Search Publications
A synthetic view on structure and evolution of the Milky Way
Reylé, C.; Robin, A. C.; Derrière, S. +1 more
Since the Hipparcos mission and recent large scale surveys in the optical and the near-infrared, new constraints have been obtained on the structure and evolution history of the Milky Way. The population synthesis approach is a useful tool to interpret such data sets and to test scenarios of evolution of the Galaxy. We present here new constraints…
Astrometric Calibration of the Sloan Digital Sky Survey
Hennessy, G. S.; Munn, Jeffrey A.; Ivezić, Željko +4 more
The astrometric calibration of the Sloan Digital Sky Survey is described. For point sources brighter than r~20, the astrometric accuracy is 45 mas rms per coordinate when reduced against the USNO CCD Astrograph Catalog and 75 mas rms when reduced against Tycho-2, with an additional 20-30 mas systematic error in both cases. The rms errors are domin…
The chemical compositions of Galactic disc F and G dwarfs
Lambert, David L.; Allende Prieto, Carlos; Reddy, Bacham E. +1 more
Photospheric abundances are presented for 27 elements from carbon to europium in 181 F and G dwarfs from a differential local thermodynamic equilibrium (LTE) analysis of high-resolution and high signal-to-noise ratio spectra. Stellar effective temperatures (Teff) were adopted from an infrared flux method calibration of Strömgren photome…
3D mapping of the dense interstellar gas around the Local Bubble
Crifo, F.; Lallement, R.; Welsh, B. Y. +2 more
We present intermediate results from a long-term program of mapping the neutral absorption characteristics of the local interstellar medium, motivated by the availability of accurate and consistent parallaxes from the Hipparcos satellite. Equivalent widths of the interstellar NaI D-line doublet at 5890 Å are presented for the lines-of-sight toward…
Distances and ages of NGC 6397, NGC 6752 and 47 Tuc
Grundahl, F.; Clementini, G.; Bragaglia, A. +4 more
New improved distances and absolute ages for the Galactic globular clusters NGC 6397, NGC 6752, and 47 Tuc are obtained using the Main Sequence Fitting Method. We derived accurate estimates of reddening and metal abundance for these three clusters using a strictly differential procedure, where the Johnson B-V and Strömgren b-y colours and UVES hig…
Abundances for metal-poor stars with accurate parallaxes. I. Basic data
Barbieri, M.; Claudi, R.; Carretta, E. +2 more
We present element-to-element abundance ratios measured from high dispersion spectra for 150 field subdwarfs and early subgiants with accurate Hipparcos parallaxes (errors <20%). For 50 stars new spectra were obtained with the UVES on Kueyen (VLT UT2), the McDonald 2.7 m telescope, and SARG at TNG. Additionally, literature equivalent widths wer…
A Planetary Companion to γ Cephei A
Cochran, William D.; Endl, Michael; Hatzes, Artie P. +5 more
We report on the detection of a planetary companion in orbit around the primary star of the binary system γ Cephei. High-precision radial velocity measurements using four independent data sets spanning the time interval 1981-2002 reveal long-lived residual radial velocity variations superposed on the binary orbit that are coherent in phase and amp…
Vertical distribution of Galactic disk stars. I. Kinematics and metallicity
Soubiran, C.; Siebert, A.; Bienaymé, O.
Nearly 400 Tycho-2 stars have been observed in a 720 square degree field in the direction of the North Galactic Pole with the high resolution echelle spectrograph ELODIE. Absolute magnitudes, effective temperatures, gravities and metallicities have been estimated, as well as distances and 3D velocities. Most of these stars are clump giants and spa…
Multiplicity among solar-type stars. III. Statistical properties of the F7-K binaries with periods up to 10 years
Arenou, F.; Udry, S.; Mayor, M. +1 more
Two CORAVEL radial velocity surveys - one among stars in the solar neighbourhood, the other in the Pleiades and in Praesepe - are merged to derive the statistical properties of main-sequence binaries with spectral types F7 to K and with periods up to 10 years. A sample of 89 spectroscopic orbits was finally obtained. Among them, 52 relate to a fre…
Investigation of 131 Herbig Ae/Be Candidate Stars
Alencar, S. H. P.; Corradi, W. J. B.; Guimarães, M. M. +5 more
We present a new catalog of 108 Herbig Ae/Be candidate stars identified in the Pico dos Dias Survey, together with 19 previously known candidates and four objects selected from the IRAS Faint Source Catalog. These 131 stars were observed with low- and/or medium-resolution spectroscopy, and we complement these data with high-resolution spectra of 3…