arXiv subjects

A. Strugarek

Publications and source records attributed to A. Strugarek.

At least 19 recordsLinked to original sources

arXiv2026

Magnetic activity in cool stars: manifestations and relevance to exoplanets

Understanding stellar magnetic activity is central to exoplanet science in two ways: it sets the dynamic astrospheric boundary condition governing planetary space environments, and it is the primary obstacle to exoplanet detection and characterisation, since magnetically driven variability imprints correlated quasi-periodic signals across detection time series. In cool stars, MHD-dynamo-generated fields emerge at the photosphere as bipolar regions, drive chromospheric and coronal heating, modulate irradiance and wind, and power flares and coronal mass ejections. Spatial scales range from individual flux tubes to global coronal configurations, and temporal scales from minutes to decades and beyond, requiring observational and theoretical tools of correspondingly wide scope. We review observational manifestations and physical models of magnetic activity in stars with outer convective envelopes, addressed to the exoplanet community. We develop the solar-stellar connection through the 'Sun in Time' framework and a sequence of solar analogues serving as evolutionary snapshots of a solar-mass star over several Gyr. We survey photospheric, chromospheric, and coronal activity diagnostics across timescales, together with forward-modelling tools translating surface field distributions into signals at or above the level of exoplanet detection. Empirical rotation-activity relationships and their physical interpretation are examined across all three atmospheric layers. Surface reconstruction techniques are assessed for their diagnostic reach and limitations. The evolution of magnetism in solar-like stars is discussed as context for habitability and as a window to other worlds. We close with an account of how stellar magnetism sculpts the astrospheric environment and affects close-in exoplanets, followed by a synthesis of outstanding issues and an outlook on future prospects.

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arXiv2026

Radio emission from star-planet interactions

Stars interact with their exoplanets though gravity, radiation, plasma and magnetic fields. Stellar plasma and magnetic fields impose electrodynamic effects on exoplanet atmospheres and interiors that include heating, aurorae and atmospheric mass loss. The planets in turn can excite Alfvénic disturbances that are dissipated on the star leading to chromospheric heating and flares. This interaction, broadly called magnetic star-planet interaction (M-SPI), can also generate radio signatures both from the star and the exoplanet. The radio emission encodes information on the dynamics/energetics of the interaction, the magnetic field strength and topology of the emitter and the orbital/rotational geometry of the system -- information that is difficult or in some cases implausible to obtain by other means. Yet we do not have a conclusive detection of M-SPI in the radio band primarily due to sensitivity limitations and scarce observing time spent monitoring promising targets. Here we describe the scientific motivation to study M-SPI in exoplanetary systems, to get progress in understanding its predicted signal strength and phenomenology. We argue that the SKA telescopes can make a transformative contribution to exoplanet science by detecting M-SPI in the radio band but this will require substantial observing time -- similar to that afforded to successful optical-band searches for M-SPI signatures.

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arXiv2026

White paper on the relevance of the European Solar Telescope (EST) for the French heliophysics

The project of the European Solar Telescope aims to provide a state-of-the art infrastructure to study the Sun and its interactions with Earth and the heliosphere. This 4.2m aperture telescope will be equipped with multi conjugate adaptive optics, light-polarisation analyser, imaging spectrograph and integral field unit spectrographs. It will provide unprecedented observations of the solar photosphere and chromosphere and of the dynamical events and features that pertains to the low solar atmosphere. The EST project is presently in a phase of crystallisation, aiming at the creation of an European Research Infrastructure Consortium. While the French community has continuously been associated with the development of the EST project, some specific scientific aspects are more particularly relevant for the French astrophysics and heliophysics communities. The present review highlights the scientific research axes of high interest from the French community that shall strongly benefit from EST. The later will not only advance numerous topics of solar physics, as well as solar adaptive optics developments, but will also provide unrivaled datasets of high interest in the framework of space weather. This review also aims to highlight the space weather use that can be done with future EST observations, that will be particularly relevant for French heliophysicists.

