|The Indo-US Library of Coudé Feed Stellar Spectra|
We have obtained spectra for 1273 stars using the 0.9 m coudéfeed telescope at Kitt Peak National Observatory. This telescope feedsthe coudé spectrograph of the 2.1 m telescope. The spectra havebeen obtained with the no. 5 camera of the coudé spectrograph anda Loral 3K×1K CCD. Two gratings have been used to provide spectralcoverage from 3460 to 9464 Å, at a resolution of ~1 Å FWHMand at an original dispersion of 0.44 Å pixel-1. For885 stars we have complete spectra over the entire 3460 to 9464 Åwavelength region (neglecting small gaps of less than 50 Å), andpartial spectral coverage for the remaining stars. The 1273 stars havebeen selected to provide broad coverage of the atmospheric parametersTeff, logg, and [Fe/H], as well as spectral type. The goal ofthe project is to provide a comprehensive library of stellar spectra foruse in the automated classification of stellar and galaxy spectra and ingalaxy population synthesis. In this paper we discuss thecharacteristics of the spectral library, viz., details of theobservations, data reduction procedures, and selection of stars. We alsopresent a few illustrations of the quality and information available inthe spectra. The first version of the complete spectral library is nowpublicly available from the National Optical Astronomy Observatory(NOAO) via ftp and http.
|Microstructure of the Local Interstellar Cloud and the Identification of the Hyades Cloud|
We analyze high-resolution UV spectra of the Mg II h and k lines for 18members of the Hyades to study inhomogeneity along these proximate linesof sight. The observations were taken by the Space Telescope ImagingSpectrograph (STIS) instrument on board the Hubble Space Telescope(HST). Three distinct velocity components are observed. All 18 lines ofsight show absorption by the Local Interstellar Cloud (LIC); 10 starsshow absorption by an additional cloud, which we name the Hyades Cloud;and one star exhibits a third absorption component. The LIC absorptionis observed at a lower radial velocity than predicted by the LICvelocity vector derived by Lallement & Bertin in 1992 and Lallementet al. in 1995[vpredicted(LIC)-vobserved(LIC)=2.9+/-0.7 kms-1], which may indicate a compression or deceleration at theleading edge of the LIC. We propose an extension of the Hyades Cloudboundary based on previous HST observations of other stars in thegeneral vicinity of the Hyades, as well as ground-based Ca IIobservations. We present our fits of the interstellar parameters foreach absorption component. The availability of 18 similar lines of sightprovides an excellent opportunity to study the inhomogeneity of thewarm, partially ionized local interstellar medium (LISM). We find thatthese structures are roughly homogeneous. The measured Mg II columndensities do not vary by more than a factor of 2 for angular separationsof <~8°, which at the outer edge of the LIC correspond tophysical separations of <~0.6 pc.
|Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition - Comments and statistics|
The Catalogue, available at the Centre de Données Stellaires deStrasbourg, consists of 13 573 records concerning the results obtainedfrom different methods for 7778 stars, reported in the literature. Thefollowing data are listed for each star: identifications, apparentmagnitude, spectral type, apparent diameter in arcsec, absolute radiusin solar units, method of determination, reference, remarks. Commentsand statistics obtained from CADARS are given. The Catalogue isavailable in electronic form at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (220.127.116.11) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcar?J/A+A/367/521
|The proper motions of fundamental stars. I. 1535 stars from the Basic FK5|
A direct combination of the positions given in the HIPPARCOS cataloguewith astrometric ground-based catalogues having epochs later than 1939allows us to obtain new proper motions for the 1535 stars of the BasicFK5. The results are presented as the catalogue Proper Motions ofFundamental Stars (PMFS), Part I. The median precision of the propermotions is 0.5 mas/year for mu alpha cos delta and 0.7mas/year for mu delta . The non-linear motions of thephotocentres of a few hundred astrometric binaries are separated intotheir linear and elliptic motions. Since the PMFS proper motions do notinclude the information given by the proper motions from othercatalogues (HIPPARCOS, FK5, FK6, etc.) this catalogue can be used as anindependent source of the proper motions of the fundamental stars.Catalogue (Table 3) is only available at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (18.104.22.168) or viahttp://cdsweb.u-strastg.fr/cgi-bin/qcat?J/A+A/365/222
|The intermediate-band approach to the surface-brightness method for Cepheid radii and distance determination|
The surface-brightness parameter Fν is calibrated in termsof the Strömgren intermediate-band colour b-y. The relationFν-(b-y)o valid for Cepheids is calibratedusing accurate near-infrared radii and distances for selected Cepheids.We have obtained uvby photometry for non-Cepheid giant and supergiantstars with known angular diameters and compared the slope and zero-pointof their Fν-(b-y)o relation with the Cepheidcalibration. We found that the two calibrations are significantlydifferent. The theoretical models lie in between the two calibrations.It is remarked that Fν-colour relations derived fromnon-Cepheids and involving blue colours (e.g. B-V or b-y) are notapplicable to Cepheids, while those involving redder colours (e.g. V-R,V-K or V-J) also produce good radii for Cepheids. Selected Cepheids ascalibrators lead to the accurate relationFν=3.898(+/-0.003)-0.378(+/-0.006)(b-y)o, whichallowed the calculation of radii and distances for a sample of 59Galactic Cepheids. The uncertainties in the zero-point and slope of theabove relation are similar to those obtained from near-infrared colours,and determine the accuracies in radii and distance calculations. Whileinfrared light and colour curves for Cepheids may be superior inprecision, the intermediate-band b-y colour allows the recovery of meanradii with an accuracy comparable to those obtained from the infraredsolutions. The derived distances are consistent within the uncertaintieswith those predicted by a widely accepted period-luminosityrelationship. Likewise, the resulting period-radius relation from theintermediate-band approach is in better agreement with infrared versionsthan with optical versions of this law. It is highlighted that theintermediate-band calibration of the surface-brightness method in thiswork is of comparable accuracy to the near-infrared calibrations. Thepresent results stress the virtues of uvby in determining the physicalparameters of supergiant stars of intermediate temperature.
|Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions|
The FK6 is a suitable combination of the results of the HIPPARCOSastrometry satellite with ground-based data, measured over more than twocenturies and summarized in the FK5. Part I of the FK6 (abbreviatedFK6(I)) contains 878 basic fundamental stars with direct solutions. Suchdirect solutions are appropriate for single stars or for objects whichcan be treated like single stars. From the 878 stars in Part I, we haveselected 340 objects as "astrometrically excellent stars", since theirinstantaneous proper motions and mean (time-averaged) ones do not differsignificantly. Hence most of the astrometrically excellent stars arewell-behaving "single-star candidates" with good astrometric data. Thesestars are most suited for high-precision astrometry. On the other hand,199 of the stars in Part I are Δμ binaries in the sense ofWielen et al. (1999). Many of them are newly discovered probablebinaries with no other hitherto known indication of binarity. The FK6gives, besides the classical "single-star mode" solutions (SI mode),other solutions which take into account the fact that hidden astrometricbinaries among "apparently single-stars" introduce sizable "cosmicerrors" into the quasi-instantaneously measured HIPPARCOS proper motionsand positions. The FK6 gives in addition to the SI mode the "long-termprediction (LTP) mode" and the "short-term prediction (STP) mode". TheseLTP and STP modes are on average the most precise solutions forapparently single stars, depending on the epoch difference with respectto the HIPPARCOS epoch of about 1991. The typical mean error of anFK6(I) proper motion in the single-star mode is 0.35 mas/year. This isabout a factor of two better than the typical HIPPARCOS errors for thesestars of 0.67 mas/year. In the long-term prediction mode, in whichcosmic errors are taken into account, the FK6(I) proper motions have atypical mean error of 0.50 mas/year, which is by a factor of more than 4better than the corresponding error for the HIPPARCOS values of 2.21mas/year (cosmic errors included).
