Far beyond the Sun: II. Probing the stellar magnetism of the young Sun ι Horologii from the photosphere to its corona

Abstract

A comprehensive multi-wavelength campaign has been carried out to probe stellar activity and variability in the young Sun-like star $\iota$-Horologii. We present the results from long-term spectropolarimetric monitoring of the system by using the ultra-stable spectropolarimeter/velocimeter HARPS at the ESO 3.6-m telescope. Additionally, we included high-precision photometry from the NASA Transiting Exoplanet Survey Satellite (TESS) and observations in the far- and near-ultraviolet spectral regions using the STIS instrument on the NASA/ESA Hubble Space Telescope (HST). The high-quality dataset allows a robust characterisation of the star's rotation period, as well as a probe of the variability using a range of spectroscopic and photometric activity proxies. By analyzing the gradient of the power spectra (GPS) of the TESS lightcurves we constrained the faculae-to-spot driver ratio (${\mathrm{S}}_{\mathrm{fac}}/{\mathrm{S}}_{\mathrm{spot}}$) to 0.510$\pm$0.023, which indicates that the stellar surface is spot dominated during the time of the observations. We compared the photospheric activity properties derived from the GPS method with a magnetic field map of the star derived using Zeeman-Doppler imaging (ZDI) from simultaneous spectropolarimetric data for the first time. Different stellar activity proxies enable a more complete interpretation of the observed variability. For example, we observed enhanced emission in the HST transition line diagnostics C IV and C III, suggesting a flaring event. From the analysis of TESS data acquired simultaneously with the HST data, we investigate the photometric variability at the precise moment that the emission increased and derive correlations between different observables, probing the star from its photosphere to its corona.

References in corpus (35)

• The Transiting Exoplanet Survey Satellite
• The generalised Lomb-Scargle periodogram. A new formalism for the floating-mean and Keplerian periodograms
• Measuring the rotation period distribution of field M-dwarfs with Kepler
• The Structure of the Local Interstellar Medium V: Electron Densities
• Generalized investigation of the rotation-activity relation: Favouring rotation period instead of Rossby number
• Solar-type dynamo behaviour in fully convective stars without a tachocline
• Magnetic cycles of the planet-hosting star tauBootis
• The Extrasolar Planet epsilon Eridani b - Orbit and Mass
• Magnetism, rotation, and nonthermal emission in cool stars -- Average magnetic field measurements in 292 M dwarfs
• New Observational Constraints on the Winds of M Dwarf Stars
• Discovery of a 1.6-year Magnetic Activity Cycle in the Exoplanet Host Star iota Horologii
• The Sun is less active than other solar-like stars
• Optical, UV, and X-Ray Evidence for a 7-Year Stellar Cycle in Proxima Centauri
• Solar-like oscillations with low amplitude in the CoRoT target HD 181906
• Simulating the environment around planet-hosting stars - II. Stellar winds and inner astrospheres
• The exoplanet-host star iota Horologii: an evaporated member of the primordial Hyades cluster
• An X-ray activity cycle on the young solar-like star $\epsilon \mathrm{Eridani}$
• Improving transit characterisation with Gaussian process modelling of stellar variability
• A comprehensive examination of the Eps Eri system -- Verification of a 4 micron narrow-band high-contrast imaging approach for planet searches
• Simulating the Space Weather in the AU Mic System: Stellar Winds and Extreme Coronal Mass Ejections
• The relation between stellar magnetic field geometry and chromospheric activity cycles I: The highly variable field of Epsilon Eridani at activity minimum
• Inflection point in the power spectrum of stellar brightness variations. I. The model
• Proxima Centauri reloaded: Unravelling the stellar noise in radial velocities
• A possible long-term activity cycle for ι Horologii: First results from the HKα & SPI-HKα projects
• Slingshot prominences: coronal structure, mass loss and spin down
• Far beyond the Sun: I. The beating magnetic heart in Horologium
• The corona and upper transition region of epsilon Eridani
• Breezing through the space environment of Barnard's Star b
• Revisiting the space weather environment of Proxima Centauri b
• Time evolution of magnetic activity cycles in young suns: The curious case of kappa Ceti
• Rotation periods from the inflection point in the power spectrum of stellar brightness variations: II. The Sun
• The role and contribution of magnetic fields, characterized via their magnetic flux, to the statistical structuring of the solar atmosphere
• VALD3: current developments
• Inflection point in the power spectrum of stellar brightness variations III: Faculae vs. Spot dominance on stars with known rotation periods
• iota Horologii is unlikely to be an evaporated Hyades star

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