Add to ORKGWe present archival ROSAT data for three recently identified, nearby (D<70 pc), young (~10-40 Myr) stellar associations: the TW Hydrae Association, the Tucana Association, and the beta Pic Moving Group. The distributions of ROSAT X-ray hardness ratios (HR1, HR2) for these three groups, whose membership is dominated by low-mass, weak-lined T Tauri stars, are tightly clustered and very similar to one another. The value of HR1 for TW Hya itself -- the only bona fide classical T Tauri star in any of the nearby groups -- is clearly anomalous among these nearby young stars. Excluding TW Hya, the hardness ratio distributions of stars in all three nearby groups are distinct from those of weak-lined and classical T Tauri stars in Taurus and from tho...
Context. Measurements of the fraction of disk-bearing stars in clusters as a function of age indicat...
In Chapter I, I introduce the framework of observational and theoretical evidence that has been cons...
This thesis work presents the physical and kinematical characterization of X-ray active and presumed...
We present archival ROSAT data for three recently identified, nearby (D \u3c 70 pc), young (~10−40 M...
With ground-based optical follow-up observations of previously unidentified ROSAT All-Sky-Survey X-r...
Post T Tauri stars (PTTS) are late-type stars in the age range between 10 and 100 Myr filling the ga...
The X-ray properties of classical and weak-lined T Tauri stars are briefly reviewed, emphasizing rec...
Abstract. We present results of intermediate resolution spectroscopy of 131 optical counterparts to ...
Post-T Tauri stars (PTTSs) are low-mass, pre-MS stars which have ceased accreting, and are not neces...
To investigate the formation and early evolution of stars, astronomers study the x-ray emission of T...
We analyse the nature of the optical counterparts of the ROSAT all-sky survey (RASS) X-ray sources i...
To investigate the potential connection between the intense X-ray emission from young low-mass stars...
Received; accepted Context. The associations and moving groups of young stars are excellent laborato...
International audienceIn a recent study, individual parallaxes were determined for many stars of the...
We report the results of our radial velocity monitoring of spectroscopic binary systems in a sample ...
Context. Measurements of the fraction of disk-bearing stars in clusters as a function of age indicat...
In Chapter I, I introduce the framework of observational and theoretical evidence that has been cons...
This thesis work presents the physical and kinematical characterization of X-ray active and presumed...
We present archival ROSAT data for three recently identified, nearby (D \u3c 70 pc), young (~10−40 M...
With ground-based optical follow-up observations of previously unidentified ROSAT All-Sky-Survey X-r...
Post T Tauri stars (PTTS) are late-type stars in the age range between 10 and 100 Myr filling the ga...
The X-ray properties of classical and weak-lined T Tauri stars are briefly reviewed, emphasizing rec...
Abstract. We present results of intermediate resolution spectroscopy of 131 optical counterparts to ...
Post-T Tauri stars (PTTSs) are low-mass, pre-MS stars which have ceased accreting, and are not neces...
To investigate the formation and early evolution of stars, astronomers study the x-ray emission of T...
We analyse the nature of the optical counterparts of the ROSAT all-sky survey (RASS) X-ray sources i...
To investigate the potential connection between the intense X-ray emission from young low-mass stars...
Received; accepted Context. The associations and moving groups of young stars are excellent laborato...
International audienceIn a recent study, individual parallaxes were determined for many stars of the...
We report the results of our radial velocity monitoring of spectroscopic binary systems in a sample ...
Context. Measurements of the fraction of disk-bearing stars in clusters as a function of age indicat...
In Chapter I, I introduce the framework of observational and theoretical evidence that has been cons...
This thesis work presents the physical and kinematical characterization of X-ray active and presumed...