|Distribution of gas, dust and the lambda 6613 Å DIB carrier in the Perseus OB2 association|
We present a study of the spatial distribution of the lambda 6613 ÄDIB carrier in the Perseus OB2 association based on high resolutionobservations toward lines of sight representing different interstellarenvironments. We determined that in the studied region, the lambda 6613Ä DIB carrier is concentrated in two distinct clouds withvelocities of 1.4 (+/- 0.4) and 12.0 (+/- 0.9) km s(-1) . We comparedthe lambda 6613 Ä DIB carrier's velocity with the Na I velocitydistribution derived from our survey measurements, as well as with CO,OH, H I and Ca Ii measurements from the literature. We conclude that thebehaviour of the carrier of the lambda 6613 Ä DIB follows theoverall expansion motion of the gas in the association. The DIB velocityis directly linked to that of Ca Ii and H I. The DIB total columndensity is proportional to the total column density of Ca Ii and H Imaking those atoms good tracers of the lambda 6613 Ä DIB carrier.Those new results support the assumption that the lambda 6613 Ä DIBwould arise from a gas phase molecule, possibly single-ionized(Sonnentrucker et al. 1997). We also conclude that the DIB carrier isdistributed in shell structures over the whole association. We finallyshow from the DIB velocity structure that the DIB carrier, gas and dustare well mixed toward the association but that the DIB shells have anangular extent twice larger than that of the dust. Based on observationswith OHP 1.52m Telescope and Aurelie spectrograph.
|53 Persei: a slowly pulsating B star|
A new investigation of the behaviour of the star 53Per was performed.New photometric observations allow to confirm two dominant periodsp_1=2.16d, p_2= 1.67d. A third one p_3= 3.64d is detected. These longperiod variations are present in our radial velocities data and in oldequivalent width data. The amplitude of the p_1 = 2.16d period increasesfrom 1977 to 1991, while the amplitude of the 1.67d period remainsconstant. Considering the observational characteristics of the starsince 1997, 53Per clearly belongs to the Slowly Pulsating B stars groupas defined by Waelkens (1991) and North & Paltani (1994).spectroscopic observations performed at the Haute Provence Observatory
|The Tokyo PMC catalog 90-93: Catalog of positions of 6649 stars observed in 1990 through 1993 with Tokyo photoelectric meridian circle|
The sixth annual catalog of the Tokyo Photoelectric Meridian Circle(PMC) is presented for 6649 stars which were observed at least two timesin January 1990 through March 1993. The mean positions of the starsobserved are given in the catalog at the corresponding mean epochs ofobservations of individual stars. The coordinates of the catalog arebased on the FK5 system, and referred to the equinox and equator ofJ2000.0. The mean local deviations of the observed positions from theFK5 catalog positions are constructed for the basic FK5 stars to comparewith those of the Tokyo PMC Catalog 89 and preliminary Hipparcos resultsof H30.
|Systematic Errors in the FK5 Catalog as Derived from CCD Observations in the Extragalactic Reference Frame.|
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1997AJ....114..850S&db_key=AST
|HR1328: a cool edge "Slowly Pulsating B Star".|
We report on the discovery of a photometric variability (in Stroemgren uand v filters) of HR 1328, a B8 main-sequence star. Two periods areeasily derived, of the order of 0.61d and 0.77d. From the position ofthis star in the HR diagram together with other pulsationalcharacteristics, HR 1328 can be classified as a Slowly Pulsating B star(SPB). Although these stars are found to oscillate in high-order g-modesthe relatively short pulsation periods of HR 1328 point towardslower-order g-modes in this case. Together with HD 123515, HR 1328extends and precises the observational cool edge of the SPB'sinstability strip.
