Magnetic activity on the young Sun: a case study of EK Draconis

Abstract

Context. Young, solar analogue stars provide key insights into the early stages of stellar evolution, particularly in terms of magnetic activity and rotation. Their rapid rotation, high flaring rate, and enhanced surface activity make them ideal laboratories for testing stellar models or even the solar dynamo. Aims. Using long-term photometric data, we investigated the cyclic behaviour of EK Dra over the last century. We analyze its short-term activity based on 13 Transiting Exoplanet Survey Satellite (TESS) sectors. Applying Doppler imaging on high-resolution spectral data we investigate short and long-term spot evolution and surface differential rotation. Methods. We use Short-term Fourier-transform on a 120 years long archival photometric data in order to search for activity cycles. The short-term space photometry data is fitted with an analytic three-spot model, and we hand-select flares from it to analyze their phase and frequency distribution. Spectral synthesis is used to determine the astrophysical parameters of EK Dra. Using the iMap multi-line Doppler imaging code, we reconstruct 13 Doppler images. Differential rotation is derived by cross-correlating consecutive Doppler maps. Results. Long-term photometric data reveal a 10.7-12.1 year cycle that was persistently present for 120 years. In the more recent half of the light curve a 7.3-8.2 years-long signal is also visible. The distribution of the 142 flares in the TESS data shows no correlation with the rotational phase or with the spotted longitudes. The reconstructed Doppler images show a surface that varies from rotation to rotation, putting the lower limit of the spot lifetime between 10-15 days. Based on the cross-correlation of the Doppler maps, EK Dra has a solar-type differential rotation with a surface shear parameter of ${\alpha }_{DR}=0.030\pm 0.008$.

References in corpus (47)

• Gaia Data Release 3: Summary of the content and survey properties
• The Transiting Exoplanet Survey Satellite
• A grid of MARCS model atmospheres for late-type stars I. Methods and general properties
• The NextGen Model Atmosphere grid for $3000\le \Teff \le 10000\K$
• Evolution of the Solar Activity over Time and Effects on Planetary Atmospheres: I. High-energy Irradiances (1-1700 A)
• Stellar magnetism: empirical trends with age and rotation
• Spectroscopy Made Easy: Evolution
• CERES: A Set of Automated Routines for Echelle Spectra
• Gaia Data Release 3: Astrophysical parameters inference system (Apsis) I -- methods and content overview
• The low-level radial velocity variability in Barnard's star (=GJ 699). Secular acceleration, indications for convective redshift, and planet mass limits
• Multiple and changing cycles of active stars II. Results
• Frequent flaring in the TRAPPIST-1 system - unsuited for life?
• FITSH -- a software package for image processing
• Probable detection of an eruptive filament from a superflare on a solar-type star
• Making Sense of Sunspot Decay I: Parabolic Decay Law and Gnevyshev-Waldmeier Relation
• Magnetic cycles at different ages of stars
• Correlation between lithium abundances and ages of solar twin stars
• The Magnetic Topology of the Weak-Lined T Tauri Star V410 - A Simultaneous Temperature and Magnetic Field Inversion
• Hidden magnetic fields of young suns
• K2 Ultracool Dwarfs Survey. III. White Light Flares are Ubiquitous in M6-L0 Dwarfs
• Lifetimes and Emergence/Decay Rates of Star Spots on Solar-type Stars Estimated by Kepler Data in Comparison with Those of Sunspots
• Multiple and changing cycles of active stars I. Methods of analysis and application to the solar cycles
• Flaring activity of Proxima Centauri from TESS observations: quasi-periodic oscillations during flare decay and inferences on the habitability of Proxima b
• Magnetic flux transport on active cool stars and starspot lifetimes
• Magnetic fields on young, moderately rotating Sun-like stars II. EK Draconis (HD 129333)
• Forward modelling of brightness variations in Sun-like stars I. Emergence and surface transport of magnetic flux
• Improved Photometry for the DASCH Pipeline
• 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 fast method for Stokes profile synthesis -- Radiative transfer modeling for ZDI and Stokes profile inversion
• Antisolar differential rotation of the K1-giant sigma Geminorum revisited
• The young, active binary star EK Draconis
• Rotation--differential rotation relationships for late-type single and binary stars from Doppler imaging
• Superflares on the late-type giant KIC 2852961 -- Scaling effect behind flaring at different energy levels
• Measuring differential rotation of the K-giant $\zeta$\,And
• Frequencies of flare occurrence: Interaction Between convection and coronal loops
• Observing and modelling the young solar analogue EK Draconis: starspot distribution, elemental abundances, and evolutionary status
• Stellar flare morphology with TESS across the main sequence
• Characteristics of flares on giant stars
• Magnitude-range brightness variations of overactive K giants
• A confined dynamo: magnetic activity of the K-dwarf component in the pre-cataclysmic binary system V471 Tauri
• On the Decay of Sunspot Groups and Their Internal Parts in Detail
• Zeeman Doppler Imaging of ksi Boo A and B
• EI Eridani: a star under the influence -- The effect of magnetic activity in the short and long term
• Spot evolution on LQ Hya during 2006--2017: temperature maps based on SOFIN and FIES data
• Low-latitude magnetic flux emergence on rapidly rotating solar-type stars
• Time series analysis of long-term photometry of BM Canum Venaticorum
• Four decades of photometry of XX Trianguli, `the most spotted star' in the sky