William I. Hartkopf

The Third US Naval Observatory CCD Astrograph Catalog (UCAC3)

The second US Naval Observatory (USNO) CCD Astrograph Catalog, UCAC2 was released in 2003 July. Positions and proper motions for 48,330,571 sources (mostly stars) are available on 3 CDs, supplemented with Two Micron All Sky Survey photometry for 99.5% of the sources. The catalog covers the sky area from -90° to +40° declination, going up to +52° in some areas; this completely supersedes the UCAC1 released in 2001. Current epoch positions are obtained from observations with the USNO 8 inch (0.2 m) Twin Astrograph equipped with a 4K CCD camera. The precision of the positions are 15–70 mas, depending on magnitude, with estimated systematic errors of 10 mas or below. Proper motions are derived by using over 140 ground- and space-based catalogs, including Hipparcos/Tycho and the AC2000.2, as well as yet unpublished remeasures of the AGK2 plates and scans from the NPM and SPM plates. Proper-motion errors are about 1–3 mas yr-1 for stars to 12th magnitude, and about 4–7 mas yr-1 for fainter stars to 16th magnitude. The observational data, astrometric reductions, results, and important information for the users of this catalog are presented.

The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog

The Washington Double Star Catalog (WDS), maintained by the US Naval Observatory, is the worlds principal database of astrometric double and multiple star information. The WDS contains positions (J2000), discoverer designations, epochs, position angles, separations, magnitudes, spectral types, proper motions, and, when available, Durchmusterung numbers and notes for the components of 84,486 systems based on 563,326 means. The current version, available on-line, is updated nightly. This catalog is one of four USNO double star catalogs to be included on a new CD-ROM. A brief summary and statistical analysis of the contents of the catalog are presented.

ICCD Speckle Observations of Binary Stars. XIX. An Astrometric/Spectroscopic Survey of O Stars

We present the results of a speckle interferometric survey made with the CHARA speckle camera and 4 m–class telescopes of Galactic O-type stars with V 59% have a visual or spectroscopic companion) but less so among field and especially runaway stars. There are many triple systems among the speckle binaries, and we discuss their possible role in the ejection of stars from clusters. The period distribution of the binaries is bimodal in log P, but we suggest that binaries with periods of years and decades may eventually be found to fill the gap. The mass ratio distribution of the visual binaries increases toward lower mass ratios, but low mass ratio companions are rare among close, spectroscopic binaries (probably because of the difficulty of spectroscopic detection rather than a real deficit). We present distributions of the eccentricity and longitude of periastron for spectroscopic binaries with elliptical orbits, and we find strong evidence of a bias in the longitude of periastron distribution (the Barr effect), which is probably caused by line distortions introduced by circumstellar gas.

First results from the chara array. II. A description of the instrument

The CHARA Array is a six 1 m telescope optical/IR interferometric array located on Mount Wilson, California, designed and built by the Center for High Angular Resolution Astronomy of Georgia State University. In this paper we describe the main elements of the Array hardware and software control systems, as well as the data reduction methods currently being used. Our plans for upgrades in the near future are also described.

The 2001 US Naval Observatory Double Star CD-ROM. II. The Fifth Catalog of Orbits of Visual Binary Stars

The Fifth Catalog of Orbits of Visual Binary Stars continues the series of compilations of visual binary star orbits published by Finsen, Worley, and Heintz from the 1930s to the 1980s. As of 2001 January 1, the new catalog includes 1465 orbits of 1430 systems. All orbits have been graded as in earlier catalogs, although the grading scheme has been modified to be more objective. Ephemerides are given for all orbits, as are plots including all associated data in the Washington Double Star 2001.0 database. A subset of orbits useful for scale calibration is also presented. This catalog is one of four USNO double star catalogs to be included on a new CD-ROM.

SPECKLE INTERFEROMETRY AT THE BLANCO AND SOAR TELESCOPES IN 2008 AND 2009

The results of speckle interferometric measurements of binary and multiple stars conducted in 2008 and 2009 at the Blanco and SOAR 4 m telescopes in Chile are presented. A total of 1898 measurements of 1189 resolved pairs or sub-systems and 394 observations of 285 un-resolved targets are listed. We resolved for the first time 48 new pairs, 21 of which are new sub-systems in close visual multiple stars. Typical internal measurement precision is 0.3 mas in both coordinates, typical companion detection capability is Δm ~ 4.2 at 015 separation. These data were obtained with a new electron-multiplication CCD camera; data processing is described in detail, including estimation of magnitude difference, observational errors, detection limits, and analysis of artifacts. We comment on some newly discovered pairs and objects of special interest.

ICCD speckle observations of binary stars. X - A further survey for duplicity among the bright stars

Speckle interferometric observations from the Canada-France-Hawaii 3.6 m and Cerro Tololo 4 m telescopes are reported for 1123 stars selected from the Yale Bright Star Catalogue in a continuing effort to detect new binaries among the bright stars. Thirty-two previously unresolved binaries have been detected, including companions to ξ UMa and 15 S Mon. Measures of 107 previously resolved systems, many of which resulted from earlier speckle observations, are also presented. No evidence of duplicity within a specific (m,Δm,ρ) window of detectability was found for 984 bright stars. These observations combined with two previously published surveys represent the inspection of 2088 stars, representing 23% of the members of the Bright Star Catalogue

The 2001 US Naval Observatory Double Star CD-ROM. III. The Third Catalog of Interferometric Measurements of Binary Stars

The Third Catalog of Interferometric Measurements of Binary Stars includes all published measures of binary and multiple star systems obtained by high-resolution techniques (speckle interferometry, photoelectric occultation timings, etc.), as well as negative examinations for duplicity, as of 2001 January 1. This catalog is one of four USNO double star catalogs to be included on a new CD-ROM. A brief summary and statistical analysis of the contents of the catalog are presented.

ICCD SPECKLE OBSERVATIONS OF BINARY STARS. XXIII. MEASUREMENTS DURING 1982¨1997 FROM SIX TELESCOPES, WITH 14 NEW ORBITS

We present 2017 observations of 1286 binary stars, observed by means of speckle interferometry using six telescopes over a 15 year period from 1982 April to 1997 June. These measurements constitute the 23d installment in CHARAs speckle program at 2 to 4 m class telescopes and include the second major collection of measurements from the Mount Wilson 100 inch (2.5 m) Hooker Telescope. Orbital elements are also presented for 14 systems, seven of which have had no previously published orbital analyses.

Binary Star Differential Photometry Using the Adaptive Optics System at Mount Wilson Observatory

We present photometric and astrometric results for 36 binary systems observed with the natural guide star adaptive optics system of the Mount Wilson Institute on the 100 inch (2.5 m) Hooker Telescope. The measurements consist of differential photometry in U, B, V, R, and I filters along with astrometry of the relative positions of system components. Magnitude differences were combined with absolute photometry found in the literature of the combined light for systems to obtain apparent magnitudes for the individual components at standard bandpasses, which in turn led to color determinations and spectral types. The combination of these results with Hipparcos parallax measurements yielded absolute magnitudes and allowed us to plot the components on an H-R diagram. To further examine the reliability and self-consistency of these data, we also estimated system masses from the spectral types.