Related papers: Activity cycles in RS CVn type stars

Measuring surface differential rotation (DR) on different types of stars is important when characterizing the underlying stellar dynamo. It has been suggested that anti-solar DR laws can occur when strong meridional flows exist. We aim to…

Inhibition of the convective blueshift in active regions is a major contribution to the radial velocity variations, at least for solar-like stars. A common technique to correct for this component is to model the RV as a linear function of…

We present an observational program we started in 1999, to systematically obtain mid-resolution spectra of late-type stars, to study in particular chromospheric activity. In particular, we found cyclic activity in four dM stars, including…

More than 450 exoplanets have currently been detected, most of them by the radial velocity (RV) technique. While the majority of exoplanets have been found around main-sequence (MS) FGK stars (M 1.5M*), only a small fraction (- 10%) have…

RAVE, the unbiased magnitude limited survey of the southern sky stars, contained 456,676 medium-resolution spectra at the time of our analysis. Spectra cover the CaII IRT range which is a known indicator of chromospheric activity. Our…

The connection between stellar rotation, stellar activity, and convective turnover time is revisited with a focus on the sole contribution of magnetic activity to the Ca II H&K emission, the so-called excess flux, and its dimensionless…

We present chromospheric CaII activity measurements, rotation periods and ages for ~1200 F-, G-, K-, and M- type main-sequence stars from ~18,000 archival spectra taken at Keck and Lick Observatories as a part of the California and Carnegie…

Based on the Ca\,II H and K lines observed by LAMOST, we employ the photospheric ($R'_{\rm HK}$) and basal ($R^+_{\rm HK,L}$) flux calibrated chromospheric activity indices to examine the relationship between chromospheric activity and the…

Solar simulations and observations show that the detection of long-period Earth-like planets is expected to be very difficult with radial velocity techniques in the solar case because of activity. The inhibition of the convective blueshift…

Rapidly rotating giant stars are relatively rare and may represent important stages of stellar evolution, resulting from stellar coalescence of close binary systems or accretion of sub-stellar companions by their hosting stars. In the…

Spectroscopic monitoring of 141 southern field B type stars, 114 of them known to exhibit the Be phenomenon, allowed the estimation of their projected rotational velocities, effective temperatures and superficial gravities from…

We present a study of high-resolution spectra of RS Canum Venaticorum (RS CVn), a prototype of active binary systems. Our data were obtained from 1998 to 2017 using different telescopes. We analyze the chromospheric activity indicators Ca…

A large sample of over 38,000 chromospherically active candidate solar-like stars and cooler dwarfs from the RAVE survey is addressed in this paper. An improved activity identification with respect to the previous study was introduced to…

Using a time series of high-resolution spectra and high-quality multi-colour photometry, we reconstruct surface maps of the primary component of the RS CVn type rapidly rotating eclipsing binary, SV Cam (F9V + K4V). We measure a mass ratio,…

Aims: We present a compilation of spectroscopic data from a survey of 144 chromospherically active young stars in the solar neighborhood which may be used to investigate different aspects of the formation and evolution of the solar…

V-band time-series CCD photometric observations of the intermediate-age open cluster M11 were performed to search for variable stars. Using these time-series data, we carefully examined light variations of all stars in the observing field.…

The eleven year solar cycle is known to affect the global modes of solar acoustic oscillations. In particular, p mode frequencies increase with solar activity. We propose a new method to detect the solar cycle from the p-mode…

We report the discovery of 141 new high proper motion systems (1.0"/yr > mu >= 0.4"/yr) in the southern sky (Declination = -90 degrees to -47 degrees) brighter than UKST plate R_{59F} = 16.5 via our SuperCOSMOS-RECONS (SCR) search. When…

This study presents the rotational distribution of red giant stars (RGs) in eleven old to intermediate age open clusters. The masses of these stars are all above the Kraft break, so that they lose negligible amounts of their birth angular…

Stars of stellar type later than about M3.5 are believed to be fully convective and therefore unable to support magnetic dynamos like the one that produces the 11-year solar cycle. Because of their intrinsic faintness, very few late M stars…