arXiv subjects

Astrid M. Veronig

Publications and source records attributed to Astrid M. Veronig.

At least 19 recordsLinked to original sources

arXiv2026

Solar Soft X-ray Coronal Dimming in a Failed Eruption Associated with Plasma Cooling

Coronal dimmings are observed as sudden and localized reductions in the extreme-ultraviolet and X-ray emission of the solar corona. Traditionally, significant dimmings of spectral lines formed at temperatures of 1-2 MK are regarded as indicators of coronal mass ejections (CMEs), reflecting the density depletion caused by plasma escaping into interplanetary space. In this Letter, we report a peculiar deep coronal dimming event predominantly observed in high-temperature spectral lines following an M8.8-class confined solar flare associated with a failed filament eruption. Sun-as-a-star measurements from the Geostationary Operational Environmental Satellite and the Extreme Ultraviolet Variability Experiment reveal intensity reductions exceeding 30% in soft X-ray (SXR) and measurable decreases in Fe XVIII (6.5 MK) and Fe XX (9.3 MK). Spatially resolved observations from the Atmospheric Imaging Assembly demonstrate that the dimming originates from the active region core, while the Solar Terrestrial Relations Observatory-A shows no evidence for CME-driven mass loss. Differential emission measure analysis reveals plasma at temperatures >5 MK cooling into lower temperatures, supporting plasma cooling as the dominant contributor to the hot-band dimming rather than CME-associated plasma escape. This event demonstrates that deep hot SXR dimmings can occur without substantial CME-driven mass loss, suggesting that alternative physical mechanisms may also account for unresolved stellar dimmings in addition to the commonly inferred CME signatures.

astro-ph.SR↗

arXiv2026

Comprehensive solar eruption analyses enabled by the tools of the SOLER project

Solar eruptions comprise of a multitude of phenomena such as flares, coronal mass ejections (CMEs), large-scale coronal waves, radio bursts, and energetic particles traveling through interplanetary space. These phenomena are observed with a variety of instrumentation, including remote sensing and in-situ detectors. Obtaining a global understanding of a solar eruption often requires the analysis of various of these different datasets, including a multitude of analysis and modeling tools and a wide range of expertise. Usually, such a comprehensive analysis can only be achieved by a skilled and broad team. The Energetic Solar Eruptions: Data and Analysis Tools (SOLER) project aims at creating a comprehensive analysis platform for the study of solar eruptions that allows a single user to easily apply analysis methods addressing various counterparts of the solar event. Therefore, each partner of the project developed Python-based software, including interfaces in the form of Jupyter Notebooks, which provides application examples and concise step-to-step documentation. In this paper we introduce the comprehensive solar-eruption-analysis infrastructure developed within the SOLER project. We explain where to find the software, how to use it, and give dedicated use-case examples of how to employ selected tools in a combined manner.

physics.space-ph↗

arXiv2026

ESCAPE: a small explorer mission to study the stellar drivers of exoplanet evolution

The long-term stability of exoplanetary atmospheres depends critically on the extreme-ultraviolet (EUV) photon and high-energy particle fluxes from the host star, which are poorly constrained. To address this key gap in our understanding of atmospheric retention, we present the Extreme-ultraviolet Stellar Characterization for Atmospheric Physics and Evolution (ESCAPE) mission, a NASA Small Explorer concept proposed in 2026. ESCAPE employs extreme- and far-ultraviolet spectroscopy (80 - 1650 Ang) to provide the first comprehensive study of the stellar EUV history and stellar coronal mass ejection (CME) environments that control atmospheric mass-loss and determine the habitability of rocky exoplanets. This paper outlines both the primary science goals of the mission, the breadth of future general observer investigations, and a detailed design study of the mission's instrumentation. The ESCAPE instrument comprises a grazing incidence telescope that feeds multiple diffraction gratings and a photon-counting detector. We describe a demonstration of the Hettrick-Bowyer telescope, etched silicon diffraction gratings, the microchannel plate detector and housing, and gold and zirconium coatings. We present a STOP analysis that verifies ESCAPE's ability to meet its structural integrity, thermal stability, and optical performance requirements throughout the mission environment.