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arXiv2026

Sungrazer comets as analogs of star-planet magnetic interactions

Star-planet magnetic interactions (SPMIs) can transfer energy from an exoplanet to its host star via Alfvén waves when the planet orbits within a sub-Alfvénic stellar wind. Similar conditions were encountered by the sungrazing comet Lovejoy as it passed through the solar corona in December 2011. The possibility that comets could trigger solar activity via magnetic interactions has never been investigated. The aim of this paper is to quantify the energetics of such interaction and to assess if enough energy could be deposited to either form a hotspot or trigger eruptions on the Sun. We used the magnetohydrodynamic WindPredict-AW model to reconstruct the coronal magnetic field and solar wind conditions along the comet's orbit, and determined the magnetic footpoints that connected the comet to the solar surface. By estimating the travel time of hypothetical Alfvén waves, we identified a brightening event observed by EUVI aboard STEREO-A that is spatially and temporally consistent with comet Lovejoy's passage. We then computed the SPMI power for all magnetic field lines anchored within 5 degrees of the brightening using SPMI power scaling laws. The resulting power distribution spans approximately 10$^{14}$-10$^{16}$ W. In comparison, the estimated radiative power of the brightening event in the STEREO-A/EUVI 195$Å$ channel is approximately 10$^{17}$ W. We find that comet Lovejoy does not generate sufficient SPMI power to be the energy source of the observed brightening intensity. However, it may still act as a perturbation to existing magnetic structures, and lead to the triggering of solar flares. Confirming this hypothesis would require additional observations that do not exist for this event, which make future passages of sungrazing comets valuable opportunities to study SPMI processes within our solar system.

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arXiv2026

Energetics and Emission in a Simulated Solar Flare Initialised by a Non-Force Free Magnetic Field

Solar flare simulations are commonly initialised using non-linear force free field (NLFF) extrapolations derived from photospheric vector magnetograms. However, the force free assumption neglects plasma forces and may limit the available free magnetic energy. In this work, we perform a controlled comparison of two three-dimensional resistive magnetohydrodynamic simulations of the X2.1-class flare that occurred on 2011 September 06 in NOAA Active Region 11283. The simulations differ only in their initial magnetic configuration: one is based on a conventional NLFF extrapolation, while the other employs a non-force free extrapolation. Both models are evolved in an identical stratified atmosphere using the same numerical framework, enabling direct assessment of how the initial magnetic assumptions influence flare dynamics and energetics. We find that the non-force free model undergoes more extensive magnetic restructuring and releases approximately twice as much magnetic energy ($\approx4.4 \times 10^{31}$ erg) as the NLFF case ($\approx2.3 \times 10^{31}$ erg), bringing the energy budget into closer agreement with expectations for X-class flares. Synthetic extreme ultraviolet emission in the 94A channel is computed for both simulations and compared with observations from the Solar Dynamics Observatory. The non-force free model produces a brighter and more spatially extended emission structure that more closely resembles the observed flare morphology and light curve. These results demonstrate that assumptions made in constructing the pre-flare coronal magnetic field can significantly affect flare energetics and observable signatures, and suggest that non-force free extrapolations provide a promising pathway toward more realistic data-constrained flare modelling.

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arXiv2026

Formation and rising phase of a flux rope through data-constrained simulations

Context. Data-constrained models incorporate observed photospheric magnetic fields. However, due to the lack of magnetic field information in the rest of the solar atmosphere, models rely on extrapolations that, in most cases, neglect the Lorentz force. Nevertheless, this force is present in the lower atmosphere and may play a key role in destabilising the equilibrium configuration and triggering eruptions. Aims. This study seeks to understand and reproduce a solar eruption SOL2014-12-18T21:41 that occurred in active region NOAA 12241, preceded by an M6.9 flare, and to investigate the impact of relaxing the initial force-free assumption. Methods. The resistive and compressible magnetohydrodynamic simulation is initiated using a non-force-free magnetic field extrapolated from a photospheric vector magnetogram taken minutes before the flare. The simulation includes a stratified atmosphere and non-ideal effects such as thermal conduction and radiative cooling. Results. A flux rope forms and rises in the simulation, carrying away dense material from the lower solar atmosphere. Its formation results from the non-zero Lorentz force acting on the initial sheared arcade, without assuming pre-existing flux ropes or photospheric driving motions. The flux rope is then deflected toward regions of low magnetic pressure, escaping the domain at 350 km/s with approximately constant acceleration. Conclusions. A robust numerical framework for modelling flaring active regions was applied to the eruption of NOAA AR12241 as a case study, assuming a realistic non-force-free magnetic field near the flare onset. It exemplifies how an initial Lorentz force imbalance can successfully trigger a flux rope formation that later escapes the simulation domain. It also enables comparison with real observations through the addition of a stratified atmosphere spanning from the photosphere to the corona.

