mercury’s gravity field, including small temporal variations, for example due to tides. The BepiColombo Laser Altimeter (BELA) will map the surface of the planet with groundbreaking accuracy and will determine subtle motions caused by tides and rotation. The data from both these experiments will allow scientists, among which several from the Royal Observatory of Belgium (ROB), to infer properties of the planet’s deep interior.

Scientists from the ROB also participated in another meeting on BepiColombo at the Paris Observatory on Thursday and Friday of the same week. Members of the SIMBIO-SYS team, the spectrometer and camera of BepiColombo, discussed the latest advances in the preparation of the data analysis. By precisely measuring the rotation of Mercury, SIMBIO-SYS will complement data from MORE and BELA to probe the deep interior of Mercury.

Van Hoolst is Co-I of MORE, Co-I of SIMBIO-SYS, team member and WG lead of BELA
Rivoldini is Co-I and WG lead of BELA
Yseboodt, R.-M. Baland, and J. Rekier are team members of BELA

The post Scientists of the Bepicolombo mission met at the Royal Observatory of Belgium appeared first on Royal Observatory of Belgium.