Extreme energetic particle events by superflare-associated CMEs from solar-like stars

Hu, Junxiang; Airapetian, Vladimir; Li, Gang; Zank, G. P.; Jin, Meng

doi:10.1126/sciadv.abi9743

Cited by 33 publications

(32 citation statements)

References 65 publications

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“…Such large flares are expected to be accompanied by fast and energetic coronal mass ejections propagating at a few thousands of km s −1 (Alvarado-Gómez et al 2022). Such fast CMEs are expected to initiate strong shocks and drive high fluence hard spectra stellar energetic particles, mostly protons, penetrating the equatorial regions of the disk at over 100 AU from the star, and igniting significant ionization with efficient production of H 13 CO + and N 2 H + ions on a time scale of a few weeks (Rab et al 2017(Rab et al , 2020Hu et al 2022).…”

Section: Discussion: Interior Dynamos and Surface Activitymentioning

confidence: 99%

Evolution of X-ray Activity in <25 Myr Old Pre-Main Sequence Stars

Getman,

Feigelson,

Garmire

et al. 2022

Preprint

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Measuring the evolution of X-ray emission from pre-main sequence (PMS) stars gives insight into two issues: the response of magnetic dynamo processes to changes in interior structure and the effects of high-energy radiation on protoplanetary disks and primordial planetary atmospheres. We present a sample of 6,003 stars with ages [7 − 25] Myr in ten nearby open clusters from Chandra X-ray and Gaia-EDR3 surveys. Combined with previous results in large samples of younger ( 5 Myr) stars in MYStIX and SFiNCs star forming regions, mass-stratified activity-age relations are derived for early phases of stellar evolution. X-ray luminosity (L X ) is constant during the first few Myr, possibly due to the presence of extended X-ray coronas insensitive to temporal changes in stellar size. L X then decays during the [7-25] Myr period, more rapidly as stellar mass increases. This decay is interpreted as decreasing efficiency of the α 2 dynamo as radiative cores grow and a solar-type αΩ dynamo emerges. For more massive [2 − 7] M fully radiative stars, the X-ray emission plummets indicating lack of an effective magnetic dynamos. The findings provide improved measurements of high energy radiation effects on circumstellar material, first the protoplanetary disk and then the atmospheres of young planets. The observed X-ray luminosities can be so high that an inner Earth-mass rocky, unmagnetized planet around a solar-mass PMS star might lose its primary and secondary atmospheres within a fewseveral million years. PMS X-ray emission may thus have a significant impact on evolution of early planetary atmospheres and the conditions promoting the rise of habitability.

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Section: Discussion: Interior Dynamos and Surface Activitymentioning

confidence: 99%

Evolution of X-ray Activity in <25 Myr Old Pre-Main Sequence Stars

Getman,

Feigelson,

Garmire

et al. 2022

Preprint

Self Cite

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“…The increasingly active nature of late type stars with decreasing mass has been recognized as one of the leading questions in establishing habitability of exoplanets around M-dwarfs (e.g. Hu et al 2022), and Galactic cosmic rays might similarly affect habitability in the close vicinity of a strong cosmic ray sources (e.g. Airapetian et al 2018;Thomas & Ratterman 2020).…”

Section: Cosmic Ray Acceleration By Agn Wind-driven Shocksmentioning

confidence: 99%

On the relative importance of AGN winds for the evolution of exoplanet atmospheres

Heinz

2022

Preprint

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Recent work investigating the impact of winds and outflows from active galactic nuclei (AGN) on the habitability of exoplanets suggests that such activity could be deleterious for the long-term survival of planetary atmospheres and the habitability of planets subject to such winds. Here, we discuss the relative importance of the effect of AGN winds compared to stellar winds and the effect of the planet's magnetosphere and stellar irradiation and conclude that AGN winds are not likely to play a significant role in the evolution of atmospheric conditions in planets under conditions otherwise favorable for habitability.

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“…Existing numerical analyses of the propagation of EPs from young stars surrounded by proto-planetary disks (Rodgers-Lee et al 2017;Rab et al 2017;Fraschetti et al 2018;Padovani et al 2018;Gaches & Offner 2018) or in exoplanetary environments (Fraschetti et al 2019) have focused on quiescent stellar conditions. Particle transport is determined by integrating EP trajectories in synthetic 3-dimensional turbulence (Fraschetti et al 2019) or by solving a suitable transport equation, as done recently in Hu et al (2022). However, as mentioned above, EP propagation into a realistic astrosphere disrupted by a recent (within 1 − 2 hours) CME passage does not appear to have been discussed previously.…”

Section: Introductionmentioning

confidence: 99%

Stellar Energetic Particle Transport in the Turbulent and CME-disrupted Stellar Wind of AU~Microscopii

Fraschetti¹,

Alvarado‐Gómez²,

Drake³

et al. 2022

Preprint

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Energetic particles emitted by active stars are likely to propagate in astrospheric magnetized plasma turbulent and disrupted by the prior passage of energetic Coronal Mass Ejections (CMEs). We carried out test-particle simulations of ∼ GeV protons produced at a variety of distances from the M1Ve star AU Microscopii by coronal flares or travelling shocks. Particles are propagated within the largescale quiescent three-dimensional magnetic field and stellar wind reconstructed from measured magnetograms, and within the same stellar environment following passage of a 10 36 erg kinetic energy CME. In both cases, magnetic fluctuations with an isotropic power spectrum are overlayed onto the large scale stellar magnetic field and particle propagation out to the two innnermost confirmed planets is examined. In the quiescent case, the magnetic field concentrates the particles onto two regions near the ecliptic plane. After the passage of the CME, the closed field lines remain inflated and the re-shuffled magnetic field remains highly compressed, shrinking the scattering mean free path of the particles. In the direction of propagation of the CME-lobes the subsequent EP flux is suppressed. Even for a CME front propagating out of the ecliptic plane, the EP flux along the planetary orbits highly fluctuates and peaks at ∼ 2 − 3 orders of magnitude higher than the average solar value at Earth, both in the quiescent and the post-CME cases.

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Extreme energetic particle events by superflare-associated CMEs from solar-like stars

Cited by 33 publications

References 65 publications

Evolution of X-ray Activity in <25 Myr Old Pre-Main Sequence Stars

Evolution of X-ray Activity in <25 Myr Old Pre-Main Sequence Stars

On the relative importance of AGN winds for the evolution of exoplanet atmospheres

Stellar Energetic Particle Transport in the Turbulent and CME-disrupted Stellar Wind of AU~Microscopii

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