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arXiv2025

A predictive framework for realistic star planet radio emission in compact systems

Radio emission from star planet interactions (SPI) beyond our solar system has yet to be firmly detected, primarily due to challenges such as weak signals, directional beaming effects, and low frequency emissions that are blocked by the ionosphere of Earth. Addressing these obstacles calls for strategic target selection. This proof of concept study aims to improve SPI target prioritization by simulating SPI induced radio emission frequencies and estimating associated radio power to identify systems most likely to produce detectable signals. We combine Zeeman Doppler Imaging (ZDI) maps with 3D magnetohydrodynamic (MHD) stellar wind simulations and use the ExPRES code to model SPI driven radio emissions. We also estimate the intensity of these emissions using the Radio Magnetic Scaling Law, based on the magnetic field and plasma density parameters from the 3D wind models. This approach is applied to systems such as Tau Boo, HD 179949, and HD 189733 to assess their detectability with current and future radio telescopes. This framework, tested on benchmark systems, is applicable to any star planet system with available ZDI maps and wind models. As magnetic field reconstructions and wind simulations improve, the method will become more robust. It provides a data driven approach to prioritize targets and optimize telescope scheduling. This shall enable systematic exploration of magnetic SPI radio emissions across a wide range of exoplanetary systems.

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arXiv2025

Detecting and characterising the magnetic field of exoplanets

Magnetic fields play a crucial role in planetary evolution and habitability. While the intrinsic magnetic fields of solar system planets are relatively well understood, the magnetic properties of exoplanets remain largely unconstrained, despite their potential ubiquity. Detecting exoplanetary magnetic fields is essential to advancing our understanding of planetary habitability beyond the solar system. This paper focuses on two promising spectropolarimetric techniques for detecting magnetic fields in hot exoplanets: direct detection through polarization signatures in the He I 1083 nm triplet and indirect detection via star-planet magnetic interactions manifesting as stellar hot spots. The direct method is particularly suited to close-in gas giants, leveraging the Hanle and Zeeman effects to detect low-amplitude magnetic fields. The indirect method can apply to both giant and low-mass planets by identifying magnetic connectivity-induced features in the stellar atmosphere. Although the interpretation of current detections remain tentative, upcoming high-resolution spectropolarimetric capabilities in the UV and near-infrared, particularly with future missions like HWO, promise to enable definitive measurements of exoplanetary magnetic fields. These advancements will open new avenues for probing the magnetic environments of exoplanets and their implications for atmospheric retention and habitability.

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arXiv2025

Non-transiting exoplanets as a means of understanding star-planet interactions in close-in systems

Previous studies showed evidence of a dearth of close-in exoplanets around fast rotators, which can be explained by the combined action of intense tidal and magnetic interactions between planets and their host star. Detecting more exoplanets experiencing such interactions, with orbits evolving on short timescales, is therefore crucial to improve our understanding of the underlying physical mechanisms. For this purpose, we performed a new search for close-in non-transiting substellar companions in the Kepler data, focusing on orbital periods below 2.3 days. We focused on main-sequence solar-type stars and subgiant stars for which a surface rotation period was measured. For each star, we looked for an excess in the power spectral density of the light curve, which could correspond to the signature of a close-in non-transiting companion. We compared our candidates with existing catalogues to eliminate potential contaminants in our sample, and we visually inspected the phase-folded light curve and its wavelet decomposition. We identify 88 stars exhibiting a signature consistent with the presence of a close non-transiting substellar companion. We show that the objects in our sample are located mostly within the dearth zone, emphasising the importance of performing follow-up of such systems in order to gather observational evidence of star-planet interactions.

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arXiv2025

A circularly polarized low-frequency radio burst from the exoplanetary system HD 189733

