Optical and X-ray observations of stellar flares on an active M dwarf AD Leonis with Seimei Telescope, SCAT, NICER and OISTER

Abstract

We report multi-wavelength monitoring observations of an M-dwarf flare star AD Leonis with Seimei Telescope (6150--7930 Å), SCAT (Spectroscopic Chuo-university Astronomical Telescope; 3700--7500 Å), NICER (Neutron Star Interior Composition Explorer; 0.2--12.0 keV), and collaborations of OISTER (Optical and Infrared Synergetic Telescopes for Education and Research) program. Twelve flares are detected in total which include ten H$\alpha$, four X-ray, and four optical-continuum flares; one of them is a superflare with the total energy of $\sim$ 2.0$\times$10${}^{33}$ erg. We found that (1) during the superflare, the H$\alpha$ emission line full width at 1/8 maximum dramatically increases to 14 Å from 8 Å in the low-resolution spectra (R$\sim$ 2000) accompanied with the large white-light flares, (2) some weak H$\alpha$/X-ray flares are not accompanied with white-light emissions, and (3) the non-flaring emissions show clear rotational modulations in X-ray and H$\alpha$ intensity in the same phase. To understand these observational features, one-dimensional hydrodynamic flare simulations are performed by using the RADYN code. As a result of simulations, we found the simulated H$\alpha$ line profiles with hard and high-energy non-thermal electron beams are consistent with that of the initial phase line profiles of the superflares, while those with more soft- and/or weak-energy beam are consistent with those in decay phases, indicating the changes in the energy fluxes injected to the lower atmosphere. Also, we found that the relation between optical continuum and H$\alpha$ intensity is nonlinear, which can be one cause of the non-white-light flares. The flare energy budget exhibits diversity in the observations and models, and more observations of stellar flares are necessary for constraining the occurrence of various emission line phenomena in stellar flares.

18 pages, 17 figures, Accepted for Publication in PASJ

References in corpus (18)

• The Transiting Exoplanet Survey Satellite
• Kepler Flares I. Active and Inactive M dwarfs
• Kepler Flares II: The Temporal Morphology of White-Light Flares on GJ 1243
• Do Kepler superflare stars really include slowly-rotating Sun-like stars ? - Results using APO 3.5m telescope spectroscopic observations and Gaia-DR2 data -
• Radiative Hydrodynamic Models of Optical and Ultraviolet Emission from M Dwarf Flares
• Optical, UV, and X-Ray Evidence for a 7-Year Stellar Cycle in Proxima Centauri
• The quest for stellar coronal mass ejections in late-type stars: I. Investigating Balmer-line asymmetries of single stars in Virtual Observatory data
• New Insights into White-Light Flare Emission from Radiative-Hydrodynamic Modeling of a Chromospheric Condensation
• Risks for life on habitable planets from superflares of their host stars
• Hydrogen Balmer Line Broadening in Solar and Stellar Flares
• The coronal structure of AB Dor determined from contemporaneous Doppler imaging and X-ray spectroscopy
• Long-Lasting Extreme Magnetic Storm Activities in 1770 Found in Historical Documents
• High-resolution spectroscopy of flares and CMES on AD Leo*
• Large X-ray Flares on Stars Detected with MAXI/GSC: A Universal Correlation between the Duration of a Flare and its X-ray Luminosity
• Analysis and modeling of high temporal resolution spectroscopic observations of flares on AD Leo
• Spectral Evidence for Heating at Large Column Mass in Umbral Solar Flare Kernels I: IRIS NUV Spectra of the X1 Solar Flare of 2014 Oct 25
• Characteristics that Produce White-Light Enhancements in Solar Flares Observed by Hinode/SOT
• Testing the solar activity paradigm in the context of exoplanet transits

Cited by in corpus (41)