|Vitesses radiales. Catalogue WEB: Wilson Evans Batten. Subtittle: Radial velocities: The Wilson-Evans-Batten catalogue.|
We give a common version of the two catalogues of Mean Radial Velocitiesby Wilson (1963) and Evans (1978) to which we have added the catalogueof spectroscopic binary systems (Batten et al. 1989). For each star,when possible, we give: 1) an acronym to enter SIMBAD (Set ofIdentifications Measurements and Bibliography for Astronomical Data) ofthe CDS (Centre de Donnees Astronomiques de Strasbourg). 2) the numberHIC of the HIPPARCOS catalogue (Turon 1992). 3) the CCDM number(Catalogue des Composantes des etoiles Doubles et Multiples) byDommanget & Nys (1994). For the cluster stars, a precise study hasbeen done, on the identificator numbers. Numerous remarks point out theproblems we have had to deal with.
|Search for coronene and ovalene cations in the diffuse interstellar medium.|
Recent studies suggest carbon-containing molecules as the bestcandidates for the carriers of the unidentified diffuse interstellarbands (DIBs), considering their abundance and ability to form stablebonds in interstellar space. The spectra of the naphthalene and pyrenecations in a neon matrix were recently reported, indicating a linkbetween these small polycyclic aromatic hydrocarbon (PAH) ions and somediffuse bands. We have searched for new DIBs in the near-infrared andaround 4592A in order to identify the coronene (C_24_H_12_) and ovalene(C_32_H_14_) cations in the diffuse medium. Due to their pericondensedstructure these molecules should be among the most stable PAHs in theinterstellar medium. The absorption spectra of both molecules wererecently measured in solid neon. We report on the search for the bandsat 9465/4592A and 9780A, and derive corresponding limits on the presenceof the coronene and ovalene cations in the diffuse interstellar medium.From these results, we discuss a possible selective destructionmechanism of PAHs through dication formation, and the role of PAHcompounds as possible DIB carriers.
|The local distribution of NA I interstellar gas|
We present high-resolution absorption measurements (lambda/Delta lambdaapproximately 75,000) of the interstellar Na I D lines at 5890 A toward80 southern hemisphere early-type stars located in the localinterstellar medium (LISM). Combining these results with other sodiummeasurements taken from the literature, we produce galactic maps of thedistribution of neutral sodium column density for a total of 293 starsgenerally lying within approximately 250 pc of the Sun. These mapsreveal the approximate shape of the mid-plane contours of the rarefiedregion of interstellar space termed the Local Bubble. Its shape is seenas highly asymmetric, with a radius ranging from 30 to 300 pc, and withan average radius of 60 pc. Similar plots of the Galactic mid-planedistribution of sources emitting extreme ultraviolet radiation show thatthey also trace out similar contours of the Local Bubble derived from NaI absorption measurements. We conclude that the Local Bubble absorptioninterface can be represented by a hydrogen column density,NuETA = 2 x 1019 cm-2, which explainsboth the local distribution of Na I absorption and the observed galacticdistribution of extreme ultraviolet sources. The derived mid-planecontours of the Bubble generally reproduce the large-scale featurescarved out in the interstellar medium by several nearby galactic shellstructures.
|A multisite UBV photometric campaign on 53 Persei in 1991 January|
New UBV observations of 53 Persei obtained during an internationalphotometric campaign in 1991 January are presented. Techniques ofobservation and data reduction employed at each of the fourparticipating observatories are described in detail, followed by adiscussion of the observational uncertainties and systematic errors. Theformal standard deviations determined from check-star measurements are0.011, 0.012, and 0.020 mag for V, B, and U, respectively. Multiplefrequency analysis shows that the light variations of 53 Persei duringthe campaign can be fitted very well by two sinusoids of frequencies0.462 and 0.603 cycles per day (c/d) which are practically identical tothose found by others from 1977-1983 photometric and spectroscopic data.The detection of the same frequencies in the data obtained more than 10yr apart has convincingly confirmed the stable multiperiodicity in 53Persei and extended the stability duration from 5.5 yr reported in anearlier investigation to about 13 yr. This pivotal result stronglysupports the nonradial pulsation as the physical cause responsible forlight and line-profile variations in this prototype star. Definitechanges have been detected in amplitudes and amplitude ratios of thelight variations. Since 1981, the amplitude ratio of the two modesmentioned above has increased from approximately 0.9 to greater than2.5. The single mode of 0.462 c/d has become the dominant component inthe two-mode pulsation of 53 Persei. The deviations of data from thetwo-frequency fits may imp ly the existence of additional frequencies.But we cannot prove this inference with present data.