astro-ph.EP↗

arXiv2026

DEM analysis of the 6 September 2011 large-scale coronal wave

Large-scale coronal waves are globally propagating intensity enhancements in extreme-ultraviolet (EUV) and soft X-ray (SXR) observations, associated with solar flares and coronal mass ejections (CMEs). They are interpreted as low-coronal signatures of a large-amplitude fast magnetosonic wave. On 6 September 2011, a fast (v = 1000 km/s) large-scale coronal wave accompanied an eruptive X2.1 class flare. A segment of the wave front temporarily dissappeared in EUV channels sensitive to quiet-Sun plasma, while it remained visible in higher temperature channels. We apply differential emission measure (DEM) diagnostics to SDO/AIA EUV observations to derive local density, temperature, emission measure, and DEM distributions, and examine their temporal evolution during the wave passage. The wave passage causes increases of 6-8% in density and 10-18% in temperature. While the density increase is comparable to earlier reports, the temperature increase exceeds expectations. This indicates that the temperature enhancement cannot be explained by compressional adiabatic heating alone, and instead suggests the presence of additional heating mechanisms, such as magnetic reconnection or wave mode conversion. During the temporary disappearance of the wave, the plasma parameters at the wave front increase, but with a strong spatial variability, with density increases ranging from 1% to 10%. The initial temperature in the affected area is notably higher than typical quiet-Sun regions (T > 1.7 MK), which allows plasma to be heated beyond the peak response of the AIA 193 and 211 Åchannels. We conclude that the apparent temporary disappearance of the wave front is primarily due to the combined effects in the intensity of the CME-associated coronal dimming following the wave and the wave itself, with heating further reducing its detectability in channels sensitive to quiet-Sun temperatures.

astro-ph.SR↗

arXiv2026

Investigation of the Two-Dimensional Velocity Field of the Large-Scale Coronal Wave from September 6, 2011 using the SOLERwave Tool

We investigate the two-dimensional velocity field of the fast and complex large-scale coronal wave observed on September 6, 2011. We use both a classical perturbation profile approach and the newly developed multi-sector method of the SOLERwave tool, using a Huygens-plotting-based approach. The multi-sector method utilizes perturbation profiles derived in multiple directions (sectors) to determine the location of the wavefront at a given time. The two-dimensional velocity vector at each point along the wavefront is derived by identifying the point closest to it along the wavefront observed one time step earlier and dividing the distance between the two points along the solar surface by the time difference between the observations. For the event under study the resulting two-dimensional velocity field shows a significant difference between the northward traveling and the northwest ward traveling part of the wave front of over 40%, in the range of 750 to 1500 km/s. To determine the cause of this difference in speed, we investigate the coronal structures, the photospheric magnetic field distribution and the Alfvén speed derived from a steady-state coronal magneto hydro dynamic (MHD) solution along different propagation directions of the wave. We find the large difference in magnetosonic speed found in the investigated sector as the most likely explanation for the velocity difference.

astro-ph.SR↗

arXiv2026

A single power law for the TRAPPIST-1 flare distribution across four orders of magnitude in energy

TRAPPIST-1 is an ultra-cool dwarf that flares frequently. These flares shape the surrounding planets' high-energy irradiation environments, with consequences for atmospheric chemistry and escape, and they can contaminate transmission spectroscopy of those planets. A quantitative flare-frequency distribution (FFD) spanning the full energy range is therefore essential for both interpreting JWST spectra and modeling the planets' irradiation histories. Here we present a unified FFD over four orders of magnitude in energy by jointly analyzing $\approx$87\,hr of JWST/NIRISS and JWST/NIRSpec time-series spectroscopy together with $\approx$74\,days of \textit{Kepler}/K2 photometry. To enable a consistent comparison across these heterogeneous datasets, we convert all events to energies in the TESS bandpass. For the Kepler-to-TESS conversion we adopt a cooler flare continuum appropriate for ultra-cool dwarfs ($T_{\rm flare}=3500$\,K). After correcting for flare-detection sensitivities, the combined JWST+K2 cumulative FFD is consistent with a single power law, $N(\ge E_\mathrm{TESS})\propto E_\mathrm{TESS}^{-β}$, with $β=0.753$ over $E_{\rm TESS}\simeq10^{29}$-$10^{33}$\,erg. The slope of the distribution indicates that the time-averaged flare energy budget is dominated by rare, high-energy events rather than by the more numerous low-energy flares. Moreover, we found that strong flares with energies $E_\mathrm{TESS} > 10^{32}$~erg occur once every 25 days, about an order of magnitude more frequently than inferred from previous TRAPPIST-1/analog FFD estimates. This elevated rate of energetic flares has important implications for atmospheric escape, photochemistry, and habitability assessments of the TRAPPIST-1 planets.

