Related papers: Stellar activity cycles and asteroseismology
The last solar minimum was, by recent standards, unusually deep and long. We are now close to the maximum of the subsequent solar cycle, which is relatively weak. In this article we make comparisons between different global (unresolved)…
We use Sun-as-a-star helioseismology data, collected by the Birmingham Solar-Oscillations Network (BiSON), to examine the relationship between the solar-cycle-induced frequency shifts of whole-Sun, low-angular degree solar p modes and…
Aims. We aim studying the use of cross-correlation techniques to infer the frequency shifts induced by changing magnetic fields in the p-mode frequencies and provide precise estimation of the error bars. Methods. This technique and the…
The parameters of the p-mode oscillations vary with solar activity. Such temporal variations provide insights for the study of the structural and dynamical changes occurring in the Sun's interior throughout the solar cycle. We present here…
We study the response of the low-degree solar p-mode frequencies to the unusual extension of the minimum of solar surface activity since 2007. Helioseismic observations collected by the space-based, Sun-as-a-star GOLF instrument and by the…
Frequency separations used to infer global properties of stars through asteroseismology can change depending on the strength and at what epoch of the stellar cycle the p-mode frequencies are measured. In the Sun these variations have been…
The Sun's magnetic dynamo cycle features a distinct pattern: a propagating region of sunspot emergence appears around 30 degrees latitude and vanishes near the equator every 11 years. Moreover, longitudinal flows called "torsional…
Solar differential rotation exhibits a prominent feature: its cyclic variations over the solar cycle, referred to as zonal flows or torsional oscillations, are observed throughout the convection zone. Given the challenge of measuring…
The Mount Wilson Ca HK survey revealed magnetic activity variations in a large sample of solar-type stars with timescales ranging from 2.5 to 25 years. This broad range of cycle periods is thought to reflect differences in the rotational…
The aim of this paper is to investigate whether there are any 11-yr or quasi-biennial solar cycle-related variations in solar rotational splitting frequencies of low-degree solar p modes. Although no 11-yr signals were observed, variations…
We present the results of an investigation into the possible presence of magnetic activity cycles in stars observed in two observational campaigns by the K2 mission. This study was based on the KEYSTONE asteroseismic sample of solar-like…
The presence of intense magnetic fields in and around sunspots is expected to modify the solar structure and oscillation frequencies. Applying the ring diagram technique to data from the Michelson Doppler Imager (MDI) on board the Solar and…
In addition to the well-known 11-year solar cycle, the Sun's magnetic activity also shows significant variation on shorter time scales, e.g. between one and two years. We observe a quasi-biennial (2-year) signal in the solar p-mode…
Observations of stellar activity cycles provide an opportunity to study magnetic dynamos under many different physical conditions. Space-based asteroseismology missions will soon yield useful constraints on the interior conditions that…
Magnetic activity is a ubiquitous feature of stars with convective outer layers, with implications from stellar evolution to planetary atmospheres. Investigating the mechanisms responsible for the observed stellar activity signals from days…
We have analyzed the full set of SOHO/MDI f- and p-mode oscillation frequencies from 1996 to date in a search for evidence of solar radius evolution during the rising phase of the current activity cycle. Like Antia et al. (2000), we find…
Seismic analyses of the CoRoT target HD 49933 have revealed a magnetic cycle. Further insight reveals that frequency shifts of oscillation modes vary as a function of frequency, following a similar pattern to that found in the Sun. In this…
Aims. The Sun shows strong variability in its magnetic activity, from Grand minima to Grand maxima, but the nature of the variability is not fully understood, mostly because of the insufficient length of the directly observed solar activity…
We study the response of the low-degree, solar p-mode frequencies to the unusually extended minimum of solar surface activity since 2007. A total of 4768 days of observations collected by the space-based, Sun-as-a-star helioseismic GOLF…
We looked for signatures of Quasi-Biennial Periodicity (QBP) over different phases of solar cycle by means of acoustic modes of oscillation. Low-degree p-mode frequencies are shown to be sensitive to changes in magnetic activity due to the…