Rotational velocities of A-type stars in the northern hemisphere. II. Measurement of v sin i
This work is the second part of the set of measurements of v sin i forA-type stars, begun by Royer et al. (\cite{Ror_02a}). Spectra of 249 B8to F2-type stars brighter than V=7 have been collected at Observatoirede Haute-Provence (OHP). Fourier transforms of several line profiles inthe range 4200-4600 Å are used to derive v sin i from thefrequency of the first zero. Statistical analysis of the sampleindicates that measurement error mainly depends on v sin i and thisrelative error of the rotational velocity is found to be about 5% onaverage. The systematic shift with respect to standard values fromSlettebak et al. (\cite{Slk_75}), previously found in the first paper,is here confirmed. Comparisons with data from the literature agree withour findings: v sin i values from Slettebak et al. are underestimatedand the relation between both scales follows a linear law ensuremath vsin inew = 1.03 v sin iold+7.7. Finally, thesedata are combined with those from the previous paper (Royer et al.\cite{Ror_02a}), together with the catalogue of Abt & Morrell(\cite{AbtMol95}). The resulting sample includes some 2150 stars withhomogenized rotational velocities. Based on observations made atObservatoire de Haute Provence (CNRS), France. Tables \ref{results} and\ref{merging} are only available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr (130.79.125.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/393/897
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On the HIPPARCOS photometry of chemically peculiar B, A, and F stars
The Hipparcos photometry of the Chemically Peculiar main sequence B, A,and F stars is examined for variability. Some non-magnetic CP stars,Mercury-Manganese and metallic-line stars, which according to canonicalwisdom should not be variable, may be variable and are identified forfurther study. Some potentially important magnetic CP stars are noted.Tables 1, 2, and 3 are available only in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
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The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1995ApJS...99..135A&db_key=AST
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The early F-type stars - Refined classification, confrontation with Stromgren photometry, and the effects of rotation
The classification for early F-type stars in the MK spectralclassification system presented by Gray and Garrison (1987) is refined.The effect of rotation on spectral classification and ubvy-betaphotometry of early F-type stars is examined. It is found that theclassical luminosity criterion, the 4417 A/4481 A ratio givesinconsistent results. It is shown that most of the stars in the DeltaDelphini class of metallic-line stars are either normal or areindistinguishable from proto-Am stars. It is suggested that thedesignation Delta Delphini should be dropped. The classifications arecompared with Stromgren photometry. The effects of rotation on thedelta-c1 index in the early-F field dwarfs is demonstrated.
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The early A type stars - Refined MK classification, confrontation with Stroemgren photometry, and the effects of rotation
The MK classification system for the early A-type stars is refined, anda parallel system of standards for the broad-lined stars is introduced.With this improved system, stars may be classified with significantlygreater precision than before. It is shown that spectral types in thissystem are not systematically affected by rotational line broadening. Atotal of 372 early A-type stars are classified, and a confrontation ofthese spectral types with Stroemgren photometry reveals a number ofsystematic photometric effects of rotation. In particular, high v sin istars are systematically redder than low v sin i stars of the samespectral type, and the beta index is weakened by rotation. It isconcluded that precise spectral classification in conjunction withStroemgren and H-beta photometry can potentially provide a valuablecheck and input to the theory of the atmospheres of rotating stars.
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An atlas of 12 rather subtle composite spectra
True composite spectra, at MK classification dispersion, have beenobtained from the components of close visual binaries. From an availableset of 46 composites, 12 are presented in photographic montages with thespectra of their component stars for comparison. These 12, ranging inspectral type from B2 to G5, illustrate mainly the less easilyrecognized composite spectra. An analysis of their peculiaritiesgenerates seven typical clues which can alert the classifier to thecomposite nature of a spectrum under examination.
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On the (B-V) colors of the bright stars
The possible causes of the dispersion of (B-V) colors of nearby stars inthe Bright Star Catalog are investigated. The distribution of (B-V)colors is presented for the entire range of spectral classes.Explanations for the dispersion in terms of a nonuniform distribution ofinterstellar absorbing material and a variability of metallicity areaddressed. A new statistical model for reddening by interstellar dustclouds is developed. It is concluded that extinction by nonuniforminterstellar matter is an important contribution to the reddening ofnearby stars, and that a part of the dispersion of (B-V) colors of Kand, possibly, M giants may be due to some unidentified variableproperty of those stars.
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A Note about the Comparison Between the Old and New Slettebak Systems of Axial Rotational Velocities
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1984RMxAA...9....9G&db_key=AST
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Close visual binaries. I - MK classifications
Each component of 170 close visual binaries has been classified with newprocedures for controlling contamination problems. These classificationsare presented and are shown to be on the MK system. Two sources of areascanner UBV photometry were compared in order to establish homogeneousphotometric as well as spectroscopic data. From a consideration ofsystematic errors in the V magnitude difference (Delta V) betweencomponents the photometry of Hurly and Warner (1983) is to be preferred.Absolute magnitudes for each binary are derived from Delta V via atested MK - M(v) map.