astro-ph.SR↗

arXiv2026

Multi-Viewpoint Observation of a Failed Prominence Eruption on the Sun

Solar eruptions are sudden ejections of coronal mass and magnetic fields accompanied by intense energy release. The eruptive structure does not always erupt successfully, but sometimes fails to escape the Sun after initiation. The failure of an eruption, however, provides an invaluable opportunity for understanding the intricate mechanism of eruptions. We present a comprehensive observation of a failed prominence eruption on the Sun, taking advantage of multi-viewpoint and multi-messenger imaging. Simultaneous off-limb and on-disk observation gives evidence of magnetic reconnection processes occurring at different sites during the flare. Particularly, in addition to the standard flare reconnection behind the eruption, strong external reconnection occurs on the erupting flux rope, evidenced by a wealth of signatures via multi-wavelength imaging and spectroscopy. The two reconnection processes may play contrasting roles in the flux rope's acceleration and compete in altering the magnetic flux in the rope. As the high rate of external reconnection proceeds, the flux rope and embedded prominence decelerate noticeably and fail to erupt into the heliosphere, under strong magnetic confinement of overlying fields. Our results illustrate a well-defined physical picture for solar eruptive activities and provide insight into the lack of coronal mass ejections found in other solar-type stars.

astro-ph.SR↗

arXiv2026

Magnetic flux systems involved in the May 2024 solar energetic events from AR 13664 inferred through coronal dimmings

Coronal dimmings are transient depletions of coronal plasma observed in extreme ultraviolet and soft X-rays, interpreted as low-corona signatures of coronal mass ejections (CMEs). Their evolution is closely linked to CME dynamics, flare reconnection, and large-scale coronal magnetic restructuring. In May 2024, active region (AR) 13664 produced 66 > M-class flares and multiple fast CMEs that caused the strongest geomagnetic storm since 2003. We analysed 16 on-disc dimmings observed in SDO/AIA 211Ådata between May 1-14, 2024. We extracted dimmings using logarithmic base-ratio thresholding, and derived magnetic properties from SDO/HMI line-of-sight magnetograms. We identified flare ribbons in AIA 1600Ådata via adaptive thresholding, and computed reconnection fluxes from radial magnetic field maps. We examined the magnetic flux systems involved in the eruptions using PFSS and NLFF extrapolations. We found correlations between dimming and flare ribbon properties stronger than previously reported. The dimming morphology evolved systematically, with southward expansion before May 9 and northward afterward, coinciding with a shift in flare ribbon locations between two mayor east-west polarity inversion lines (PILs). These changes imply the presence of two distinct magnetic domains. The PFSS extrapolations showed that southward (northward) dimmings are mainly strapping flux dimmings with magnetic field lines vaulting above the southern (northern) PIL. The final extent of the dimmings was then given by the exterior flux involved in the eruption via stretching and reconnection. One event revealed an extended quiet-Sun dimming likely triggered by EUV wave-induced field opening.

astro-ph.SR↗

arXiv2026

Neural blind deconvolution to reconstruct high-resolution ground-based solar observations

Ground-based solar observations enable unprecedented spatial, spectral, and temporal resolution of the lower solar atmosphere, yet Earths turbulent atmosphere imposes significant limitations, requiring advanced post-facto image reconstruction. State-of-the-art reconstruction methods are based on restoring a burst of short exposure frames to a single observation. Limitations of these techniques arise due to the sparse information about the atmospheric point spread function (PSF) that degrade the observations and consequently the quality of reconstructions. We develop a novel image reconstruction method to achieve unprecedented spatial resolution from short exposure image bursts. This can provide high-quality reconstructions and therefore advance the study of the smallest spatial scales from the solar photosphere to the chromosphere. In this study, we present a novel approach for high-resolution solar image reconstruction based on physics-informed neural networks. In the training process, the neural network maps coordinate points directly to their corresponding intensity values while simultaneously updating the PSF parameters. The method convolves the true object from the neural network with the estimated PSFs and optimizes the network by minimizing the loss between the synthesized and real short-exposure image burst. This approach enables the simultaneous estimation of both the degrading PSF and the real high-resolution intensity distribution. We demonstrate the method on synthetic intensity data derived from a radiative MHD simulation and apply it to high-resolution observations from GREGOR and DKIST. Our results demonstrate the ability to reconstruct small-scale solar features that exceed the reconstruction performance of state-of-the-art reconstruction methods. With this approach we lay the foundation for future spatially varying PSFs.

