Detecting active latitudes of Sun-like stars using asteroseismic a-coefficients
arXiv:2308.08779 · doi:10.1051/0004-6361/202347095
Abstract
We introduce a framework to measure the asphericity of Sun-like stars using , and coefficients, and constrain their latitudes of magnetic activity. Systematic errors on the inferred coefficients are evaluated in function of key physical and seismic parameters (inclination of rotation axis, average rotation, height-to-noise ratio of peaks in power spectrum). The measured a-coefficients account for rotational oblateness and the effect of surface magnetic activity. We use a simple model that assumes a single latitudinal band of activity. Using solar SOHO/VIRGO/SPM data, we demonstrate the capability of the method to detect the mean active latitude and its intensity changes between 1999-2002 (maximum of activity) and 2006-2009 (minimum of activity). We further apply the method to study the solar-analogue stars 16 Cyg A and B using Kepler observations. An equatorial band of activity, exhibiting intensity that could be comparable to that of the Sun, is detected in 16 Cyg A. However, 16 Cyg B exhibits a bi-modality in that is challenging to explain. We suggest that this could be a manifestation of the transition between a quiet and an active phase of activity. Validating or invalidating this hypothesis may require new observations.
arXiv commentAccepted to A&A
References in corpus (53)
- The PLATO 2.0 Mission
- The Discovery of a Planetary Companion to 16 Cygni B
- Weakened magnetic braking as the origin of anomalously rapid rotation in old field stars
- Testing Scaling Relations for Solar-Like Oscillations from the Main Sequence to Red Giants using Kepler Data
- Seismic evidence for a rapidly rotating core in a lower-giant-branch star observed with Kepler
- Seismic constraints on the radial dependence of the internal rotation profiles of six Kepler subgiants and young red giants
- Calculating asteroseismic diagrams for solar-like oscillations
- Preparation of Kepler lightcurves for asteroseismic analyses
- Standing on the shoulders of Dwarfs: the asteroseismic LEGACY sample I - oscillation mode parameters
- Probing the core structure and evolution of red giants using gravity-dominated mixed modes observed with Kepler
- Determining global parameters of the oscillations of solar-like stars
- Inferring the eccentricity distribution
- Asteroseismology of the solar analogs 16 Cyg A & B from Kepler observations
- Multiple and changing cycles of active stars II. Results
- Core rotation braking on the red giant branch for various mass ranges
- Interferometric radii of bright Kepler stars with the CHARA Array: θ Cygni and 16 Cygni A and B
- Stellar Evidence that the Solar Dynamo may be in Transition
- Acoustic oscillations in rapidly rotating polytropic stars I. Effects of the centrifugal distortion
- Bayesian peak-bagging of solar-like oscillators using MCMC: A comprehensive guide
- Nearly-uniform internal rotation of solar-like main-sequence stars revealed by space-based asteroseismology and spectroscopic measurements
- Asteroseismic inference on rotation, gyrochronology and planetary system dynamics of 16 Cygni
- Surface rotation of Kepler red giant stars
- Asteroseismic detection of latitudinal differential rotation in 13 Sun-like stars
- γ Doradus stars as test of angular momentum transport models
- Properties of starspots on CoRoT-2
- Observing the Sun with the Atacama Large Millimeter-submillimeter Array (ALMA): Fast-Scan Single-Dish Mapping
- Detailed Abundances of the Solar Twins 16 Cygni A and B: Constraining Planet Formation Models
- Seismic constraints on rotation of Sun-like star and mass of exoplanet
- Magnetic cycles at different ages of stars
- The art of fitting p-mode spectra: Part I. Maximum Likelihood Estimation
- Visibilities and bolometric corrections for stellar oscillation modes observed by Kepler
- Spin-orbit alignment of exoplanet systems: ensemble analysis using asteroseismology
- Asteroseismic estimate of helium abundance of a solar analog binary system
- Asteroseismology from multi-month Kepler photometry: the evolved Sun-like stars KIC 10273246 and KIC 10920273
- Asteroseismic inference on the spin-orbit misalignment and stellar parameters of HAT-P-7
- Oscillation mode linewidths and heights of 23 main-sequence stars observed by Kepler
- Revisiting the 16 Cygni planet host at unprecedented precision and exploring automated tools for precise abundances
- Accretion of planetary matter and the lithium problem in the 16 Cygni stellar system
- Model-independent measurement of internal stellar structure in 16 Cygni A and B
- Using seismic inversions to obtain an internal mixing processes indicator for main-sequence solar-like stars
- Masses of subgiant stars from asteroseismology using the coupling strengths of mixed modes
- Latitudinal differential rotation in the solar analogues 16 Cyg A and B
- Thorough characterisation of the 16 Cygni system Part I: Forward seismic modelling with WhoSGlAd
- Simulations of Oscillation Modes of the Solar Convection Zone
- Shape of a slowly rotating star measured by asteroseismology
- Limits on radial differential rotation in Sun-like stars from parametric fits to oscillation power spectra
- Anomalies in the Kepler Asteroseismic Legacy Project Data. A re-analysis of 16 Cyg A&B, KIC8379927 and 6 solar-like stars
- Testing abundance-age relations beyond solar analogues with Kepler LEGACY stars
- Thorough characterisation of the 16 Cygni system. Part II. Seismic inversions of the internal structure
- The acoustic low-degree modes of the Sun measured with 14 years of continuous GOLF & VIRGO measurements
- Asymmetry of line profiles of stellar oscillations measured by Kepler for ensembles of solar-like oscillators: impact on mode frequencies and dependence on effective temperature
- Uncertainties and biases in modelling 16 Cyg A and B
- Asteroseismic Signature of a Large Active Region