相关论文: Rotation in NGC 2264: a study based on CoRoT photo…

Context. The rotation period of stars is an important parameter along with mass, radius, effective temperature. It is an essential parameter for any radial velocity monitoring, as stellar activity can mimic the presence of a planet at the…

Studies of planetary systems of stars in star-forming regions and young clusters open a window on the formative stages of planetary evolution. We obtained high-cadence high-resolution infrared spectroscopy of the solar-mass Taurus…

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…

The main goal of this work is to characterize the mass accretion and ejection processes of the classical T Tauri star V354 Mon, a member of the young stellar cluster NGC 2264. In March 2008, photometric and spectroscopic observations of…

We report on the results of a time-series photometric survey of M50 (NGC 2323), a ~130 Myr open cluster, carried out using the CTIO 4m Blanco telescope and Mosaic-II detector as part of the Monitor project. Rotation periods were derived for…

Pulsars are rotating neutron stars that are seen to slow down, and the spin-down rate is thought to be due to magnetic dipole radiation. This leads to a prediction for the braking index n, which is a combination of spin period and its first…

We have modeled the rotational modulation of X-ray emission from T Tauri stars assuming that they have isothermal, magnetically confined coronae. By extrapolating surface magnetograms we find that T Tauri coronae are compact and clumpy,…

High precision photometry and spectroscopy of low-mass stars reveal a variety of properties standard stellar evolution cannot predict. Rotation, an essential ingredient of stellar evolution, is a step towards resolving the discrepancy…

Rotation period measurements of stars observed with the Kepler mission have revealed a lack of stars at intermediate rotation periods, accompanied by a decrease of photometric variability. Whether this so-called dearth region is a…

Angular momentum distribution and its redistribution are of crucial importance in formation and evolution of circumstellar disks. Many molecular line observations toward young stellar objects indicate that radial distributions of the…

We present the results of dust continuum and molecular line observations of two massive cluster-forming clumps, NGC 2264-C and NGC 2264-D, including extensive mapping performed with the MAMBO bolometer array and the HERA heterodyne array on…

A sample of 97 galactic field Be stars were studied by taking into account the effects induced by the fast rotation on their fundamental parameters. All program stars were observed in the BCD spectrophotometric system in order to minimize…

We report new photometric observations of the 200000 year old naked weak-line run-away T Tauri star Par 1724, located north of the Trapezium cluster in Orion. We observed in the broad band filters B, V, R, and I using the 90cm Dutch…

We provide a status report on the determination of stellar ages from asteroseismology for stars of various masses and evolutionary stages. The ability to deduce the ages of stars with a relative precision of typically 10 to 20% is a unique…

Accurate surface rotation measurements are crucial to estimate stellar ages and improve our understanding of stellar rotational evolution. Comparisons of datasets obtained from different space missions on common targets represent in this…

We present the results of a detailed kinematic analysis of a significant fraction of the known population of Galactic star clusters aimed at constraining the physical mechanisms driving the onset and evolution of cluster rotation. Our study…

The recent variability survey of the NGC 3766 cluster revealed a considerable number of periodic variable stars in a region of the H-R diagram where no pulsation is expected. This region lies between the instability strips of the delta…

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…

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…

We present results of a Chandra observation of a field in NGC 2264. The observations were taken with the ACIS-I camera with an exposure time of 48.1 ks. We present a catalog of 263 sources, which includes X-ray luminosity, optical and…