We aim to detect low-frequency radio emission from exoplanetary systems, which can provide insights into planetary magnetic fields, star-planet interactions, stellar activity, and exo-space weather. The HD 189733 system, hosting a well-studied hot Jupiter, is a prime target for such searches. We conducted NenuFAR imaging observations in the 15-62 MHz range, in order to cover the entire orbital phase of HD 189733 b. Dynamic spectra were generated for the target and other sources in the field, followed by a transient search in the time-frequency plane. The data processing pipeline incorporated direction-dependent calibration and noise characterization to improve sensitivity. We also searched for periodic signals using Lomb-Scargle analysis. A highly circularly polarized radio burst was detected at 50 MHz with a flux density of 1.5 Jy and a significance of 6 sigma at the position of HD 189733. No counterpart was found in Stokes I, likely because the emission is embedded in confusion noise and remains below the detection threshold. The estimated minimum fractional circular polarization of 38% suggests a coherent emission process. A periodicity search revealed no weaker signals linked to the planet's orbital period, the star's rotational period, or the synodic period and harmonic period between them. The burst's properties are consistent with cyclotron maser instability (CMI) emission, but the origin is still ambiguous. The comparison with theoretical models suggests star-planet interaction or stellar activity as potential origins. However, alternative explanations such as contamination from other sources along the line of sight (e.g. the companion M dwarf) or noise fluctuation cannot be ruled out.

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arXiv2025

Forecasting the solar cycle using variational data assimilation: validation on cycles 22 to 25

Forecasting future solar activity has become crucial in our modern world, where intense eruptive phenomena mostly occurring during solar maximum are likely to be strongly damaging to satellites and telecommunications. We present a 4D variational assimilation technique applied for the first time to real solar data. Our method is tested against observations of past cycles 22, 23, 24 and on the ongoing cycle 25 for which we give an estimate of the imminent maximum value and timing and also provide a first forecast of the next solar minimum. We use a variational data assimilation technique applied to a solar mean-field Babcock-Leighton flux-transport dynamo model. Ensemble predictions are produced in order to obtain uncertainties on the timing and value of the maximum of cycle $n+1$, when data on cycle $n$ is assimilated. We study in particular the influence of the phase during which data is assimilated in the model and of the weighting of various terms in the objective function. The method is validated on cycles 22, 23 and 24 with very satisfactory results. For cycle 25, predictions vary depending on the extent of the assimilation window but start converging past 2022 to a solar maximum reached between mid-2024 up to the beginning of 2025 with a sunspot number value of $143.1 \pm 15.0$. Relatively close values of the maximum are found in both hemispheres within a time lag of a few months. We also forecast a next minimum around late 2029, with still significant errorbars. The data assimilation technique presented here combining a physics-based model and real solar observations produces promising results for future solar activity forecasting.

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arXiv2025

Introduction to magnetic star-planet interactions

The interaction between planets and their host stars is governed by the forces of gravity, radiation, and magnetic fields. For planets orbiting their stars at distances of approximately 10 stellar radii or less, these effects are significantly intensified. Such interactions can be investigated through a combination of photometric, spectroscopic, and spectropolarimetric studies spanning wavelengths from X-rays to radio frequencies. When a hot planet resides within the star's sub-Alfvénic radius, magnetic star-planet interactions (SPI) become possible, often observable as stellar activity enhancements influenced by the planet's orbital motion rather than stellar rotation alone. Such interactions offer a unique perspective on the atmospheric erosion and magnetospheric characteristics of close-in exoplanets.The behavior and impacts of these magnetic interactions are highly sensitive to the magnetic fields of both the planet and its host star. This interplay can influence the magnetic activity of both bodies and has implications for the planet's irradiation levels, orbital migration, and the star's rotational dynamics. By employing phase-resolved observational methods on an expanding sample of hot Jupiter (HJ) systems, researchers can now extend these studies to other compact star-planet systems, including smaller planets in the habitable zones of M dwarfs. Efforts to comprehend magnetic SPI have led to extensive advancements in theoretical research and computational modeling. These efforts include investigations into the space weather environments of close-in giant exoplanets. Utilizing hydrodynamical (HD) and magnetohydrodynamical (MHD) simulations, researchers aim to provide both qualitative and quantitative descriptions of SPI. In this chapter, we first review notable SPI detections before summarizing the current understanding of the underlying physical mechanisms driving SPI.

