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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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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An atlas of stellar spectra between 2.00 and 2.45 microns
Spectra between 2.00 and 2.45 microns, with a resolution of about 0.02micron are presented for a sample of 73 stars. These stars include asupergiant, giants, dwarfs and subdwarfs, and have a range in chemicalabundance from about -2 to +0.5 dex.
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Search for wide binaries in the Yale Bright Star Catalogue
A specific scheme for identifying wide binary candidates in the YaleBright Star Catalogue is presented. The choice of criteria for selectingcandidates is discussed, and the final criteria are used to compile apreliminary list of candidates which is presented and discussed. Thestatistics of the candidate list are characterized, and the list is usedto compute upper bounds on the wide binary density using a simpletheoretical model.
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The cool components of symbiotic stars. I - Optical spectral types
An analysis of prominent absorption features on red spectra of symbioticstars is presented. The depths of TiO and VO bands appear to becorrelated with the brightness of the system; this behavior is probablythe result of the secondary star heating the outer atmosphere of thecool giant. New spectral types and luminosity classes for the coolcomponents of symbiotics are derived, and these classifications suggesta division into semidetached systems and detached systems. Mass-lossrates for detached symbiotics, which do not contain Mira variables,remain higher than those estimated for single red giants of the samespectral type, suggesting that the presence of a binary companionenhances mass loss in these objects.
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Mass-to-light ratios in elliptical galaxies
Medium-resolution infrared CVF spectra of the 2.3-micron CO absorptionfeature sensitive to stellar luminosity class is obtained for a sampleof elliptical galaxies and standard stars. These are the highest-qualityspectra of this feature published and have the potential of determiningrelative numbers of late-type giants and cool main-sequence dwarfs inelliptical galaxies more accurately than previous narrow-band filtermeasurements. A synthesis technique based on data on Baade's window isintroduced to investigate the limits on numbers of low-mass stars.Systematic uncertainties in the synthesis are introduced by inadequateknowledge about Baade's window, while the main statistical uncertaintydue to the large errors on published broadband colors of ellipticalgalaxies. Synthesis based on a narrow-band filter CO index is found tosuffer from uncertain K corrections and difficulties with the continuumdetermination. Resulting mass-to-light ratios are M/L (solar bolometric)= 2.5-5.0.
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E. W. Fick Observatory stellar radial velocity measurements. I - 1976-1984
Stellar radial velocity observations made with the large vacuumhigh-dispersion photoelectric radial velocity spectrometer at FickObservatory are reported. This includes nearly 2000 late-type starsobserved during 585 nights. Gradual modifications to this instrumentover its first eight years of operation have reduced the observationalerror for high-quality dip observations to + or - 0.8 km/s.
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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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Radial velocities of southern stars obtained with the photoelectric scanner CORAVEL. III - 790 late-type bright stars
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1985A&AS...59...15A&db_key=AST
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The radial velocities of 116 southern red stars
Using a photoelectric speedometer based on the radial velocityspectrometer of Griffin (1967), radial velocities of 116 southern redstars, many of them semi-regular variables, were measured. Theinstrument was placed at the Newtonian focus of the 130-inch (4.2-m)camera of the Coude spectrograph of the Mount Stromlo 74-inch (1.88-m)reflector. The stellar spectrum was focused on a mask 50 mm in length,designed to match the spectrum of the M-giant Beta Pegasi. The inversedispersion was 2.5 angstroms per millimeter in the second order. Thewavelength range used (5338-5449 angstroms) was chosen because it isbetween two TiO bands and so suffers less blanketing in M stars. Resultsare tabulated and compared with standard values.
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Radial velocities of southern HR stars. II
Fick Observatory's second major installment of radial-velocitymeasurements of bright southern stars is presented. This includes 373radial-velocity measurements for 90 stars which were obtained betweenJanuary 1978 and June 1981. Fifteen new possible velocity variables andone new double-line spectroscopic binary (HD 1782) have been detected.Subsequent velocity measurements of stars from the first southern HRstudy (Beavers and Eitter, 1980) found that (1) two stars (HR 0745 andHR 5428), originally classified as possible variables, are actuallyconstant velocity variables, and that (2) HR 0953 is a definite velocityvariable covering a range of at least -1 to +14 km/sec. This study, whencombined with the earlier southern HR observations and those reported byGriffin (1972), result in a total of 280 HR objects with newradial-velocity determinations.
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Photometric studies of composite stellar systems. II - Observations of H2O absorption and the coolest stellar component of E and S0 galaxies
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1978ApJ...220..442A&db_key=AST
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Photometric studies of composite stellar systems. I - CO and JHK observations of E and S0 galaxies
Multiaperture infrared photometric observations of the central regionsof 51 early-type galaxies and of the integrated light of five globularclusters are presented. These data are compared with selected opticalobservations and with various model predictions. The main results of thework are: (1) the observed parameters for the brighter galaxies,particularly the CO index and the V-K color, agree with the predictionsof stellar synthesis models characterized by giant-dominated populationswith mass/visual luminosity ratios less than 10; (2) the galaxianbroad-band colors tend to redden with increasing luminosity anddecreasing aperture size; (3) for the globular clusters, there isevidence that the integrated colors become redder with increasingmetallicity; and (4) in bright galaxies the relative changes of U-V,V-J, and J-K as functions of radius may differ from the relative changesas functions of luminosity at a fixed radius.
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Narrow-Band and Broad-Band Photometry of Red Stars. III. Southern Giants
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1970ApJ...161..199E&db_key=AST
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- and Broad-Band Photometry of Red Stars. Northern Giants
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1967ApJS...14..307E&db_key=AST
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INHABITED SKY
