Related papers: Sounding stellar cycles with Kepler - II. Ground-b…
We report the latest view of Kepler solar-type (G-type main-sequence) superflare stars, including recent updates with Apache Point Observatory (APO) 3.5m telescope spectroscopic observations and Gaia-DR2 data. First, we newly conducted…
The Kepler mission, launched in March 2009, has revolutionized asteroseismology, providing detailed observations of thousands of stars. This has allowed in-depth analysis of stars ranging from compact hot subdwarfs to red giants, and…
Our knowledge of magnetic activity of stars is mostly based on the study of the Sun and some spectroscopic surveys of a few hundreds of stars. However, the detailed mechanisms of the solar magnetic activity cycle are not fully understood.…
The stellar magnetic field plays a crucial role in the star internal mechanisms, as in the interactions with its environment. The study of starspots provides information about the stellar magnetic field, and can characterise the cycle.…
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…
Photometry from the Kepler mission is optimized to detect small, short duration signals like planet transits at the expense of long-term trends. This long-term variability can be recovered in photometry from the Full Frame Images (FFIs), a…
The primary science goal of the Kepler Mission is to provide a census of exoplanets in the solar neighborhood, including the identification and characterization of habitable Earth-like planets. The asteroseismic capabilities of the mission…
The field of asteroseismology has enjoyed a large swath of data coming from recent missions (e.g., CoRoT, Kepler, K2). This wealth of new data has allowed the field to expand beyond the previous limitation of a few extremely bright and…
Solar analogs, stars that closely match the fundamental properties of the Sun, provide key benchmarks for testing stellar structure and evolution across different ages and activity levels. Their detailed characterization helps place the Sun…
We report on the first asteroseismic analysis of solar-type stars observed by Kepler. Observations of three G-type stars, made at one-minute cadence during the first 33.5d of science operations, reveal high signal-to-noise solar-like…
We use asteroseismic data from the Kepler satellite to determine fundamental stellar properties of the 66 main-sequence targets observed for at least one full year by the mission. We distributed tens of individual oscillation frequencies…
We report spectroscopic observations of 23 candidates for Kepler asteroseismic targets and 10 other stars in the Kepler field, carried out at two observatories (see the footnote). For all these stars, we derive the radial velocities,…
During the survey phase of the Kepler mission, several thousands of stars were observed in short cadence, allowing the detection of solar-like oscillations in more than 500 main-sequence and sub-giant stars. Later, the Kepler Science Office…
In recent years it has been claimed that the length of stellar activity cycles is determined by the stellar rotation rate. It is observed that the cycle period increases with rotation period along the so-called active and inactive…
The length of the asteroseismic timeseries obtained from the Kepler satellite analysed here span 19 months. Kepler provides the longest continuous timeseries currently available, which calls for a study of the influence of the increased…
It is believed that magnetic activity on the Sun and solar-type stars are tightly related to the dynamo process driven by the interaction between rotation, convection, and magnetic field. However, the detailed mechanisms of this process are…
Kepler-30 is a unique target to study stellar activity and rotation in a young solar-like star accompanied by a compact planetary system. We use about 4 years of high-precision photometry collected by the Kepler mission to investigate the…
The frequency, $\nu_{\rm max}$, at which the envelope of pulsation power peaks for solar-like oscillators is an important quantity in asteroseismology. We measure $\nu_{\rm max}$ for the Sun using 25 years of Sun-as-a-Star Doppler velocity…
The Kepler space telescope observed over 15,000 stars for asteroseismic studies. Of these, 75% of dwarfs (and 8% of giants) were found to show anomalous behavior: such as suppressed oscillations (low amplitude) or no oscillations at all.…
The solar magnetic activity cycle is responsible for periodic episodes of severe space weather, which can perturb satellite orbits, interfere with communications systems, and bring down power grids. Much progress has recently been made in…