Search Publications
CCD photometric search for peculiar stars in open clusters. IV. Collinder 272, Pismis 20, Lyng\aa 14, NGC 6396 and NGC 6611
Paunzen, E.; Maitzen, H. M.; Pintado, O. I.
The time scale on which chemical peculiarity in upper main sequence stars begins is unknown. Results from the Hipparcos measurements indicate that the classical chemically peculiar (CP) stars occupy the whole area from the zero age main sequence to the terminal age main sequence (Gómez et al. \cite{Gom98}). However, Hubrig et al. (\cite{Hub00}) re…
The enigmatic WR46: A binary or a pulsator in disguise. I. The photometry
Sterken, C.; van der Hucht, K. A.; van Genderen, A. M. +3 more
We discuss the observational history of the Wolf-Rayet object WR 46 (WN3p), including a re-investigation of the original discovery plates from early this century. We find that the reported presence of N Iii lines is a mis-interpretation of N V lines and conclude that the object did not change its spectral type since the first recording one century…
Dark matter revealed. More evidence from faint-star proper-motions for a cool and warm component of the local dark matter in the Galaxy
Méndez, R. A.
We present new evidence, based on faint HST proper-motions, for a bi-modal kinematic population of old white dwarfs, representative of the Thick-Disk and Halo of our Galaxy. This evidence supports the idea of a massive Halo comprised of faint and old white dwarfs, along with an extant population of Thick-Disk white dwarfs. We show how most of the …
The pulsation modes and masses of carbon-rich long period variables
Bergeat, J.; Knapik, A.; Rutily, B.
Following our study of the carbon-rich giants in the HR diagram and of their luminosity function (Paper III), we investigate the pulsation data of the long period variables (LPVs) included in our sample. Pulsation modes (fundamental, overtone(s)) for carbon LPVs are identified in the period-radius diagram, making use of observed bi-periodicity in …
Study of the Per OB2 star-forming complex. I. The Compiled Catalogue of kinematic and photometric data
Scholz, R. -D.; Yatsenko, A. I.; Piskunov, A. E. +3 more
In this paper we describe the construction of a Compiled Catalogue (CC) of about 30 000 stars in a nearby region of star formation including the Per OB2 association. The CC is a photometric and astrometric survey with the center at (alpha ,delta )_J2000=(3h51m36s, 34o36arcmin ) and radius of 10 degrees. …
Systematic errors in measuring solar magnetic fields with a FPI spectrometer and MDI
Carroll, T. A.; Norton, A. A.; Settele, A. +1 more
We will show the potential errors of observations using instruments, where a line spectrum is obtained not instantly but by scanning through the spectral line in time. We give two examples in simulations of a sunspot observation with the measuring procedure of a typical Fabry-Perot interferometer (FPI) spectrometer and the Michelson Doppler Imager…
A revision of the fundamental parameters of the open cluster Hogg 15 and the projected star WR 47
Bica, E.; Piatti, A. E.; Santos, J. F. C., Jr. +1 more
We revise the fundamental parameters of the faint open cluster Hogg 15, for which two recent colour-magnitude diagram (CMD) studies have obtained significantly different ages. In the present study, we combine a series of methods trying to constrain age, together with other fundamental parameters. We employ spatial extractions to construct the CMDs…
XMM-Newton observation of the bursting pulsar GRO J1744-28 in quiescence
Goldoni, P.; Decourchelle, A.; Warwick, R. S. +3 more
The XMM-Newton X-ray observatory performed a pointed observation of the bursting pulsar GRO J1744-28 in April 2001 for about 10 ks during a program devoted to the scan of the Galactic center region. After the discovery of this source by BATSE in December 1995 during a very active bursting phase, it has been in quiescence since April 1997. We prese…
NGC 6994 - clearly not a physical stellar ensemble
Soubiran, C.; Odenkirchen, M.
The sparse stellar ensemble NGC 6994 = M 73 has recently been discussed as a possible remnant of an old open cluster. In order to solve the controversy regarding the nature of this object we have taken high-resolution spectra of the six brightest stars within 6' angular distance of its nominal position. These stars are the only obvious candidate m…
Asteroid (216) Kleopatra. Tests of the radar-derived shape model
Lattanzi, M.; Tanga, P.; Berthier, J. +5 more
The shape model of Ostro et al. (\cite{ostro00}) for