Contingut
Imatges
Carregar la teva Imatge
DSS Images Other Images
Articles Relacionats
Catalogue of H-alpha emission stars in the Northern Milky Way
The ``Catalogue of Stars in the Northern Milky Way Having H-alpha inEmission" appears in Abhandlungen aus der Hamburger Sternwarte, Band XIin the year 1997. It contains 4174 stars, range {32degr <= l() II< 214degr , -10degr < b() II < +10degr } having the Hαline in emission. HBH stars and stars of further 99 lists taken from theliterature till the end of 1994 were included in the catalogue. We givethe cross-identification of stars from all lists used. The catalogue isalso available in the Centre de Données, Strasbourg ftp130.79.128.5 or http://cdsweb.u-strasbg.fr and at the HamburgObservatory via internet.
| Photometric Separation of Stellar Properties Using SDSS Filters
Using synthetic photometry of Kurucz model spectra, we explore thecolors of stars as a function of temperature, metallicity, and surfacegravity with Sloan Digital Sky Survey (SDSS) filters, u'g'r'i'z'. Thesynthetic colors show qualitative agreement with the few publishedobservations in these filters. We find that the locus of synthetic starsis basically two-dimensional for 4500 < T < 8000 K, whichprecludes simultaneous color separation of the three basic stellarcharacteristics we consider. Colors including u' contain the mostinformation about normal stellar properties; measurements in this filterare also important for selecting white dwarfs. We identify two differentsubsets of the locus in which the loci separate by either metallicity orsurface gravity. For 0.5 < g' - r' < 0.8 (corresponding roughly toG stars), the locus separates by metallicity; for photometric error of afew percent, we estimate metallicity to within ~0.5 dex in this range.In the range -0.15 < g' - r' < 0.00 (corresponding roughly to Astars), the locus shows separation by surface gravity. In both cases, weshow that it is advantageous to use more than two colors whendetermining stellar properties by color. Strategic observations in SDSSfilters are required to resolve the source of a ~5% discrepancy betweensynthetic colors of Gunn-Stryker stars, Kurucz models, and externaldeterminations of the metallicities and surface gravities. The syntheticstar colors can be used to investigate the properties of any normal starand to construct analytic expressions for the photometric prediction ofstellar properties in special cases.
| Catalogue of stars in the northern Milky Way having H-alpha in emission
Not Available
| The optical and near-infrared colors of galaxies. 2: Spectral classification
We have used optical and near-infrared photometry of a well definedsample of field galaxies with spectroscopic redshifts to study andcharacterize the trends and dispersions of rest-frame colors atintermediate redshifts of z less than or = 0.3. We have constructed asimple spectral synthesis model which serves to determine theinformation available in our five bands (U, J, F, N, and K) to constrainthe stellar composition of galaxies, as well as to classify spectrallyour sample. We find that a simple model consisting of two stellarspectral types can reproduce well the observed broadband colors, butonly if the types are allowed to vary. The five primary galaxy spectraltypes resulting from this model are bk, bm, am, fm, and gm (lower-caseletters refer to steller types B, K, etc.), and are distinct both instellar type and mixture. We describe how our spectral synthesis model,when fit to the observed colors of galaxies, provides an accurateinterpolative means for determining rest-frame colors. Thekappa-corrections calculated in this way are consistent with moresophisticated models and observed spectral energy distributions of localgalaxies. Color-luminosity effects are observed in both V-K and U-V forall galaxy types over a combined range of 10 magnitudes. The range ofcolors at a fixed absolute magnitude is comparable to the change in meancolor over the observed absolute magnitude range. In contrast to studiesof galaxies segregated by Hubble type, we find no evidence for a stronggalaxy spectral type dependence on the slope of the color-luminositycorrelation. If physical parameters, such as age and metallicity giverise to the relationship between color and luminosity, they mustconspire to produce similar effects for all galaxy spectral types.
| 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.
