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delta Scuti and related stars: Analysis of the R00 Catalogue
We present a comprehensive analysis of the properties of the pulsatingdelta Scuti and related variables based mainly on the content of therecently published catalogue by Rodríguez et al.(\cite{retal00a}, hereafter R00). In particular, the primaryobservational properties such as visual amplitude, period and visualmagnitude and the contributions from the Hipparcos, OGLE and MACHOlong-term monitoring projects are examined. The membership of thesevariables in open clusters and multiple systems is also analyzed, withspecial attention given to the delta Scuti pulsators situated ineclipsing binary systems. The location of the delta Scuti variables inthe H-R diagram is discussed on the basis of HIPPARCOS parallaxes anduvbybeta photometry. New borders of the classical instability arepresented. In particular, the properties of the delta Scuti pulsatorswith nonsolar surface abundances (SX Phe, lambda Boo, rho Pup, delta Deland classical Am stars subgroups) are examined. The Hipparcos parallaxesshow that the available photometric uvbybeta absolute magnitudecalibrations by Crawford can be applied correctly to delta Scutivariables rotating faster than v sin i ~ 100 km s{-1} withnormal spectra. It is shown that systematic deviations exist for thephotometrically determined absolute magnitudes, which correlate with vsin i and delta m1. The photometric calibrations are found tofit the lambda Boo stars, but should not be used for the group ofevolved metallic-line A stars. The related gamma Dor variables and thepre-main-sequence delta Scuti variables are also discussed. Finally, thevariables catalogued with periods longer than 0fd 25 are examined on astar-by-star basis in order to assign them to the proper delta Scuti, RRLyrae or gamma Dor class. A search for massive, long-period delta Scutistars similar to the triple-mode variable AC And is also carried out.
| A revised catalogue of delta Sct stars
An extensive and up-dated list of delta Sct stars is presented here.More than 500 papers, published during the last few years, have beenrevised and 341 new variables have been added to our last list, sixyears ago. This catalogue is intended to be a comprehensive review onthe observational characteristics of all the delta Sct stars known untilnow, including stars contained in earlier catalogues together with othernew discovered variables, covering information published until January2000. In summary, 636 variables, 1149 references and 182 individualnotes are presented in this new list. Tables 1 and 2 will be accessibleonly in electronic form at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| The 74th Special Name-list of Variable Stars
We present the Name-list introducing GCVS names for 3153 variable starsdiscovered by the Hipparcos mission.
| Interstellar Reddening in the Southern Hemisphere. II. Analysis of the uvby-Beta Observations
Photometric color excesses and distances plus heliocentric coordinatesare calculated for 3,762 southern A and early F stars. The presentresults, combined with those previously published for the northernhemisphere, complete the coverage of the spatial distribution ofinterstellar reddening in the entire solar neighborhood. The newreddening maps show that the interstellar matter within 300 pc of theSun forms a single very large cloud complex that is somewhatasymmetrical with respect to both the galactic center and the galacticplane. This complex is characterized by pronounced local irregularitiesin both density and spatial extent. The observations further indicatethat (1) the cloud complex is not associated with Gould's belt; (2)there exist large regions of the sky devoid of dust; (3) interstellarreddening is negligible at the galactic poles; (4) the role ofintercloud dust in the southern hemisphere; (5) the Sun is not locatedin a dust-free, spherically symmetric bubble as previously thought; and(6) the Sun is, however, located in an elongated dust-free region knownas the "local trough.". (SECTION: Interstellar Medium and Nebulae)
| Uvby-beta photometry of stars in the Michigan Spectral Catalogue. I - The Delta Del stars
uvby-beta photometry of 74 stars classified as Delta Del in Volume 1 ofthe Michigan Spectral Catalogue is presented. The photometry is inagreement with the spectral classification in that it indicates DeltaDel stars are metal-line-enhanced stars with equivalent-temperaturetypes of A9 + or - 2 subtypes. There is a discrepancy between theluminosity implied from the delta c1 index and the spectralclassification. It is argued that c1 is an inadequateluminosity indicator for some late A- to early F-type stars. Several ofthe Delta Del stars are known Delta Scuti pulsators, and some commentson the metallicism-pulsation relation are made.
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