Pulkovo compilation of radial velocities for 35495 stars in a common system.
Not Available
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Automated Classification of 2000 Bright IRAS Sources
An artificial neural network (ANN) scheme has been employed that uses asupervised back-propagation algorithm to classify 2000 bright sourcesfrom the Calgary database of Infrared Astronomical Satellite (IRAS)spectra in the region 8-23 μm. The database has been classified into17 predefined classes based on the spectral morphology. We have beenable to classify over 80% of the sources correctly in the firstinstance. The speed and robustness of the scheme will allow us toclassify the whole of the Low Resolution Spectrometer database,containing more than 50,000 sources, in the near future.
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Hipparcos red stars in the HpV_T2 and V I_C systems
For Hipparcos M, S, and C spectral type stars, we provide calibratedinstantaneous (epoch) Cousins V - I color indices using newly derivedHpV_T2 photometry. Three new sets of ground-based Cousins V I data havebeen obtained for more than 170 carbon and red M giants. These datasetsin combination with the published sources of V I photometry served toobtain the calibration curves linking Hipparcos/Tycho Hp-V_T2 with theCousins V - I index. In total, 321 carbon stars and 4464 M- and S-typestars have new V - I indices. The standard error of the mean V - I isabout 0.1 mag or better down to Hp~9 although it deteriorates rapidly atfainter magnitudes. These V - I indices can be used to verify thepublished Hipparcos V - I color indices. Thus, we have identified ahandful of new cases where, instead of the real target, a random fieldstar has been observed. A considerable fraction of the DMSA/C and DMSA/Vsolutions for red stars appear not to be warranted. Most likely suchspurious solutions may originate from usage of a heavily biased color inthe astrometric processing.Based on observations from the Hipparcos astrometric satellite operatedby the European Space Agency (ESA 1997).}\fnmsep\thanks{Table 7 is onlyavailable in electronic form at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/397/997
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New periodic variables from the Hipparcos epoch photometry
Two selection statistics are used to extract new candidate periodicvariables from the epoch photometry of the Hipparcos catalogue. Theprimary selection criterion is a signal-to-noise ratio. The dependenceof this statistic on the number of observations is calibrated usingabout 30000 randomly permuted Hipparcos data sets. A significance levelof 0.1 per cent is used to extract a first batch of candidate variables.The second criterion requires that the optimal frequency be unaffectedif the data are de-trended by low-order polynomials. We find 2675 newcandidate periodic variables, of which the majority (2082) are from theHipparcos`unsolved' variables. Potential problems with theinterpretation of the data (e.g. aliasing) are discussed.
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Dynamical masses of young star clusters in NGC 4038/4039
In order to estimate the masses of the compact, young star clusters inthe merging galaxy pair, NGC 4038/4039 (``the Antennae''), we haveobtained medium and high resolution spectroscopy using ISAAC on VLT-UT1and UVES on VLT-UT2 of five such clusters. The velocity dispersions wereestimated using the stellar absorption features of CO at 2.29 mu m andmetal absorption lines at around 8500 Å, including lines of theCalcium Triplet. The size scales and light profiles were measured fromHST images. From these data and assuming Virial equilibrium, weestimated the masses of five clusters. The resulting masses range from6.5 x 105 to 4.7 x 106 Msun. Thesemasses are large, a factor of a few to more than 10 larger than thetypical mass of a globular cluster in the Milky Way. The mass-to-lightratios for these clusters in the V- and K-bands in comparison withstellar synthesis models suggest that to first order the IMF slopes areapproximately consistent with Salpeter for a mass range of 0.1 to 100Msun. However, the clusters show a significant range ofpossible IMF slopes or lower mass cut-offs and that these variations maycorrelate with the interstellar environment of the cluster. Comparisonwith the results of Fokker-Planck simulations of compact clusters withproperties similar to the clusters studied here suggest that they arelikely to be long-lived and may lose a substantial fraction of theirtotal mass. This mass loss would make the star clusters obtain masseswhich are comparable to the typical mass of a globular cluster. Based onobservations collected at the European Southern Observatory, Chile.
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Long period variable stars: galactic populations and infrared luminosity calibrations
In this paper HIPPARCOS astrometric and kinematic data are used tocalibrate both infrared luminosities and kinematical parameters of LongPeriod Variable stars (LPVs). Individual absolute K and IRAS 12 and 25luminosities of 800 LPVs are determined and made available in electronicform. The estimated mean kinematics is analyzed in terms of galacticpopulations. LPVs are found to belong to galactic populations rangingfrom the thin disk to the extended disk. An age range and a lower limitof the initial mass is given for stars of each population. A differenceof 1.3 mag in K for the upper limit of the Asymptotic Giant Branch isfound between the disk and old disk galactic populations, confirming itsdependence on the mass in the main sequence. LPVs with a thin envelopeare distinguished using the estimated mean IRAS luminosities. The levelof attraction (in the classification sense) of each group for the usualclassifying parameters of LPVs (variability and spectral types) isexamined. Table only available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/374/968 or via ASTRIDdatabase (http://astrid.graal.univ-montp2.fr).
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The 74th Special Name-list of Variable Stars
We present the Name-list introducing GCVS names for 3153 variable starsdiscovered by the Hipparcos mission.
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The luminosity index for M stars and the distance to the LMC.
Not Available
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Classification and Identification of IRAS Sources with Low-Resolution Spectra
IRAS low-resolution spectra were extracted for 11,224 IRAS sources.These spectra were classified into astrophysical classes, based on thepresence of emission and absorption features and on the shape of thecontinuum. Counterparts of these IRAS sources in existing optical andinfrared catalogs are identified, and their optical spectral types arelisted if they are known. The correlations between thephotospheric/optical and circumstellar/infrared classification arediscussed.