| Theoretical colours and isochrones for some Hubble Space Telescope colour systems. II
A grid of synthetic surface brightness magnitudes for 14 bandpasses ofthe Hubble Space Telescope Faint Object Camera is presented, as well asa grid of UBV, uvby, and Faint Object Camera surface brightnessmagnitudes derived from the Gunn-Stryker spectrophotometric atlas. Thesynthetic colors are used to examine the transformations between theground-based Johnson UBV and Stromgren uvby systems and the Faint ObjectCamera UBV and uvby. Two new four-color systems, similar to theStromgren system, are proposed for the determination of abundance,temperature, and surface gravity. The synthetic colors are also used tocalculate color-magnitude isochrones from the list of theoretical tracksprovided by VandenBerg and Bell (1990). It is shown that by using theappropriate filters it is possible to minimize the dependence of thiscolor difference on metallicity. The effects of interstellar reddeningon various Faint Object Camera colors are analyzed as well as theobservational requirements for obtaining data of a given signal-to-noisefor each of the 14 bandpasses.
| Some notes on the Gunn-Stryker spectrophotometry and synthetic VRI colors
Cousins VRI photometry is presented for 26 stars with continuous scansby Gunn and Stryker. This photometry is combined with literature dataand a few unpublished results to critique synthetic colors from theGunn-Stryker scans. For V - R, it is found that all pertinent resultsare consistent at the several-mmag level. For R - I, however, systematicdifferences are found which are most simply interpreted as a declinationeffect in the Gunn-Stryker scans. In addition, it is found that theGunn-Stryker synthetic colors are unexpectedly noisy, with sigma perdatum of about 0.02 mag. It is suggested that future users of theGunn-Stryker data keep both these effects in mind.
| Stellar spectrophotometric atlas, wavelengths from 3130 to 10800 A
Over the course of the past 10 years, a large body of homogeneousspectrophotometric data on relatively bright stars has been gathered toserve as a library with which to synthesize galaxy spectra in populationstudies. As the data might be generally useful, they are presented inthree tables. One hundred seventy-five (175) stars were selected, mostfrom the Navy photometric catalog. Covered are complete ranges ofspectral type and luminosity class. Normalized spectral energydistributions of these stars in pictorial form are provided along withtables of calculated colors, scan line and continuum indices, and someinformation on the relation of the scan colors to real photometricsystems.
| Spectral types for early-type stars observed by SKYLAB
MK spectral types are presented for 246 early-type stars observed withthe S-019 ultraviolet stellar astronomy experiment on Skylab. K-linetypes are also given where applicable, and various peculiar stars areidentified. The peculiar stars include five silicon stars, a shell star,a helium-rich star, a silicon-strontium star, a chromium-europium star,and two marginal metallic-line stars.
| Observations spectroscopiques d'etoiles Be.
Not Available
| Axial Rotation in the Later B-Type Emission-Line Stars
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1966ApJ...145..121S&db_key=AST
| General Catalogue of Stellar Radial Velocities
Not Available
| Supplement to the Mount Wilson Catalogue and Bibliography of Stars of Classes B and a whose Spectra have Bright Hydrogen Lines.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1943ApJ....98..153M&db_key=AST
| The radial velocities of 500 stars.
Not Available
| Five Newly Discovered Be Stars
Not Available
| Five newly discovered Be stars (1939).
Not Available
|
Enviar un nou article
Enllaços Relacionats
- - No s'ha trobat enllaços -
Enviar un nou enllaç
Membre dels grups següents:
|
Dades d'Observació i Astrometria
| Constel·lació: | Cygnus |
| Ascensió Recta: | 20h00m07.06s |
| Declinació: | +32°47'22.8" |
| Magnitud Aparent: | 7.273 |
| Distancia: | 568.182 parsecs |
| Moviment propi RA: | 1.5 |
| Moviment propi Dec: | -2.6 |
| B-T magnitude: | 7.221 |
| V-T magnitude: | 7.269 |
Catàlegs i designacions:
|