|Stellar spectrophotometric standards. II|
|High-resolution CA II observations of the local interstellar medium|
High-resolution absorption measurements of the interstellar Ca II K lineobserved toward 46 early-type stars in the local ISM (LISM) arepresented. Ca II was detected in 36 of the 46 stars with 82 individualcloud components identified. Ca II was detected to most of the starscloser than 50 pc, except in the region of the Galactic quadrant l =180-270 degrees which also contains the empty line of sight to B CMa at220 pc. The mean local standard of rest velocity of the 82 Ca IIcomponents implies that the LISM clouds are associated with the motionof the solar neighborhood and not the sun. If the present data arecombined with other nearby Ca II component velocities taken from theliterature, then a cloud centered approximately at l = 90 deg, b = -40deg moving coherently with the local interstellar wind vector issupported at a significance level of 99 percent. The Ca II data havebeen combined with Na I data for the same stars to produce a N(NaI)/N(Ca II) ratio for each identified absorption feature. This ratioplotted against the local standard of rest velocities of the cloudsshows that the Routly-Spitzer effect exists down to +/- 10 km/s, whichsupports grain desorption/destruction models that are efficient atreturning calcium to the gas phase at these low velocities.
|Corrections to the right ascension to be applied to the apparent places of 1217 stars given in "The Chinese Astronomical Almanach" for the year 1984 to 1992.|
|Lambda Persei - an unusual B9 IV star|
Spectrograms of Lambda Per obtained at 30 A/mm in the red region showweak emission peaks in the core of the H-alpha absorption line. The V/Rfor the emission components changed from about 1.0 on October 28 1990 UTto less than 1.0 on October 29, 1990 UT. The midpoints of absorptionlines from He I, Si II, Fe II, and the midpoints of the H-alpha profilemeasured at residual intensities between 0.80 and 0.96 are shiftedslightly shortward of the wavelengths suggested by the catalog radialvelocities of Lambda Per and by the wavelength of the sharp centralabsorption core of H-alpha. It is plausible that the emission featuresoriginate in plage areas on the surface of Lambda Per, and that theaspect of the plages presented to the observer changes as the starrotates. Plages imply the presence of surface magnetic fields.
|Further high-resolution NA I observations of the local interstellar medium|
High-resolution absorption measurements of the interstellar Na I D linesat 5890 A observed toward 27 early-type stars in the local interstellarmedium (LISM) are presented. These results are combined with otherhigh-resolution sodium measurements to map the space distribution ofneutral sodium column density for some 118 stars out to less than 200pc. These measurements indicate an upper limit to the neutral sodiumcolumn density of log N(Na I) less than 10.0/sq cm can be inferred outto a distance of 50 pc in most directions in the LISM. Also, therarefield region of the Local Bubble may extend beyond 60 pc in at least35 percent of the directions sampled thus far. Evidence is shown for aubiquitous, comoving vector for neutral NaI gas clouds in the LISM whichis in a different direction to LISM vectors previously reported for moreionized local gas clouds. A comparison of the measured sodium columnswith those of interstellar Ca II for a sample of 12 stars within 95 pcresults in a ratio of Na I/Ca II less than 0.5 for most stars. Thisvalue implies that there could be warm, neutral gas with T of about12,500 K beyond 50 pc in the LISM.