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Quantitative spectral classification of galactic disc K-M stars from spectrophotometric measurements
New spectral observations for 47 southern galactic red supergiantsobtained with the new RUBIKON spectrophotometer (developed at theAstronomisches Institut der Ruhr-Universitat Bochum) at the Bochum 61-cmtelescope on La Silla are presented. The spectra range from 4800 to 7700A and their resolution is 10 A. The mean error of absolute fluxes is0.028 mag and that of relative fluxes 0.021 mag. The spectra will beavailable at the Strasbourg Stellar Database (CDS). Together with datataken from recently published spectral catalogues, the new observationshave been used to define spectral indices as measures of the strengthsof the following features: Fe i+TiOalpha_1, Mgb+TiOalpha_0,NaD+TiOgamma'_1, TiOgamma'_0 and TiOgamma_1 systems. The indices havebeen checked against errors introduced by reductions, interstellarreddening and different resolutions of different spectral catalogues,and have been found to be very insensitive to all these effects.Therefore, different catalogues may be combined without any loss ofaccuracy and homogeneity. The mean error of a single index has beenfound to be 0.011 mag. For stars from K4 to M7, a strong temperaturedependence is found for all indices. For the Fe i+TiO and especially theMgb+TiO features, a strong dependence on luminosity has also beenobserved. These indices therefore have been combined to form aluminosity index, while the others together form a spectral index. Thecombined indices have been calibrated in terms of MK data using thestepwise linear regression technique, and may be used for quantitativetwo- dimensional spectral classification of late K- and M-type stars.The mean error of the classification is 0.6 of spectral subtype and 0.8of luminosity class, which is much higher than would be expected fromthe uncertainty of the indices alone (which, e.g., for an M4 giantcorrespond to an uncertainty of 0.1 of spectral subtype and 0.3 ofluminosity class). This may be explained by the uncertainty of theoriginal MK classifications and the variability of some programme stars.
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1612 MHz OH survey of IRAS point sources. I - Observations made at Dwingeloo, Effelsberg and Parkes
The data from a large sky survey are presented including a northernpilot study and a detailed southern study in which detections are biasedtoward the most evolved sources and distant sources. Both areinvestigated at the 1612-MHz transition of OH to take advantage of thestrongest line for AGB stars with optically thick dust shells. The IRASsources are chosen by considering their IR colors related to fluxes at12, 25, and 60 microns. Observations are reported for 2703 IRAS pointsources at the 1612-MHz transition, and 738 OH/IR stars are detected.The survey identifies 597 of the sources as previously unidentified, and95 percent of the OH profiles observed have twin-peak masercharacteristics which are related to emission from expandingcircumstellar shells. The other 5 percent of the sources are concludedto be transition objects between OH/IR stars and planetary nebulae.
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Valinhos 2.2 micron survey of the southern galactic plane. II - Near-IR photometry, IRAS identifications and nature of the sources
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1987A&AS...71...39E&db_key=AST
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IRAS catalogues and atlases - Atlas of low-resolution spectra
Plots of all 5425 spectra in the IRAS catalogue of low-resolutionspectra are presented. The catalogue contains the average spectra ofmost IRAS poiont sources with 12 micron flux densities above 10 Jy.
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M supergiants in the Milky Way and the Magellanic Clouds Colors, spectral types, and luminosities
The differences in metal abundances between the Milky Way, LargeMagellanic Cloud (LMC), and Small Magellanic Cloud (SMC) affect most ofthe observable properties of the M supergiants in these galaxies; thosein the SMC (which has the lowest metal abundance) have the earliest meanspectral type, while those of the Milky Way exhibit the latest meanspectral type. This is presently interpreted as a combination of twoeffects of differing metal abundance on the supergiant atmospheres:first, lower abundance stars of a given effective temperature haveearlier MK spectral types due to reduced TiO abundance; second, theHayashi track is shifted to hotter effective temperature at reducedmetal abundance, thereby shifting the mean spectral type still earlier.The fact that the 10-micron excess decreases linearly with metalabundance suggests that mass loss rates are roughly the same for starsin all three galaxies, with the dust-to-gas ratio proportional to metalabundance.
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Photoelectric two-dimensional spectral classification of M supergiants
A photoelectric system defined by eight narrow bands between 0.7 and 1.1microns has been used to measure nearly all M supergiants that have beenclassified on the MK system. The photometric TiO and CN indicesreproduce the two-dimensional MK classifications to the accuracy of theMK types themselves. Mean fluxes and spectral classifications arepresented for 128 stars.
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Southern search for OH from M supergiants
Results are reported of a search for OH emission from about 50 southernM supergiants, and it is concluded that most optically identified Msupergiants do not have substantial emission at 1612 MHz. Fromexamination of the published OH profiles of unidentified Type II OH/IRstars, it is also concluded that only a small percentage (about 10%) ofthese stars have spectra similar to those of known OH supergiants,suggesting that Type II OH supergiants are an extremely rare class ofobject. A list of unidentified sources which may be supergiants isgiven.
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O stars and supergiants south of declination -53 0.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1976AJ.....81..116H&db_key=AST
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Infrared Excesses in the M Supergiants of H and χ Persei
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1973ApJ...186L.131C&db_key=AST
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Infrared Surveys of the Southern Milky way. II. Suspected Supergiant M Stars
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1972ApJ...176..623A&db_key=AST
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Spectroscopic and Photometric Observations of M Supergiants in Carina.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1972ApJ...172...75H&db_key=AST
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Estrellas Rojas entre Popa y Cruz.
Not Available
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INHABITED SKY
