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Pulkovo compilation of radial velocities for 35495 stars in a common system.
Not Available
| Speckle Interferometry at the US Naval Observatory. V.
The results of 1544 speckle interferometric observations of 637 binarystars, ranging in separation from 0.25" to 5.25", are tabulated. Theseobservations were obtained using the 66 cm refractor at the US NavalObservatory in Washington, DC, with an intensified CCD detector. This isthe fifth in a series of papers presenting measures obtained with thissystem and covers the period 1998 January 1 through December 31. Randomerrors for all measures are estimated to be 17.6 mas in separation and0.55d/ρ in position angle, where ρ is the separation inarcseconds.
| Two-colour photometry for 9473 components of close Hipparcos double and multiple stars
Using observations obtained with the Tycho instrument of the ESAHipparcos satellite, a two-colour photometry is produced for componentsof more than 7 000 Hipparcos double and multiple stars with angularseparations 0.1 to 2.5 arcsec. We publish 9473 components of 5173systems with separations above 0.3 arcsec. The majority of them did nothave Tycho photometry in the Hipparcos catalogue. The magnitudes arederived in the Tycho B_T and V_T passbands, similar to the Johnsonpassbands. Photometrically resolved components of the binaries withstatistically significant trigonometric parallaxes can be put on an HRdiagram, the majority of them for the first time. Based on observationsmade with the ESA Hipparcos satellite.
| The Vienna-KPNO search for Doppler-imaging candidate stars. I. A catalog of stellar-activity indicators for 1058 late-type Hipparcos stars
We present the results from a spectroscopic Ca ii H&K survey of 1058late-type stars selected from a color-limited subsample of the Hipparcoscatalog. Out of these 1058 stars, 371 stars were found to showsignificant H&K emission, most of them previously unknown; 23% withstrong emission, 36% with moderate emission, and 41% with weak emission.These spectra are used to determine absolute H&K emission-linefluxes, radial velocities, and equivalent widths of theluminosity-sensitive Sr ii line at 4077 Ä. Red-wavelengthspectroscopic and Strömgren y photometric follow-up observations ofthe 371 stars with H&K emission are used to additionally determinethe absolute Hα -core flux, the lithium abundance from the Li i6708 Å equivalent width, the rotational velocity vsin i, theradial velocity, and the light variations and its periodicity. Thelatter is interpreted as the stellar rotation period due to aninhomogeneous surface brightness distribution. 156 stars were found withphotometric periods between 0.29 and 64 days, 11 additional systemsshowed quasi-periodic variations possibly in excess of ~50 days. Further54 stars had variations but no unique period was found, and four starswere essentially constant. Altogether, 170 new variable stars werediscovered. Additionally, we found 17 new SB1 (plus 16 new candidates)and 19 new SB2 systems, as well as one definite and two possible new SB3systems. Finally, we present a list of 21 stars that we think are mostsuitable candidates for a detailed study with the Doppler-imagingtechnique. Tables A1--A3 are only available in electronic form at theCDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| Speckle Interferometry at the US Naval Observatory. IV.
The results of 1314 speckle interferometric observations of 625 binarystars, ranging in separation from 0.2" to 5.2" with a limiting secondarymagnitude of V=11, are tabulated. These observations were obtained usingthe 66 cm refractor at the US Naval Observatory in Washington, DC, withan intensified CCD detector. This is the fourth in a series of paperspresenting measures obtained with this equipment and covers the period1997 January 1 through December 31. Random errors for all measures areestimated to be 18 mas in separation and 0.57d/rho in position angle,where rho is the separation in arcseconds.
| Speckle Interferometry at the US Naval Observatory. III.
Position angles and separations resulting from 2578 speckleinterferometric observations of 590 binary stars are tabulated. This isthe third in a series of papers presenting measures obtained using the66 cm refractor at the US Naval Observatory in Washington, DC, andcovers the period from 1995 June through 1996 December. Program starsrange in separation from 0.2" to 4.3", with a limiting magnitude ofV=11. Random errors are estimated to be 17.0 mas in separation and0.56d/rho in position angle, where rho is the separation in arcseconds.These are the first results acquired using an improved intensified CCDdetector. The new detector, in concert with an intensity-filteringtechnique applied in software, has permitted a 1 mag increase in dynamicrange, to 3.5 mag, for pairs separated by about 2". The instrumentationand calibration are briefly described, with an emphasis on thecharacteristics of the new detector. The software filter used toincrease the dynamic range is also described.
| Ultraviolet and Optical Studies of Binaries with Luminous Cool Primaries and Hot Companions. V. The Entire IUE Sample
We have obtained or retrieved IUE spectra for over 100 middle- andlate-type giant and supergiant stars whose spectra indicate the presenceof a hot component earlier than type F2. The hot companions areclassified accurately by temperature class from their far-UV spectra.The interstellar extinction of each system and the relative luminositiesof the components are derived from analysis of the UV and opticalfluxes, using a grid of UV intrinsic colors for hot dwarfs. We find thatthere is fair agreement in general between current UV spectralclassification and ground-based hot component types, in spite of thedifficulties of assigning the latter. There are a few cases in which thecool component optical classifications disagree considerably with thetemperature classes inferred from our analysis of UV and opticalphotometry. The extinction parameter agrees moderately well with otherdeterminations of B-V color excess. Many systems are worthy of furtherstudy especially to establish their spectroscopic orbits. Further workis planned to estimate luminosities of the cool components from the dataherein; in many cases, these luminosities' accuracies should becomparable to or exceed those of the Hipparcos parallaxes.