astro-ph.SR↗

arXiv2025

Height and Energy Evolution of X-ray Double Sources in a Solar Flare

In the standard model, magnetic reconnection at a vertical current sheet above the flare arcade is key to explaining many aspects of solar eruptions. The supra-arcade region is where the vertical current sheet is supposedly located, and X-ray/EUV emission therein reflects underlying energy release and transport processes, therefore providing valuable insight into the structure and evolution of the current sheet. Previous studies have focused primarily on the impulsive phase of flares, but phenomena in the decay phase are also crucial for understanding the complete flaring scenario. In this paper, we investigated an M6.7-class limb flare that occurred on August 28, 2022, combining observations from the Solar Orbiter (SolO) and Solar Dynamics Observatory (SDO). Coronal X-ray sources are continually observed by the Spectrometer/Telescope for Imaging X-rays (STIX) onboard SolO for over two hours, revealing a multi-phase evolution with varying velocities and multiple substructures, with higher-energy components consistently appearing at higher altitudes. Such a height-energy relation is notably observed in a double coronal source during the decay-phase, which is dominated by thermal emission. The energy distribution of the double source distinguish itself from previous studies that showed a symmetric distribution, with the higher-energy components being closer to the center of the double source during the impulsive phase. Obtained from two opposite side-on perspectives on the supra-arcade region, these findings reveal the spatio-temporal complexity of the energy release process in the post-flare current sheet during the decay phase.

astro-ph.SR↗

arXiv2025

Extreme ultraviolet late-phase flares as observed by EVE and AIA on board the Solar Dynamics Observatory

Context. Extreme ultraviolet (EUV) late-phase (ELP) flares exhibit a second peak in warm coronal emissions minutes to hours after the main peak of the flare. This phase is all but negligible, and it is still poorly understood what role it plays across the solar cycle and what governs it. Aims. We present a statistical analysis of ELP flares over four years between May 2010 and May 2014 based on properties such as eruptivity, magnetic configuration, and late-phase duration, delay, and strength in order to understand what influences the likelihood of this class of flares and their behavior on a general scale. Methods. We primarily made use of data from the Solar Dynamics Observatory (SDO) Extreme ultraviolet Variability Experiment (EVE), as well as complementary spatial information provided by the Atmospheric Imaging Assembly (AIA), to assess relationships between the various parameters and to see if ELP flares differ from the general flare population. We quantified the criteria for ELP flare definition and determined the characteristics of the flares. Results. Our analysis shows that about 10\% of all flares with a GOES class $\geq$C3.0 experience an EUV late phase (179 out of 1803). This percentage decreases from solar minimum to solar maximum. C-class flares are considerably less likely to be identified as ELP flares than their higher-energy counterparts, which is in line with previous investigations. The majority of this type of flare are confined (67%), more so than in the general flare population ($\geq$C5.0). There appears to be a (linear) relationship between the late-phase delay and its duration. The ratio of the emission peak of the late and main flare phase lies between 0.3 and 5.9, and exceeds 1 in 71.5% of cases, which is considerably higher than previously reported.

astro-ph.SR↗

arXiv2025

An analysis of the solar differential rotation in solar cycle No. 19 (1954-1964) determined using Kanzelhoehe sunspot group positions

We study solar differential rotation (DR) for solar cycle No. 19 (1954-1964) by tracing sunspot groups on the sunspot drawings of Kanzelhoehe Observatory for Solar and Environmental Research (KSO). Our aim is to extend previous DR analysis from the KSO data (1964-2016) to the years prior to 1964 to create a catalog of sunspot group positions and DR parameters from KSO sunspot drawings and white light images. Synodic angular rotation velocities were first determined using the daily shift (DS) and robust linear least-squares fit (rLSQ) methods, then converted to sidereal velocities, and used to derive solar DR parameters. We compare the DR parameters obtained from different sources and analyse the north-south asymmetry of rotation for solar cycle No. 19. It has been shown that our results for the equatorial rotation velocity (parameter A) and the gradient of DR (parameter B) coincide with earlier results from the KSO data (performed with a different method), as well as with results from the Kodaikanal Solar Observatory (KoSO) and the Yunnan Observatories (YNAO). In contrast, the values of parameter A from three different earlier studies based on the Greenwich Photoheliographic Results (GPR) exhibit statistically significant differences when compared to the values of parameter A derived from KSO, KoSO and YNAO. These findings suggest that the GPR data have the largest inconsistency compared to the other three data sources, highlighting the need for further analysis to identify the causes of these discrepancies. The analysis of the north-south asymmetry in the solar rotation profile using two different methods shows that the DR parameters of the hemispheres coincide, indicating a rotational symmetry around the equator. This is consistent with previous results from KSO and YNAO data. However, all sources indicate slightly higher equatorial rotation velocities in the southern hemisphere.

