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The Fourth US Naval Observatory CCD Astrograph Catalog (UCAC4)
Zacharias, N.; Finch, C. T.; Girard, T. M. +4 more
The fourth United States Naval Observatory (USNO) CCD Astrograph Catalog, UCAC4, was released in 2012 August (double-sided DVD and CDS data center Vizier catalog I/322). It is the final release in this series and contains over 113 million objects; over 105 million of them with proper motions (PMs). UCAC4 is an updated version of UCAC3 with about t…
Stellar Diameters and Temperatures. III. Main-sequence A, F, G, and K Stars: Additional High-precision Measurements and Empirical Relations
von Braun, Kaspar; White, Russel; Goldfinger, P. J. +13 more
Based on CHARA Array measurements, we present the angular diameters of 23 nearby, main-sequence stars, ranging from spectral types A7 to K0, 5 of which are exoplanet host stars. We derive linear radii, effective temperatures, and absolute luminosities of the stars using Hipparcos parallaxes and measured bolometric fluxes. The new data are combined…
Interferometric radii of bright Kepler stars with the CHARA Array: θ Cygni and 16 Cygni A and B
Stello, D.; White, T. R.; Baron, F. +18 more
We present the results of long-baseline optical interferometry observations using the Precision Astronomical Visual Observations (PAVO) beam combiner at the Center for High Angular Resolution Astronomy (CHARA) Array to measure the angular sizes of three bright Kepler stars: θ Cygni, and both components of the binary system 16 Cygni. Supporting inf…
Distance and Kinematics of the TW Hydrae Association from Parallaxes
Weinberger, Alycia J.; Anglada-Escudé, Guillem; Boss, Alan P.
From common proper motion and signatures of youth, researchers have identified about 30 members of a putative TW Hydrae Association. Only four of these had parallactic distances from Hipparcos. We have measured parallaxes and proper motions for 14 primary members. We combine these with literature values of radial velocities to show that the Galact…
HD 140283: A Star in the Solar Neighborhood that Formed Shortly after the Big Bang
Schaefer, Gail H.; Nelan, Edmund P.; Bond, Howard E. +2 more
HD 140283 is an extremely metal-deficient and high-velocity subgiant in the solar neighborhood, having a location in the Hertzsprung-Russell diagram where absolute magnitude is most sensitive to stellar age. Because it is bright, nearby, unreddened, and has a well-determined chemical composition, this star avoids most of the issues involved in age…
The bright end of the exo-Zodi luminosity function: disc evolution and implications for exo-Earth detectability
Wyatt, M. C.; Kennedy, G. M.
We present the first characterisation of the 12 µm warm dust (`exo-Zodi') luminosity function around Sun-like stars, focusing on the dustiest systems that can be identified by the WISE mission. We use the sample of main-sequence stars observed by Hipparcos within 150 pc as an unbiased sample, and report the detection of six new warm dust can…
Ca II H+K fluxes from S-indices of large samples: a reliable and consistent conversion based on PHOENIX model atmospheres
Schmitt, J. H. M. M.; Schröder, K. -P.; Mittag, M.
Context. Historic stellar activity data based on chromospheric line emission using O.C. Wilson's S-index reach back to the 1960ies and represent a very valuable data resource both in terms of quantity and time-coverage. However, these data are not flux-calibrated and are therefore difficult to compare with modern spectroscopy and to relate to quan…
Baade-Wesselink distances to Galactic and Magellanic Cloud Cepheids and the effect of metallicity
Groenewegen, M. A. T.
Context. The metallicity dependence of the Cepheid period-luminosity (PL) relation is of importance in establishing the extragalactic distance scale.
Aims: The aim of this paper is to investigate the metallicity dependence of the PL relation in V and K, based on a sample of 128 Galactic, 36 Large Magellanic Cloud (LMC), and 6 Small Magellanic…
The CORALIE survey for southern extrasolar planets. XVII. New and updated long period and massive planets
Alonso, R.; Queloz, D.; Sahlmann, J. +24 more
Context. Since 1998, a planet-search program around main sequence stars within 50 pc in the southern hemisphere has been carried out with the CORALIE echelle spectrograph at La Silla Observatory.
Aims: With an observing time span of more than 14 years, the CORALIE survey is now able to unveil Jovian planets on Jupiter's period domain. This gr…
Space Velocities of Southern Globular Clusters. VII. NGC 6397, NGC 6626 (M28), and NGC 6656 (M22)
Casetti-Dinescu, Dana I.; Girard, Terrence M.; van Altena, William F. +3 more
We have measured the absolute proper motions of globular clusters NGC 6397, NGC 6626 (M22), and NGC 6656 (M28) as part of our ongoing Southern Proper-Motion Program. The reference system is the ICRS via Hipparcos stars for these three low-Galactic-latitude clusters. Formal errors range between ~0.3 and 0.7 mas yr-1. Notable is the resul…