• Probable detection of an eruptive filament from a superflare on a solar-type star
• Statistical Properties of Superflares on Solar-type Stars: Results Using All of the Kepler Primary Mission Data
• Sun-as-a-star Analyses of Various Solar Active Events Using H$\alpha$ Spectral Images Taken by SMART/SDDI
• Detection of Flare-induced Plasma Flows in the Corona of EV Lac with X-ray Spectroscopy
• Giant white-light flares on fully convective stars occur at high latitudes
• APO & SMARTS flare star campaign observations I. Blue wing asymmetries in chromospheric lines during mid M dwarf flares from simultaneous spectroscopic and photometric observation data
• Detection of a high-velocity prominence eruption leading to a CME associated with a superflare on the RS CVn-type star V1355 Orionis
• Discovery of a Long-Duration Superflare on a Young Solar-Type Star EK Draconis with Nearly Similar Time Evolution for H$\alpha$ and White-Light Emissions
• A Seven-Day Multi-Wavelength Flare Campaign on AU Mic I: High-Time Resolution Light Curves and the Thermal Empirical Neupert Effect
• Starspot mapping with adaptive parallel tempering. II. Application to TESS data for M-dwarf flare stars, AU Microscopii, YZ Canis Minoris, and EV Lacertae
• The Atmospheric Response to High Nonthermal Electron Beam Fluxes in Solar Flares. II. Hydrogen Broadening Predictions for Solar Flare Observations with the Daniel K. Inouye Solar Telescope
• The CARMENES search for exoplanets around M dwarfs: Stable radial-velocity variations at the rotation period of AD~Leonis -- A test case study of current limitations to treating stellar activity
• Monitoring the large-scale magnetic field of AD~Leo with SPIRou, ESPaDOnS and Narval. Toward a magnetic polarity reversal?
• Sun-as-a-star Analysis of H$\alpha$ Spectra of a Solar Flare Observed by SMART/SDDI: Time Evolution of Red Asymmetry and Line Broadening
• Fast optical flares from M dwarfs detected by a one-second-cadence survey with Tomo-e Gozen
• The Great Flare of 2021 November 19 on AD Leo. Simultaneous XMM-Newton and TESS observations
• A Superflare on YZ Canis Minoris Observed by Seimei Telescope and TESS: Red Asymmetry of H$\alpha$ Emission Associated with White-Light Emission
• Energetic particle activity in AD Leo: Detection of a solar-like type-IV burst
• Data-driven MHD simulation of successive solar plasma eruptions
• Reconstructing the XUV Spectra of Active Sun-like Stars Using Solar Scaling Relations with Magnetic Flux
• M-dwarf's Chromosphere, Corona and Wind Connection via the Nonlinear Alfvén Wave
• Bridging High-Density, Electron Beam Coronal Transport and Deep Chromospheric Heating in Stellar Flares
• The Mouse that Squeaked: A small flare from Proxima Cen observed in the millimeter, optical, and soft X-ray with Chandra and ALMA
• Red Asymmetry of H${}_{\alpha }$ Line Profiles during the flares on the active RS CVn-type star II Pegasi
• X-ray/H$\alpha$ scaling relationships in stellar flares
• Lower-than-expected flare temperatures for TRAPPIST-1
• Flaring-associated Complex Dynamics in Two M-dwarfs Revealed by Fast, Time-resolved Spectroscopy
• Location and energy of electrons producing the radio bursts from AD Leo observed by FAST in December 2021
• Blackbody temperature of 200+ stellar flares observed with the CoRoT satellite
• Do Young Suns Produce Frequent, Massive CMEs? Results from Five-year Dedicated Optical Observations of EK Draconis and V889 Hercules
• Simultaneous X-ray and optical variability of M dwarfs observed with eROSITA and TESS
• A Seven-Day Multi-Wavelength Flare Campaign on AU Mic III: Quiescent and Flaring Properties of the X-ray Spectra and Chromospheric lines
• Under the magnifying glass: A combined 3D model applied to cloudy warm Saturn type exoplanets around M-dwarfs
• Starspots as the origin of ultrafast drifting radio bursts from an active M dwarf
• The Puzzling Story of Flare Inactive Ultra Fast Rotating M dwarfs. II. Searching for radial velocity variations
• The Flare-Activity of 2MASSJ16111534-1757214 in the Upper Scorpius association
• Doppler-shifted Signatures in the Chromospheric Line Profiles of II Pegasi
• X-ray and Hα superflare on an RS CVn-type star, UX Arietis: Constraint on the flare location from radial velocity change during the flare
• 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
• Role of non-thermal processes in the quiescent and active millimeter spectrum of a young M dwarf