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arXiv2024

Ohmic heating in the upper atmosphere of hot exoplanets The influence of a time-varying magnetic field

Exoplanets on close-in orbit are subject to intense X-ray and ultraviolet (XUV) irradiation from their star. Their atmosphere therefore heats up, sometimes to the point where it thermally escapes from the gravitational potential of the planet. Nonetheless, XUV is not the only source of heating in such atmospheres. Indeed, close-in exoplanets are embedded in a medium (the stellar wind) with strong magnetic fields that can significantly vary along the orbit. The variations of this magnetic field can induce currents in the upper atmosphere, which dissipate and locally heat it up through Ohmic heating. The aim of this work is to quantify Ohmic heating in the upper atmosphere of hot exoplanets due to an external time-varying magnetic field, and to compare it to the XUV heating. Ohmic heating depends strongly on the conductivity properties of the upper atmosphere. A 1D formalism is developed to assess the level and the localization of Ohmic heating depending on the conductivity profile, and applied to the specific cases of Trappist-1 b and $π$ Men c. Ohmic heating can reach values up to 10$^{-3}$ erg s$^{-1}$ cm$^{-3}$ in the upper atmospheres of hot exoplanets. It is expected to be stronger the closer the planet is and the lower the central star mass is, as these conditions maximize the strength of the ambient magnetic field around the planet. We confirm that Ohmic heating can play an important role in setting the thermal budget of the upper atmosphere of hot exoplanets, and can even surpass the XUV heating in the most favorable cases. When it is strong, a corollary is that the upper atmosphere screens efficiently time-varying external magnetic fields, preventing them to penetrate deeper in the atmosphere or inside the planet itself. We find that both Trappist-1b and $π$ Men c are likely subject to intense Ohmic heating.

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arXiv2024

Measuring stellar surface rotation and activity with the PLATO mission -- I. Strategy and application to simulated light curves

The Planetary Transits and Oscillations of stars mission (PLATO) will allow us to measure surface rotation and monitor photometric activity of tens of thousands of main sequence solar-type and subgiant stars. This paper is the first of a series dedicated to the preparation of the analysis of stellar surface rotation and photospheric activity with the near-future PLATO data. We describe in this work the strategy that will be implemented in the PLATO pipeline to measure stellar surface rotation, photometric activity, and long-term modulations. The algorithms are applied on both noise-free and noisy simulations of solar-type stars, which include activity cycles, latitudinal differential rotation, and spot evolution. PLATO simulated systematics are included in the noisy light curves. We show that surface rotation periods can be recovered with confidence for most of the stars with only six months of observations and that the {recovery rate} of the analysis significantly improves as additional observations are collected. This means that the first PLATO data release will already provide a substantial set of measurements for this quantity, with a significant refinement on their quality as the instrument obtains longer light curves. Measuring the Schwabe-like magnetic activity cycle during the mission will require that the same field be observed over a significant timescale (more than four years). Nevertheless, PLATO will provide a vast and robust sample of solar-type stars with constraints on the activity-cycle length. Such a sample is lacking from previous missions dedicated to space photometry.

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arXiv2023

On Earth's habitability over the Sun's main-sequence history: joint influence of space weather and Earth's magnetic field evolution

The aim of this study is to analyze the Earth habitability with respect to the direct exposition of the Earth atmosphere to the solar wind along the Suns evolution on the main sequence including the realistic evolution of the space weather conditions and the Earth magnetic field. The MHD code PLUTO in spherical coordinates is applied to perform parametric studies with respect to the solar wind dynamic pressure and the interplanetary magnetic field intensity for different Earth magnetic field configurations. Quiet space weather conditions may not impact the Earth habitability. On the other hand, the impact of interplanetary coronal mass ejections (ICME) could lead to the erosion of the primary Earth atmosphere during the Hadean eon. A dipolar field of 30 microT is strong enough to shield the Earth from the Eo-Archean age as well as 15 and 5 microT dipolar fields from the Meso-Archean and Meso-Proterozoic, respectively. Multipolar weak field period during the Meso-Proterozoic age may not be a threat for ICME-like space weather conditions if the field intensity is at least 15 microT and the ratio between the quadrupolar (Q) and dipolar (D) coefficients is Q/D <= 0.5. By contrast, the Earth habitability in the Phanerozoic eon (including the present time) can be hampered during multipolar low field periods with a strength of 5 microT and Q/D >= 0.5 associated to geomagnetic reversals. Consequently, the effect of the solar wind should be considered as a possible driver of Earth's habitability.