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The nature of the visual companions of AP and AM stars
The stars in 43 visual multiples with Ap or Am primaries have beenclassified, and the fraction of systems that have Ap or Am secondariesis counted. The numbers of Ap secondaries are too few to be informative,but an apparent excess of Am secondaries is found. That result isunderstandable in terms of the (published) moderate correlation inrotational velocities between components in visual multiples. But invarious open clusters, the variations in frequencies of Ap and Am starscan be explained probably as statistical fluctuations in small numbersof stars, indicating no tendency for abnormal stars to group togetherfor dimensions larger than those of visual multiples.
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Close visual binaries. III - Parameters and evolutionary status
New Yale isochrones, which have been tested for accuracy by Corbally(1984), provide the means to investigate interesting visual binaries,especially those whose classifications and photometry do not match well.Various parameters are deduced for those binaries which fitted theisochrones (e.g. ages, metal abundances, luminosities of peculiarstars); various solutions are systematically developed for those whichdid not fit; and a likely status of evolution is proposed (e.g.,duplicity of the components, premain-sequence, blue straggler,horizontal branch, optical pair, data inaccuracies). Evolution aroundthe helium flash and diffusion theory are briefly considered. Theseparameters and statuses provide a wealth of new stellar data andsuggestions for further investigation.
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Area Scanner Observations of Close Visual Double Stars - Part Two - Results for 153 Southern Stars
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1983MNRAS.202..761H&db_key=AST
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Photometric boxes in the four-color system
Photometric boxes derived from the latest four-color catalogue compiledby Hauck and Mermilliod (1980) containing uvby and H-beta observationsfor more than 15,000 stars are discussed. The construction andpopulation of stellar boxes, the distribution of boxes with spectraltype, the relations between a geneva box and a four-color box, and theuse of stellar boxes for photometric classification are considered. Itis concluded that the method of stellar boxes is a very useful tool inphotometric investigation.
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Standardization of stellar radial velocities in the presence of stellar rotation
Radial velocity standardization is reinvestigated, with emphasis on thepreviously neglected influence of stellar rotation, on the basis of 340spectrograms of 80 reference stars of spectral types B6-M0. Attention isgiven to the methods presently used to examine the influence of stellarrotation on the radial velocities obtained from individual lines and forthe selection of lines as free as possible from spectral type androtation dependence. This is done on the basis of observations of 68reference stars in the spectral type interval B6-F5, where the problemof rotation is most pronounced. In light of the accuracies achieved forstars of different rotations, a simple, rotation-independent criterionfor velocity variability is defined.
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Erratum - Discordances Between SAO and HD Numbers for Bright Stars
Not Available
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UBVRI photometry of 225 AM stars
UBVRI photometry of 225 Am stars taken from Mendoza's (1974) catalog ispresented. The results are compared with those obtained by Feinstein(1974) for 21 of the stars and with the values of Johnson et al. (1966).It is assumed that in the first approximation the (V-I) color index ofan unreddened Am star is equal to that of a normal main-sequence star; astandard main sequence is defined for A and early F stars, and thefive-color photometry is analyzed by means of plots of U-V vs. V-I, B-Vvs. V-I, and V-R vs. V-I. Mean color deficiencies of Am stars areexamined, and it is suggested that an unreddened star located below themain-sequence A0-F2 line in the (V-I, U-V) plane is a photometric Amstar. It is concluded that: (1) photometric Am stars have colordeficiencies (as a function of V-I) which, on the average, are 0.07 magin (U-V) color index and 0.025 mag in (B-V) color index; (2) Am starswith V-R less than 0.25 mag may also have a color deficiency of about0.01 mag; (3) Am stars with V-R greater than 0.3 mag may have a colorexcess of approximately 0.01 mag; and (4) Am stars with V-R between 0.25and 0.3 mag may have normal colors.
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Rotational velocities and spectral types for a sample of binary systems.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1975A&AS...19...91L&db_key=AST
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Multicolor photometry of metallic-line stars. III. A photometric catalogue
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1974RMxAA...1..175M&db_key=AST
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A finding list of stars of spectral type A7 and earlier in regions at high galactic latitudes. VI. Near South Galactic Pole.
Not Available
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Radial Velocities and Spectral Classification of A-Type Stars Near the South Galactic Pole
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1971PASP...83..643B&db_key=AST
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A finding list of early-type stars near the south galactic pole.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1971AJ.....76..338S&db_key=AST
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Line strengths for southern OB stars-II. Observations with moderate dispersion
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1969MNRAS.144...31B&db_key=AST
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Three-colour photometry of early-type stars near the galactic poles
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1963MNRAS.127...83W&db_key=AST
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Radial velocities of bright southern stars, III
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1963MNRAS.126...29B&db_key=AST
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Photovisual differences in magnitudes of 331 mainly southern double stars
Not Available
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INHABITED SKY
