Simultaneous photometric and CARMENES spectroscopic monitoring of fast-rotating M dwarf GJ 3270. Discovery of a post-flare corotating feature

Abstract

Context: Active M dwarfs frequently exhibit large flares, which can pose an existential threat to the habitability of any planet in orbit in addition to making said planets more difficult to detect. M dwarfs do not lose angular momentum as easily as earlier-type stars, which maintain the high levels of stellar activity for far longer. Studying young, fast-rotating M dwarfs is key to understanding their near stellar environment and the evolution of activity Aims: We study stellar activity on the fast-rotating M dwarf GJ 3270. Methods: We analyzed dedicated high cadence, simultaneous, photometric and high-resolution spectroscopic observations obtained with CARMENES of GJ 3270 over 7.7 h, covering a total of eight flares of which two are strong enough to facilitate a detailed analysis. We consult the TESS data, obtained in the month prior to our own observations, to study rotational modulation and to compare the TESS flares to those observed in our campaign. Results: The TESS data exhibit rotational modulation with a period of 0.37 d. The strongest flare covered by our observing campaign released a total energy of about 3.6e32 erg, putting it close to the superflare regime. This flare is visible in the B,V, r, i, and z photometric bands, which allows us to determine a peak temperature of about 10,000 K. The flare also leaves clear marks in the spectral time series. In particular, we observe an evolving, mainly blue asymmetry in chromospheric lines, which we attribute to a post-flare, corotating feature. To our knowledge this is the first time such a feature has been seen on a star other than our Sun. Conclusions: Our photometric and spectroscopic time series covers the eruption of a strong flare followed up by a corotating feature analogous to a post-flare arcadal loop on the Sun with a possible failed ejection of material.

arXiv commentA&A, in press

References in corpus (61)

• Gaia Data Release 2. Summary of the contents and survey properties
• The Transiting Exoplanet Survey Satellite
• Intrinsic Colors, Temperatures, and Bolometric Corrections of Pre-Main Sequence Stars
• A new extensive library of PHOENIX stellar atmospheres and synthetic spectra
• The generalised Lomb-Scargle periodogram. A new formalism for the floating-mean and Keplerian periodograms
• The WASP Project and the SuperWASP Cameras
• The Fourth US Naval Observatory CCD Astrograph Catalog (UCAC4)
• On the rotational evolution of solar- and late-type stars, its magnetic origins, and the possibility of stellar gyrochronology
• Constraining the Age-Activity Relation for Cool Stars: The SDSS DR5 Low-Mass Star Spectroscopic Sample
• Correcting systematic effects in a large set of photometric lightcurves
• A self-consistent, absolute isochronal age scale for young moving groups in the solar neighbourhood
• New Neighbors from 2MASS: Activity and Kinematics at the Bottom of the Main Sequence
• Superflares on Solar Type Stars Observed with Kepler I. Statistical Properties of Superflares
• The Effect of a Strong Stellar Flare on the Atmospheric Chemistry of an Earth-like Planet Orbiting an M dwarf
• Stellar Flares from the First Tess Data Release: Exploring a New Sample of M-dwarfs
• Binning is sinning: morphological light-curve distortions due to finite integration time
• The rotation and Galactic kinematics of mid M dwarfs in the Solar Neighborhood
• Chromospheric Activity, Rotation, and Rotational Braking in M and L Dwarfs
• The CARMENES search for exoplanets around M dwarfs: High-resolution optical and near-infrared spectroscopy of 324 survey stars
• Modeling Repeated M-dwarf Flaring at an Earth-like Planet in the Habitable Zone: I. Atmospheric Effects for an Unmagnetized Planet
• The standard flare model in three dimensions. II. Upper limit on solar flare energy
• The CARMENES search for exoplanets around M dwarfs: Different roads to radii and masses of the target stars
• A catalogue of rotation and activity in early-M stars
• Radius Dependent Angular Momentum Evolution in Low-Mass Stars. I
• The low-level radial velocity variability in Barnard's star (=GJ 699). Secular acceleration, indications for convective redshift, and planet mass limits
• Transit Detection in the MEarth Survey of Nearby M Dwarfs: Bridging the Clean-First, Search-Later Divide
• An Activity-Rotation Relationship and Kinematic Analysis of Nearby Mid-to-Late-type M Dwarfs
• CARMENES input catalogue of M dwarfs V. Luminosities, colours, and spectral energy distributions
• Flat-relative optimal extraction. A quick and efficient algorithm for stabilised spectrographs
• CARMENES input catalogue of M dwarfs: III. Rotation and activity from high-resolution spectroscopic observations
• The quest for stellar coronal mass ejections in late-type stars: I. Investigating Balmer-line asymmetries of single stars in Virtual Observatory data
• The CARMENES search for exoplanets around M dwarfs. Activity indicators at visible and near-infrared wavelengths
• CARMENES input catalogue of M dwarfs II. High-resolution imaging with FastCam
• Magnetic fields in M dwarfs from the CARMENES survey
• M Dwarf Flares from Time-Resolved SDSS Spectra
• UV Surface Habitability of the TRAPPIST-1 System
• Multi-wavelength observations of Proxima Centauri
• Risks for life on habitable planets from superflares of their host stars
• Magnetic Inflation and Stellar Mass II: On the Radii of Single, Rapidly Rotating, Fully Convective M Dwarf Stars
• Multiwavelength observations of a giant flare on CN Leonis I. The chromosphere as seen in the optical spectra
• Extreme hydrodynamic losses of Earth-like atmospheres in the habitable zones of very active stars
• A Very Bright, Very Hot, and Very Long Flaring Event from the M Dwarf Binary System DG CVn
• Flaring activity of Proxima Centauri from TESS observations: quasi-periodic oscillations during flare decay and inferences on the habitability of Proxima b
• Time resolved spectroscopic observations of an M-dwarf flare star EV Lacertae during a flare
• MuSCAT2 multicolour validation of TESS candidates: an ultra-short-period substellar object around an M dwarf
• The largest M dwarfs flares from ASAS-SN
• Analysis and modeling of high temporal resolution spectroscopic observations of flares on AD Leo
• Double-Dipping: A New Relation between Stellar Rotation and Starspot Activity
• A census of Coronal Mass Ejections on solar-like stars
• Probing the Flare Atmospheres of M dwarfs Using Infrared Emission Lines
• Identification of a complete sample of northern ROSAT All-Sky Survey X-ray sources. VIII. The late-type stellar component
• Simultaneous Kepler/K2 and XMM-Netwon observations of superflares in the Pleiades
• Multiband photometric detection of a huge flare on the M9 dwarf 2MASSW J1707183+643933
• The dynamics of eruptive prominences
• Prominence formation and ejection in cool stars
• Magnetic field and prominences of the young, solar-like, ultra-rapid rotator V530 Per
• The CARMENES search for exoplanets around M dwarfs: Wing asymmetries of H$\alpha$, Na I D, and He I lines
• Variations in solar wind fractionation as seen by ACE/SWICS over a solar cycle and the implications for Genesis Mission results
• Slingshot prominences: coronal structure, mass loss and spin down
• Strong Blue Asymmetry in Hα line as a Preflare Activity
• The Discovery of an X-ray/UV Stellar Flare from the Late-K/Early-M Dwarf LMC 335

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