| New peculiar stars identified on objective-prism plates
Tables are presented of 90 peculiar stars revealed on more than oneobjective-prism plate and 61 suspected peculiar stars based on a singlespectrum. The set of 90 peculiar stars includes 48 Ap, 32 Am, and 10stars with composite spectra. The stars were identified as peculiarstars during spectral classification in the regions of the OBassociations Cyg OB4, Cep-Lac OB1, and Cas OB9. The spectralcharacteristics of the different types of peculiar stars are discussed.
| Miscellaneous spectroscopic notes
Results of slit-spectrograph observations are reported for approximately260 stars. The data presented range from recognition of many new Ap, Am,and other unusual stars to H-alpha observations of early-typesupergiants and Be stars. The material discussed was obtained over thepast 40 years at a number of U.S. observatories and at the DominionAstrophysical Observatory in Victoria, B.C.
| IRAS maps for a region of sky containing nearby high-velocity gas, identified from IUE spectra
Detailed IRAS contour maps in the 60 and 100-micron wavebands arepresented for a small region of sky towards which 'high-velocity gascomponents' (HVC) have been clearly identified in spectra of backgroundstars obtained with the IUE satellite. There is a coincidence indirection on the sky between the strongest regions of absorptionproduced by HVC gas and compact regions of brightest IR emission.However, there is no clear evidence at present for identifying the HVCdirectly with the IR emission due to insufficient spatial informationalong the lines-of-sight examined. A comparison of H I column densitiesobtained from both the 100-micron emission and color excess dataindicates that dust emission, rather than atomic line emission, is thedominant contribution to the IRAS observations in the sightlinesconsidered.
| Local intersteller medium
Radio, IR, optical, UV, and X-ray observations of the local interstellarmedium (LISM) are reviewed, confirming the previous suggestion that thesun is located near an edge of a giant cavern with a radius of about 180pc whose center coincides with the Sco-Cen associated center. It issuggested that the bright spots of soft X-rays observed near thegalactic poles are produced by an interaction of stellar winds with theouter edge of the local cloud near the ends of Tinbergen's (1982) 'patchof polarization'. Results indicate that the main source of ionization ofextended H II regions of low density in the LISM is the Lyman continuumradiation from Sco-Cen stars.
| UBV photometry of stars whose positions are accurately known. II
The present report on the UBV observations of stars with favorableastrometric history gives attention to stars of the BD zones lyingbetween 50 and 54 deg. These observations and their reductions wereperformed from August 1983 to August 1984, as described by Oja (1984).Results are presented as tables for both the standard stars and theprogram stars. Comparisons are conducted between the present Vmagnitudes and those of the NPZT (1982) and AGK3R (1978) catalogs.
| On the distribution of interstellar matter around the sun
Available data on interstellar line or EUV continuum absorptionattributable to the local (r equal to or less than 100 pc) interstellarmedium are presented and analyzed as a whole for clues leading to adeeper understanding of the spatial distribution and physical propertiesof this material. By using these data in conjunction with upper limitsprovided by polarization and color excess surveys and relatingeverything to the neutral-hydrogen column density, it is shown that thedata are consistent with a simple model that assumes the relativelypervasive presence of a tenuous (nH = 0.07 per cu cm), possibly warm (T= 1,000-10,000 K) gas extending uniformly out to considerable distancesfrom the sun in most directions. The only region manifestly clear ofthis material lies in the 200 deg to 270 deg galactic longitude range inboth high and low latitudes. Strong density discontinuities are clearlyobservable at r approximately 100-150 pc in the general directions ofthe Sco-Cen and Per associations and a weaker discontinuity much closerto the sun running along a ridge oriented parallel to the lineconnecting their centers. Beyond these fronts, the space density ofinterstellar matter must fall to very low values that extend out toseveral hundred parsecs or so from the sun. These results are notincompatible with H I, 21-cm, and soft X-ray all-sky surveys. Theimplication of these findings for the theory of the interstellar mediumand EUV visibility is briefly discussed.
| New peculiar stars.
Not Available
| Identification of AM and AP Stars from Low-Dispersion Objective-Prism Spectra
Not Available
| Stellar Spectra in Milky way REGIONS.III.A Region in Cepheus-Lacerta
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1955ApJS....2...75M&db_key=AST
| A List of Newly Discovered Peculiar Objects.
Not Available
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משמש של הקבוצה הבאה
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תצפית ומידע אסטרומטרי
| קבוצת-כוכבים: | לטאה |
| התרוממות ימנית: | 22h20m35.23s |
| סירוב: | +53°48'53.8" |
| גודל גלוי: | 8.682 |
| מרחק: | 1492.537 פארסק |
| תנועה נכונה: | -7.7 |
| תנועה נכונה: | -3.5 |
| B-T magnitude: | 10.292 |
| V-T magnitude: | 8.815 |
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