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arXiv2023

Stellar spectral-type (mass) dependence of the dearth of close-in planets around fast-rotating stars. Architecture of Kepler confirmed single-exoplanet systems compared to star-planet evolution models

In 2013 a dearth of close-in planets around fast-rotating host stars was found using statistical tests on Kepler data. The addition of more Kepler and Transiting Exoplanet Survey Satellite (TESS) systems in 2022 filled this region of the diagram of stellar rotation period (Prot) versus the planet orbital period (Porb). We revisited the Prot extraction of Kepler planet-host stars, we classify the stars by their spectral type, and we studied their Prot-Porb relations. We only used confirmed exoplanet systems to minimize biases. In order to learn about the physical processes at work, we used the star-planet evolution code ESPEM (French acronym for Evolution of Planetary Systems and Magnetism) to compute a realistic population synthesis of exoplanet systems and compared them with observations. Because ESPEM works with a single planet orbiting around a single main-sequence star, we limit our study to this population of Kepler observed systems filtering out binaries, evolved stars, and multi-planets. We find in both, observations and simulations, the existence of a dearth in close-in planets orbiting around fast-rotating stars, with a dependence on the stellar spectral type (F, G, and K), which is a proxy of the mass in our sample of stars. There is a change in the edge of the dearth as a function of the spectral type (and mass). It moves towards shorter Prot as temperature (and mass) increases, making the dearth look smaller. Realistic formation hypotheses included in the model and the proper treatment of tidal and magnetic migration are enough to qualitatively explain the dearth of hot planets around fast-rotating stars and the uncovered trend with spectral type.

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arXiv2023

Investigating the visible phase-curve variability of 55 Cnc e

55 Cnc e is an ultra-short period super-Earth transiting a Sun-like star. Previous observations in the optical range detected a time-variable flux modulation that is phased with the planetary orbital period, whose amplitude is too large to be explained by reflected light and thermal emission alone. The goal of the study is to investigate the origin of the variability and timescale of the phase-curve modulation in 55 Cnc e. To this end, we used the CHaracterising ExOPlanet Satellite (CHEOPS), whose exquisite photometric precision provides an opportunity to characterise minute changes in the phase curve from one orbit to the next. CHEOPS observed 29 individual visits of 55 Cnc e between March 2020 and February 2022. Based on these observations, we investigated the different processes that could be at the origin of the observed modulation. In particular, we built a toy model to assess whether a circumstellar torus of dust driven by radiation pressure and gravity might match the observed flux variability timescale. We find that the phase-curve amplitude and peak offset of 55 Cnc e do vary between visits. The sublimation timescales of selected dust species reveal that silicates expected in an Earth-like mantle would not survive long enough to explain the observed phase-curve modulation. We find that silicon carbide, quartz, and graphite are plausible candidates for the circumstellar torus composition because their sublimation timescales are long. The extensive CHEOPS observations confirm that the phase-curve amplitude and offset vary in time.We find that dust could provide the grey opacity source required to match the observations. However, the data at hand do not provide evidence that circumstellar material with a variable grain mass per unit area causes the observed variability. Future observations with the James Webb Space Telescope promise exciting insights into this iconic super-Earth.

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arXiv2023

MHD study of extreme space weather conditions for exoplanets with Earth-like magnetospheres: On habitability conditions and radio-emission

The present study aims at characterizing the habitability conditions of exoplanets with an Earth-like magnetosphere inside the habitable zone of M stars and F stars like tau Boo, caused by the direct deposition of the stellar wind on the exoplanet surface if the magnetosphere shielding is inefficient. In addition, the radio emission generated by exoplanets with a Earth-like magnetosphere is calculated for different space weather conditions. The study is based on a set of MHD simulations performed by the code PLUTO reproducing the space weather conditions expected for exoplanets orbiting the habitable zone of M stars and F stars type tau Boo. Exoplanets hosted by M stars at 0.2 au are protected from the stellar wind during regular and CME-like space weather conditions if the star rotation period is slower than 3 days, that is to say, faster rotators generate stellar winds and interplanetary magnetic fields large enough to endanger the exoplanet habitability. Exoplanets hosted by a F stars type tau Boo at >= 2.5 au are protected during regular space weather conditions, but a stronger magnetic field compared to the Earth is mandatory if the exoplanet is close to the inner edge of the star habitable zone (2.5 au) to shield the exoplanet surface during CME-like space weather conditions. The range of radio emission values calculated in the simulations are consistent with the scaling proposed by [Zarka 2018] during regular and common CME-like space weather conditions. If the radio telescopes measure a relative low radio emission signal with small variability from an exoplanet, that may indicate favorable exoplanet habitability conditions with respect to the space weather states considered and the intrinsic magnetic field of the exoplanet.

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