Possible detection of coronal mass ejections on late-type main-sequence stars in LAMOST medium-resolution spectra

Abstract

Context. Stellar coronal mass ejections (CMEs) are the primary driver of the exoplanetary space weather and they could affect the habitability of exoplanets. However, detections of possible stellar CME signatures are extremely rare. Aims. This work aims to detect stellar CMEs from time-domain spectra observed through the LAMOST Medium-Resolution Spectroscopic Survey (LAMOST-MRS). Our sample includes 1,379,408 LAMOST-MRS spectra of 226,194 late-type main-sequence stars (${\mathrm{T}}_{\mathrm{eff}}<6000$ K, $\log [g/(\mathrm{cm}{\mathrm{s}}^{-2})]>4.0$). Methods. We first identified stellar CME candidates by examining the asymmetries of H$\alpha$ line profiles, and then performed double Gaussian fitting for H$\alpha$ contrast profiles (differences between the CME spectra and reference spectra) of the CME candidates to analyze the temporal variation of the asymmetric components. Results. Three stellar CME candidates were detected on three M dwarfs. The H$\alpha$ and Mg I triplet lines (at 5168.94 Å, 5174.13 Å, 5185.10 Å) of candidate 1 all exhibit a blue-wing enhancement, and the corresponding Doppler shift of this enhancement shows a gradually increasing trend. The H$\alpha$ line also shows an obvious blue-wing enhancement in candidate 2. In candidate 3, the H$\alpha$ line shows an obvious red-wing enhancement, and the corresponding projected maximum velocity exceeds the surface escape velocity of the host star. The lower limit of the CME mass was estimated to be $\sim$$8\times 10^{17}$ g to $4\times 10^{18}$ g for these three candidates.

Accepted by A&A

References in corpus (28)

• The Transiting Exoplanet Survey Satellite
• Probable detection of an eruptive filament from a superflare on a solar-type star
• Indications of stellar coronal mass ejections through coronal dimmings
• The Stellar CME-flare relation: What do historic observations reveal?
• Imaging and spectroscopic observations of magnetic reconnection and chromospheric evaporation in a solar flare
• Two components of the coronal emission revealed by EUV spectroscopic observations
• A stellar flare-coronal mass ejection event revealed by X-ray plasma motions
• The quest for stellar coronal mass ejections in late-type stars: I. Investigating Balmer-line asymmetries of single stars in Virtual Observatory data
• Self-consistent Stellar Radial Velocities from LAMOST Medium-Resolution Survey (MRS) DR7
• Origins of Rolling, Twisting and Non-Radial Propagation of Eruptive Solar Events
• A search for flares and mass ejections on young late-type stars in the open cluster Blanco-1
• Stellar activity with LAMOST - II. Chromospheric activity in open clusters
• Spectral observations of Ellerman bombs and fitting with a two-cloud model
• High-resolution spectroscopy of flares and CMES on AD Leo*
• A circular polarisation survey for radio stars with the Australian SKA Pathfinder
• A Monster CME Obscuring A Demon Star Flare
• Sun-as-a-star spectroscopic observations of the line-of-sight velocity of a solar eruption on October 28, 2021
• A census of Coronal Mass Ejections on solar-like stars
• LAMOST Medium-Resolution Spectroscopic Survey (LAMOST-MRS): Scientific goals and survey plan
• Search for flares and associated CMEs on late-type main-sequence stars in optical SDSS spectra
• Modeling Mg II h, k and Triplet Lines at Solar Flare Ribbons
• Radial velocity measurements from LAMOST medium-resolution spectroscopic observations: A pointing towards the Kepler field
• Detection of Flare-associated CME Candidates on Two M-dwarfs by GWAC and Fast, Time-resolved Spectroscopic Follow-ups
• Coronal Condensation as the Source of Transition Region Supersonic Downflows above a Sunspot
• Can we detect coronal mass ejections through asymmetries of Sun-as-a-star extreme-ultraviolet spectral line profiles?
• Prominence activation, optical flare, and post-flare loops on the RS Canum Venaticorum star SZ Piscium
• On-disk solar coronal condensations facilitated by magnetic reconnection between open and closed magnetic structures
• Life Beyond the Solar System: Space Weather and Its Impact on Habitable Worlds

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• Science objectives of the Einstein Probe mission
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• Full velocities and propagation directions of coronal mass ejections inferred from simultaneous full-disk imaging and Sun-as-a-star spectroscopic observations
• Application of a magnetic-field-induced transition in Fe X to solar and stellar coronal magnetic field measurements
• A Statistical Study of Soft X-ray Flares on Solar-type Stars
• $\mathrm{H}\alpha$ chromospheric activity of F-, G-, and K-type stars observed by the LAMOST Medium-Resolution Spectroscopic Survey
• Doppler-shifted Signatures in the Chromospheric Line Profiles of II Pegasi
• Investigating Possible Stellar Coronal Mass Ejections in M-type Dwarfs Using the CARMENES DR1 Spectra
• Einstein Probe Discovery of an X-ray Flare from K-type Star PM J23221-0301
• Intensities of the hydrogen Balmer lines of solar-like stars revealed by the LAMOST spectroscopic surveys
• Locate a stellar flare from the M dwarf LAMOST J1332+5057
• A Possible Stellar CME Event Associated with a Long-duration Optical Flare on the RS CVn-type Star UX Arietis