Related papers: The Decay of Stellar Dynamos and X-ray Activity
Stellar activity can be observed at different wavelengths in a variety of different activity indicators. We investigated the correlation between coronal and chromospheric emissions by combining X-ray data from stars detected in the eROSITA…
AIMS. While observational evidence shows that most of the decline in a star's X-ray activity occurs between the age of the Hyades (~8 x 10^8 yrs) and that of the Sun, very little is known about the evolution of stellar activity between…
Stars with convective envelopes display magnetic activity, which decreases over time due to the magnetic braking of the star. This age-dependence of magnetic activity is well-studied for younger stars, but the nature of this dependence for…
We present an analysis of the ultraluminous X-ray source (ULX) population in 75 Virgo cluster late-type galaxies, including all those with a star formation rate >~ 1 M_{sun}/yr and a representative sample of the less star-forming ones. This…
Based on a homogeneous set of X-ray, infrared and ultraviolet observations from Chandra, Spitzer, GALEX and 2MASS archives, we study populations of high-mass X-ray binaries (HMXBs) in a sample of 29 nearby star-forming galaxies and their…
An update is given on the current status of solar and stellar dynamos. At present, it is still unclear why stellar cycle frequencies increase with rotation frequency in such a way that their ratio increases with stellar activity. The…
Aims. We study the evolution of rotation and high energy X-ray, extreme ultraviolet (EUV), and Ly-alpha emission for F, G, K, and M dwarfs, with masses between 0.1 and 1.2 Msun, and provide our evolutionary code and a freely available set…
Measuring the evolution of X-ray emission from pre-main sequence (PMS) stars gives insight into two issues: the response of magnetic dynamo processes to changes in interior structure and the effects of high-energy radiation on…
We present 348 X-ray emitting stars identified from correlating the Extended Chandra Multiwavelength Project (ChaMP), a serendipitous wide-area X-ray survey, with the Sloan Digital Sky Survey (SDSS). We use morphological star/galaxy…
Observations of magnetic activity indicators in solar-type stars exhibit a relationship with rotation with an increase until a "saturation" level and a moderate decrease in activity in the very fastest rotators ("supersaturation"). While…
This article presents the construction and validation of complete stellar mass-selected, volume-limited galaxy samples using the Legacy Survey (data release 10) galaxy catalogs, covering $\sim16,800$ deg$^2$ of extra-galactic sky, and…
Using the results of our first paper on the Chandra HRC observation of the Orion Nebula Cluster (ONC), here we explore the relation between the coronal activity of its 1-Myr-old pre-main sequence population and stellar parameters. We find…
Precise photometry from the Kepler space telescope allows not only the measurement of rotation in solar-type field stars, but also the determination of reliable masses and ages from asteroseismology. These critical data have recently…
Stellar mass loss rates are an important input ingredient for stellar evolution models since they determine stellar evolution parameters such as stellar spin-down and increase in stellar luminosity through the lifetime of a star. Due to the…
We analyze the X-ray emission and chromospheric activity of Sun-like stars of F, G and K spectral classes (late-type stars) studied in the framework of the HK project. More powerful coronas are possessed by stars displaying irregular…
Optical and near-IR observations of the halos of disk galaxies and blue compact galaxies have revealed a very red spectral energy distribution, which cannot easily be reconciled with a normal, metal-poor stellar population like that in the…
We have modeled the displacement of luminous X-ray binaries from star clusters in star-burst galaxies with an evolutionary population synthesis code developed by Hurley et al. (2000, 2002). In agreement with Kaaret et al. (2004), we find…
We present a brief review of observational results contributing to modern ideas on the evolution of stellar activity. Basic laws, derived for both rotation-age and activity-rotation relationships, allow us to trace how the activity of…
We present an X-ray binary population synthesis model, and use it to simulate the evolution of X-ray binaries formed in a burst of star formation of duration 20 Myr and star-formation rate 10 M_sun/yr. Our goal is to explain the hard (2-10…
Like the solar cycle, stellar activity cycles are also irregular. Observations reveal that rapidly rotating (young) Sun-like stars exhibit a high level of activity with no Maunder-like grand minima and rarely display smooth regular activity…