相关论文: The lithium-rotation correlation for WTTS in Tauru…

Classical T Tauri stars are young low-mass systems still accreting material from their disks. These systems are dynamic on timescales of hours to years. The observed variability can help us infer the physical processes that occur in the…

We address the existence and origin of the lithium (Li) desert, a region in the Li - T_eff plane sparsely populated by stars. Here we analyze some of the explanations that have been suggested for this region, including mixing in the late…

We present an analysis of the Chandra High Energy Transmission Grating Spectrometer observation of the rapidly rotating P_(rot)=0.94 d post T Tauri (~20 Myr old) star PZ Telescopii, in the Tucana association. Using two different methods we…

A lithium depletion boundary is detected in HIP 112312 (GJ 871.1 A and B), a \~12 Myr old pre-main sequence binary system. A strong (EW 300 mA) Li 6708 A absorption feature is seen at the secondary (~M4.5) while no Li 6708 A feature is…

We investigate the distribution of the lithium abundances, A(Li), of metal-poor dwarf and subgiant stars within the limits 5500 K < Teff < 6700 K, -6.0 < [Fe/H] < -1.5, and logg > ~3.5 (a superset of parameters first adopted by Spite and…

The lithium abundances for 378 G/K giants are derived with non-LTE correction considered. Among these, there are 23 stars that host planetary systems. The lithium abundance is investigated, as a function of metallicity, effective…

Since 7Li is easily destroyed in low temperatures, the surface lithium abundance decreases as stars evolve. This is supported by the lithium depletion observed in the atmosphere of most red giants. However, recent studies show that almost…

Lithium-rich giant stars are rare and their existence challenges our understanding of stellar structure and evolution. We profit from the high-quality sample gathered with HARPS and UVES, in order to search for Li-rich giants and to…

We present a catalog of ~100,000 periodic variable stars in TESS FFI data among members of widely distributed moving groups identified with Gaia in the previous papers in the series. By combining the periods from our catalog attributable to…

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…

Observing ROSAT sources in 20 x 25 deg centered at the high latitude active star ER Eri, we found evidences for a new young nearby association (~30Myr at~60pc), the Horologium Association (HorA), formed by at least 10 probable and 6…

We have determined precise stellar parameters and lithium abundances in a sample of 117 stars with basic properties very similar to the Sun. This sample selection reduces biasing effects and systematic errors in the analysis. We estimate…

Context. Classical T Tauri stars (cTTs) are pre-main sequence stars surrounded by an accretion disk. They host a strong magnetic field, and both magnetospheric accretion and ejection processes develop as the young magnetic star interacts…

The chemical composition of the Sun is still a highly controversial issue. No solar model has yet been able to simultaneously reproduce the solar lithium and beryllium abundances, along with helioseismic results, including the rotation…

We review the current state of our knowledge concerning the rotation and angular momentum evolution of young stellar objects and brown dwarfs from a primarily observational view point. Periods are typically accurate to 1% and available for…

The application to main-sequence stars of the rotation-induced mixing theory in the presence of mu-gradients leads to partial mixing in the lithium destruction region, not visible in the atmosphere. The induced lithium depletion becomes…

We have analyzed a sample of 74 magnetically active stars toward the Taurus-Auriga star-forming region. Based on accurate data on their basic physical parameters obtained from original photometric observations and published data on their…

Recent observational work by Israelian et al. has shown that sun-like planet host stars in the temperature range 5700K < Teff < 5850K have lithium abundances that are significantly lower than those observed for "single" field stars. In this…

Interpreting the short-timescale variability of the accreting, young, low-mass stars known as Classical T Tauri stars remains an open task. Month-long, continuous light curves from the Transiting Exoplanet Survey Satellite (\textit{TESS})…

As part of the Young Exoplanets Spectroscopic Survey (YESS), this study explores the spot variability of 13 T Tauri Stars (TTSs) in the near-infrared $H$ band, using spectra from the Immersion GRating INfrared Spectrometer (IGRINS). By…