相关论文: An Improved Age-Activity Relationship for Cool Sta…

In low-mass stars, the connection between magnetic activity, rotation period, and age provides key insights into the functioning of dynamos. Fully understanding the activity-rotation-age relationship requires stars with precise fundamental…

Stellar magnetic activity decays over the main-sequence life of cool stars due to the stellar spin-down driven by magnetic braking. The evolution of chromospheric emission is well-studied for younger stars, but difficulties in determining…

We have assembled a sample of $\sim$8200 stars with spectral types F5V-M5V, all having directly measured X-ray luminosities from eROSITA and rotation periods from TESS, and having empirically estimated ages via their membership in stellar…

Accurate stellar dating provides crucial information about the formation and development of planetary systems. Existing age-dating techniques are limited in terms of both the spectral type and age range they can accurately probe, and many…

Stellar magnetic activity provides substantial information on the magnetic dynamo and the coronal heating process. We present a catalog of X-ray activity for about 6000 stars, based on the $Chandra$ and $Gaia$ DR2 data. We also classified…

The ages of the most common stars - low-mass (cool) stars like the Sun, and smaller - are difficult to derive because traditional dating methods use stellar properties that either change little as the stars age or are hard to measure. The…

Active region evolution plays an important role in the generation and variability of magnetic fields on the surface of lower main-sequence stars. However, determining the lifetime of active region growth and decay as well as their evolution…

The knowledge of stellar ages directly impacts the characterization of a planetary system as it puts strong constraints on the moment when the system was born. Unfortunately, the determination of precise stellar ages is a very difficult…

Kepler ultra-high precision photometry of long and continuous observations provides a unique dataset in which surface rotation and variability can be studied for thousands of stars. Because many of these old field stars also have…

We study the four-dimensional relationships between magnetic activity, rotation, mass and age for solar-type stars in the age range 5-25Myr. This is the late-pre-main sequence (l-PMS) evolutionary phase when rapid changes in star's interior…

The coronal activity-rotation relationship is considered to be a proxy for the underlying stellar dynamo responsible for magnetic activity in solar and late-type stars. While this has been studied in considerable detail for…

We study the relation between age and magnetic activity in late-type pre-main sequence (PMS) stars, for the first time using mass-stratified subsamples. The effort is based on the Chandra Orion Ultradeep Project (COUP) which provides very…

The ages of solar-like stars have been at the center of many studies such as exoplanet characterization or Galactic-archaeology. While ages are usually computed from stellar evolution models, relations linking ages to other stellar…

The relationship between age, rotation, and magnetic activity can be used to roughly estimate the ages of solar-type stars. At lower stellar masses, the relationship between activity and age changes due to the less efficient angular…

We study the different patterns of interannual magnetic variability in stars on or near the lower main sequence, approximately solar-type (G-K dwarf) stars in time series of 36 years from the Mount Wilson Observatory Ca\,{\sc ii}\,H\&K…

Magnetic cycles have been detected in tens of solar-like stars. The relationship between the cycle properties and global stellar parameters is not fully understood yet. We searched for activity cycles in 90 solar-like stars with ages…

The vast majority of stars in the nearby stellar neighborhood are M dwarfs. Their low masses and luminosities result in slow rates of nuclear evolution and minimal changes to the star's observable properties, even along astronomical…

The rotation-mass-age relationship offers a promising avenue for measuring the ages of field stars, assuming the attendant uncertainties to this technique can be well characterized. We model stellar angular momentum evolution starting with…

The association of starspots with magnetic fields leads to an expectation that quantities which correlate with magnetic field strength may also correlate with {starspot} coverage. Since younger stars spin faster and are more magnetically…

A sample of 70 magnetically active stars toward the Taurus-Auriga star-forming region has been investigated. The positions of the sample stars on the Rossby diagram have been analyzed. All stars are shown to be in the regime of a saturated…