astro-ph.SR↗

arXiv2025

Coronal mass ejection arrival forecasting with the drag-based assimilation of satellite observations

Forecasting the arrival of coronal mass ejections (CMEs) is vital for protecting satellites, power systems, and human spaceflight. We present HELIOPANDA: Heliospheric Observer for Predicting CME Arrival via Nonlinear Drag Assimilation, a framework that integrates the Drag-Based Model (DBM) with spacecraft observations using iterative parameter estimation and Kalman filter assimilation. We introduce a method for estimating the solar wind speed $w$ and drag parameter $γ$, two key but usually unknown quantities controlling CME propagation, through direct solutions of the DBM equations. We tested the method on 4,480 synthetic CME profiles spanning CME speeds of $200-3500$ km/s, solar wind speeds of $250-800$ km/s, and drag parameters of $0.1-1.0\times10^{-7}$ km$^{-1}$. The results demonstrate that the framework provides accurate reconstructions of the DBM input parameters, providing a solid basis for in-situ and remote-sensing applications. By testing a single virtual spacecraft positioned at nine distances along the Sun-Earth line, HELIOPANDA achieved arrival-time errors as low as 0.6 hours for a 600 km/s CME and 1 hour for a 2500 km/s CME when the spacecraft was located 30 million km from the Sun. We developed a Kalman filter framework to assimilate noisy heliospheric data into the DBM, enabling recursive updates of CME kinematics and robust estimates of $w$ and $γ$, and yielding Earth and Mars arrival-time predictions within $1-2$ hours using 160 simulated hourly measurements. By combining DBM, parameter recovery, and data assimilation, HELIOPANDA provides a pathway to real-time, multi-point CME forecasts, suited to observations from Solar Orbiter, Parker Solar Probe, PUNCH, and planned L4/L5 missions.

astro-ph.SR↗

arXiv2025

Image calibration between the Extreme Ultraviolet Imagers on Solar Orbiter and the Solar Dynamics Observatory

To study and monitor the Sun and its atmosphere, various space missions have been launched in the past decades. With the rapid improvement in technology and different mission requirements, the data products are subject to constant change. However, for long-term studies such as solar variability or multi-instrument investigations, uniform data series are required. In this study, we build on and expand the Instrument-to-Instrument translation (ITI) framework, which provides unpaired image translations. We apply the tool to data from the Extreme Ultraviolet Imager (EUI), specifically the Full Sun Imager (FSI) on Solar Orbiter (SolO) and the Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory (SDO). This approach allows us to create a homogeneous data set that combines the two extreme ultraviolet (EUV) imagers. We demonstrate that ITI is able to provide image calibration between SolO and SDO EUV imagers, independent of the varying orbital position of SolO. The comparison of the intercalibrated light curves derived from EUI and AIA shows that ITI can provide uniform data series that outperform a standard baseline calibration. We evaluate the perceptual similarity in terms of the Fréchet Inception Distance (FID), which demonstrates that ITI achieves a significant improvement of perceptual similarity between EUI and AIA. The study provides intercalibrated observations from SolO/EUI/FSI with SDO/AIA, enabling a homogeneous data set suitable for solar cycle studies and multi viewpoint investigations.

astro-ph.SR↗

arXiv2025

Magnetic structure and asymmetric eruption of a 500 Mm filament rooted in weak-field regions

We performed a detailed analysis of the magnetic structure and asymmetric eruption of a large (about 500 Mm) inverse S-shaped filament partially located in AR 13229 on February 24, 2023. We linked the filament's pre-eruptive magnetic configuration to its highly asymmetric eruption dynamics and the formation of a large-scale coronal dimming in a weak-field region (mean unsigned flux of about 5 G). To reconstruct the coronal magnetic field, we applied a physics-informed neural network (PINN)-based nonlinear force-free field (NLFFF) extrapolation method to a pre-eruption HMI vector magnetogram. The NLFFF extrapolation reveals a large-scale magnetic flux rope (MFR) of about 500 Mm in length, consistent with the filament. We identified an extended MFR footprint to the east that connects to the J-shaped flare ribbon, outlining where the coronal dimming began. Overlying strapping fields connect to the area into which the dimming and flare ribbon later expand. This configuration explains the formation of the dimming as a stationary flux rope and strapping flux dimming, with subsequent expansion driven by the growth of the MFR footprint through strapping-strapping reconnection. Conversely, the western filament leg shows multiple anchor points and strong overlying magnetic fields, which suppressed the dimming and partially confined the eruption on that side. The reconstructed pre-eruptive NLFFF configuration offers a clear physical explanation for the asymmetries seen in the eruption, flare geometry, and coronal dimming. This demonstrates that PINN-based NLFFF extrapolation can effectively model large-scale filaments extending into weak-field regions, enhancing our understanding of complex solar eruptions.

