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The Radial Velocity Experiment (RAVE): First Data Release
Gilmore, G.; Freeman, K. C.; Evans, N. W. +51 more
We present the first data release of the Radial Velocity Experiment (RAVE), an ambitious spectroscopic survey to measure radial velocities and stellar atmosphere parameters (temperature, metallicity, and surface gravity) of up to one million stars using the Six Degree Field multiobject spectrograph on the 1.2 m UK Schmidt Telescope of the Anglo-Au…
Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 pc-The Southern Sample
Gray, R. O.; Corbally, C. J.; Garrison, R. F. +5 more
We are obtaining spectra, spectral types, and basic physical parameters for the nearly 3600 dwarf and giant stars earlier than M0 in the Hipparcos catalog within 40 pc of the Sun. Here we report on results for 1676 stars in the southern hemisphere observed at Cerro Tololo Inter-American Observatory and Steward Observatory. These results include ne…
A Recalibration of Optical Photometry: Tycho-2, Strömgren, and Johnson Systems
Maíz Apellániz, J.
I use high-quality Hubble Space Telescope (HST) spectrophotometry to analyze the calibration of three popular optical photometry systems: Tycho-2 BT and VT, Strömgren uvby, and Johnson UBV. For Tycho-2, I revisit the analysis of an earlier paper to include the new recalibration of grating/aperture corrections, vignetting, and charge transfer ineff…
Dynamical Evolution of the TW Hydrae Association
Ortega, V. G.; de la Reza, R.; Jilinski, E.
Using Galactic dynamics we have determined the age of the low-mass post-T Tauri stars in the TW Hya Association (TWA). To do so we applied the method of Ortega and coworkers to five stars of the association with Hipparcos-measured distances (TWA 1, TWA 4, TWA 9, TWA 11, and TWA 19). The method is based on the calculation of the past three-dimensio…
Precision Kinematics and Related Parameters of the α Persei Open Cluster
Makarov, Valeri V.
A kinematical study of the nearby open cluster α Persei is presented based on the astrometric proper motions and positions in the Tycho-2 catalog and Second USNO CCD Astrographic Catalog (UCAC2). Using the astrometric data and photometry from the Tycho-2 and ground-based catalogs, 139 probable members of the cluster are selected, 18 of them new. B…
OB Stars in the Solar Neighborhood. II. Kinematics
Alfaro, E. J.; Cabrera-Caño, J.; Elias, F.
Using the spatial classification method and the structural parameters estimated for the Gould Belt (GB) and the local Galactic disk (LGD) from a previous paper, we have evaluated spatial membership probabilities for a sample of O and B stars from the Hipparcos catalog (Perryman and coworkers) with available proper motions and radial velocity data.…
The Hyades Binary θ2 Tauri: Confronting Evolutionary Models with Optical Interferometry
Hajian, Arsen R.; Hummel, C. A.; Johnston, K. J. +5 more
We determine the masses and magnitude difference of the components of the Hyades spectroscopic binary θ2 Tauri. We find that both components appear to be less massive and/or brighter than predicted from some recent evolutionary models. The rapid rotation and unknown rotational inclination of both components introduce uncertainty in thei…
The Astrometric-Spectroscopic Binary System HIP 50796: An Overmassive Companion
Torres, Guillermo
We report spectroscopic observations of the star HIP 50796, previously considered (but later rejected) as a candidate member of the TW Hya association. Our measurements reveal it to be a single-lined binary with an orbital period of 570 days and an eccentricity of e=0.61. The astrometric signature of this orbit was previously detected by Hipparcos…
CCD Speckle Observations of Binary Stars from the Southern Hemisphere. IV. Measures during 2001
Horch, Elliott P.; Franz, Otto G.; Baptista, Brian J. +1 more
We present 549 observations of 181 primarily southern binary stars. Of these, 32 are high-quality nondetections, meaning that, if binary, the system had a separation below the diffraction limit at the time of the observation, and relative astrometry is presented for the remaining 517 observations. In addition, a magnitude difference measure is rep…
Dynamical Masses of the Components in o Andromedae
Cvetković, Z.; Olević, D.
It has been shown in earlier papers that o And is a quadruple star. Based on spectroscopic observations, Hill and coworkers calculated the orbital elements for a binary, assigning it to the B component. We have calculated the orbital elements for the subsystems Aa-B and Aa using speckle interferometry measurements. The individual masses of the o A…