|Physical data of the fundamental stars.|
|Third preliminary catalogue of stars observed with the photoelectric astrolabe of the Beijing Astronomical Observatory.|
|Angular diameter measurements of 24 giant and supergiant stars from the Mark III optical interferometer|
Preliminary stellar diameter measurements of 24 stars made with the MarkIII optical interferometer are reported. The stellar diameters reportedwere obtained using 12.0 and 8.3 m baselines with a center wavelength of674 nm and a bandwidth of 10 nm. The observed visibilities werenormalized using observations of nine stars of small angular diameter.The calibrated visibilities and best-fit uniform disk models for 24giant and supergiant stars of angular diameters 4 mas to 18 mas, withaccuracies of order 0.5 mas are presented.
|Stellar integrated fluxes in the wavelength range 380 NM - 900 NM derived from Johnson 13-colour photometry|
Petford et al. (1988) have reported measured integrated fluxes for 216stars with a wide spread of spectral type and luminosity, and mentionedthat a cubic-spline integration over the relevant Johnson 13-colormagnitudes, converted to fluxes using Johnson's calibration, is inexcellent agreement with those measurements. In this paper a list of thefluxes derived in this way, corrected for a small dependence on B-V, isgiven for all the 1215 stars in Johnson's 1975 catalog with completeentries.
|The equal-altitude method of quasi-absolute determination of star coordinates|
Absolute coordinate values are determined for 86 objects on the basis ofdata obtained with Mark II photoelectric astrolabe No. 2 at BeijingAstronomical Observatory during the period 1979-1984. The equal-altitudemethod employed in the computations is described in detail, and theresults are presented in tables. The mean accuracy of the positioncorrections is given as + or - 1.6 msec in right ascension and + or -0.019 arcsec in declination.
|Narrow band 1 micron-4 micron infrared photometry of 176 stars|
Observations of 176 stars have been obtained by filter photometry overthe 1-4 micron range at the Observatorio del Teide in Tenerife.Measurements for Jn, Kn, and Ln relative to Vega are presented, alongwith the probable errors of those stars observed for several nightsduring two of the three observing sessions. Mean quoted probable errorsof 0.018 m for Jn, 0.016 for Kn, and 0.027 for Ln are found.Transformations between the present narrow band magnitudes and Johnsonmagnitudes are presented.
|Stellar integrated fluxes for 216 stars in the wavelength range 380 nm-900 NM|
The paper reports measurements of the integrated fluxes over thewavelength range 380-900 nm for 216 stars using a reticon spectrometerin conjunction with the 1-m Kapteyn telescope of the Observatorio delRoque de los Muchachos. Methods are proposed for deriving visibleintegrated fluxes from 13-color photometry and UBVRI and BV photometry.Such fluxes are useful for deriving stellar effective temperatures andangular diameters.
|Two catalogues of FK4 right-ascension corrections and their application|
The results of observations conducted as part of the regular timeservice with transit instruments at the Borowiec and BratislavaObservatories were used to work out catalogs of right-ascensioncorrections of the FK4 stars, included in the observational programs.The characteristics of both catalogs are presented in the paper.Comparisons between the catalogs as well as their comparison with thecompilation catalog produced on the basis of observations performed withastrolabes are given. The results of applying these right-ascensioncorrections to the re-reduction of universal time are also presented.
|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.
|Narrow-band photometry of late-type stars. II|
This paper presents extensive narrow-band photometry in the Uppsalasystem supplementing earlier published mesurements so that data now areavailable for all late-type stars brighter than V = 6.05 and a number ofgalactic cluster members. Numerous UBV and BV measurements are alsopublished. The data are used to determine relations for the predictionof UBV intrinsic colors for late-type stars from the narrow-bandmeasurements. The main purpose of the data is to constitute the basisfor the determination of solar-neighborhood space densities of late-typestars, mainly giants of different kinds; these space densities will becombined with narrow-band data for fainter stars in the north Galacticpole region to yield the decrease of space density with distance fromthe galactic plane for many kinds of late-type stars.