astro-ph.SR↗

arXiv2025

Flares on TRAPPIST-1 reveal the spectrum of magnetic features on its surface

TRAPPIST-1 is an M8 dwarf hosting seven known exoplanets and is currently one of the most frequently observed targets of the James Webb Space Telescope (JWST). However, it is notoriously active, and its surface is believed to be covered by magnetic features that contaminate the planetary transmission spectra. The radiative spectra of these magnetic features are needed to clean transmission spectra, but they currently remain unknown. Here, we develop a new approach for measuring these spectra using time-resolved JWST/NIRISS observations. We detect a persistent post-flare enhancement in the spectral flux of TRAPPIST-1. Our analysis rules out lingering flare decay as the cause of the flux enhancement and, thus, points to structural changes on the stellar surface induced by flares. We suggest that the flaring event triggers the disappearance of (part of) a dark magnetic feature, producing a net brightening. This suggestion is motivated by solar data: flare-induced disappearance of magnetic features on the solar surface has been directly detected in high spatial resolution images, and our analysis shows that this process produces changes in solar brightness very similar to those we observe on TRAPPIST-1. The proposed explanation for the flux enhancement enables, to our knowledge, the first measurement of the spectrum of a magnetic feature on an M8 dwarf. Our analysis indicates that the disappearing magnetic feature is cooler than the TRAPPIST-1 photosphere, but by at most a few hundred kelvins.

astro-ph.EP↗

arXiv2025

Detecting Stellar Coronal Mass Ejections via Coronal Dimming in the Extreme Ultraviolet

Stellar flares and coronal mass ejections (CMEs) can strip planetary atmospheres, reducing the potential habitability of terrestrial planets. While flares have been observed for decades, stellar CMEs remain elusive. Extreme ultraviolet (EUV) emissions are sensitive to both flares and CME-induced coronal dimming. We assess the detectability of stellar CME-induced EUV dimming events by adapting a known "Sun-as-a-star" dimming technique -- validated by the Solar Dynamics Observatory's EUV Variability Experiment (EVE) -- to stellar conditions. We adapt the solar data to reflect a range of stellar intensities, accounting for intrinsic brightness, distance, and interstellar medium (ISM) attenuation. We generate synthetic light curves for two different missions: the legacy EUV Explorer (EUVE) and the proposed ESCAPE mission. Our results indicate that dimming detections are well within reach. EUVE's broadband imager was capable of detecting stellar CMEs -- albeit with limited spectral (temperature) resolution -- but that was not part of the observing plan. EUVE's spectroscopic survey lacked sufficient sensitivity for CME detections. Optimizing modern instrument design for this task would make the observation fully feasible. In this work, we present a tool to explore the stellar-CME detection parameter space. Our tool shows that an instrument with performance similar to ESCAPE, setting a 600-second integration period, and integrating the spectra into bands, any star with an X-ray flux $\geq 2.51 \times 10^{-12}$ergs$^{-1}$~cm$^{-2}$ should have a $\geq 3σ$ detection even for a modest few-percent dimming profile, regardless of ISM attenuation. Such measurements would be crucial for understanding the space weather environments of exoplanet host stars and, ultimately, for evaluating planetary habitability.

astro-ph.SR↗

arXiv2025

Deep learning image burst stacking to reconstruct high-resolution ground-based solar observations

Large aperture ground based solar telescopes allow the solar atmosphere to be resolved in unprecedented detail. However, observations are limited by Earths turbulent atmosphere, requiring post image corrections. Current reconstruction methods using short exposure bursts face challenges with strong turbulence and high computational costs. We introduce a deep learning approach that reconstructs 100 short exposure images into one high quality image in real time. Using unpaired image to image translation, our model is trained on degraded bursts with speckle reconstructions as references, improving robustness and generalization. Our method shows an improved robustness in terms of perceptual quality, especially when speckle reconstructions show artifacts. An evaluation with a varying number of images per burst demonstrates that our method makes efficient use of the combined image information and achieves the best reconstructions when provided with the full image burst.

astro-ph.SR↗