514 datasets found

Several samples of nearby stars with the most accurate astrometric and photometric parameters are searched for clues to their evolutionary history. The main samples are (1) the...

300 trigonometric parallaxes, 15 revised binary-star orbits, and 24 mass ratios are listed and annotated. Cone search capability for table J/AJ/108/2338/table1 (Proper motions...

Trigonometric parallaxes, relative proper motions, and photometry are presented for 122 stars in 111 systems. Of these stars, 70 are brighter than V = 10.0. Cone search...

The U.S. Naval Observatory CCD trigonometric parallax program is described in detail, including the instrumentation employed, observing procedures followed, and reduction...

Mean proper motions and parallaxes of 205 open clusters were determined from their member stars found in the Hipparcos () Catalogue. 360 clusters were searched for possible...

We present improved Hipparcos astrometry for 257 Hipparcos stars, resolved into 342 components. For 64 of the stars no astrometry was obtained in the Hipparcos Catalogue, while...

We present the results from a spectroscopic CaII H&K survey of 1058 late-type stars selected from a color-limited subsample of the Hipparcos (Cat. ) catalog. Out of these...

Hipparcos data for 71 nearby dwarf A0 stars were combined with other data, in particular with high resolution spectra to establish the HR diagram in this temperature range....

We give 139 reprocessed problem double stars using Hipparcos data Cone search capability for table J/A+AS/135/231/table3 (Hipparcos solution with time dependent proper motion...

Unresolved binaries in star clusters can bias stellar and cluster mass estimates, making their proper treatment essential for studying cluster dynamics and evolution. We aim to...

Type II Cepheids are pulsating stars that can be used as standard candles for old stellar populations due to their characteristic Period-Luminosity and Period-Luminosity-Colour...

Binary stars containing a white dwarf and a main-sequence star, WDMS binaries, can be used to study a wide range of aspects of stellar astrophysics. We build a magnitude-limited...

Local young stellar associations (LYSAs <50Myr and <150pc) are important laboratories to test predictions from star formation theories. Estimating their ages through...

Direct imaging (DI) campaigns are uniquely suited to probing the outer regions around young stars and looking for giant exoplanet and brown dwarf companions, hence providing key...

Open clusters that emerged from the star forming regions as gravitationally bound structures are subjected to star evaporation, ejection, and tidal forces throughout the rest of...

The complex dynamics of asymptotic giant branch (AGB) stars and the resulting stellar winds have a significant impact on the measurements of stellar parameters and amplify their...

Since the first publication of the Gaia catalogue a new view of our Galaxy has arrived. Its astrometric and photometric information has improved the precision of the physical...

We present the first volume-limited sample of spectroscopically confirmed hot subluminous stars out to 500pc, defined using the accurate parallax measurements from the Gaia...

In a previous paper using Gaia DR2 data, we demonstrated that the two closely situated open clusters Collinder 135 and UBC 7 might have formed together about 50Myr ago. In this...

Stars that are found on the blue horizontal-branch (BHB) evolved from low-mass stars that have completed their core hydrogen-burning main sequence (MS) stage and undergone the...