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מאמרים קשורים
Multi-wavelength observations and modelling of shock-cloud interaction regions in the Vela Supernova Remnant
We present optical photometric and spectrophotometric observations oftwo selected filaments near the North rim of the Vela supernova remnantalso observed in UV with the International Ultraviolet Explorer, and inX-rays with the ROSAT PSPC detector. From the optical data, we havederived spatially-resolved ( ~ 3'') profiles of severalemission lines across the filaments, which allowed us to resolve thepost-shock region. Starting from model-independent line ratiodiagnostics, we have estimated densities (/line{n}=3.2-8.2cm-3), temperatures (T=3-10x 104 K), pressures(P=2.8x 10-10 dyne cm-2) and ambient magneticfields (B=50-85 mu G) in the post-shock flow. We have also found clearevidence of a relative displacement between the X-ray emission, theemission in the Hα line and the emission in the [O III] line. Wehave compared the measured displacement, the width of the filaments inHα and [O III], and the peak values of selected line ratios withthe predictions of a radiative shock model which describes in detail thestructure of the post-shock region. Shock models with velocities aroundv_s=110 km sec-1 are shown to be consistent with the opticaland UV observations if we assume that the direction of propagation istilted with respect to the line of sight. The layout of the X-ray andoptical emission of the filament and their thermodynamical propertiesstrongly suggest that the shock is travelling along increasing densitygradient.
| Two-colour photometry for 9473 components of close Hipparcos double and multiple stars
Using observations obtained with the Tycho instrument of the ESAHipparcos satellite, a two-colour photometry is produced for componentsof more than 7 000 Hipparcos double and multiple stars with angularseparations 0.1 to 2.5 arcsec. We publish 9473 components of 5173systems with separations above 0.3 arcsec. The majority of them did nothave Tycho photometry in the Hipparcos catalogue. The magnitudes arederived in the Tycho B_T and V_T passbands, similar to the Johnsonpassbands. Photometrically resolved components of the binaries withstatistically significant trigonometric parallaxes can be put on an HRdiagram, the majority of them for the first time. Based on observationsmade with the ESA Hipparcos satellite.
| The ROSAT all-sky survey catalogue of optically bright late-type giants and supergiants
We present X-ray data for all late-type (A, F, G, K, M) giants andsupergiants (luminosity classes I to III-IV) listed in the Bright StarCatalogue that have been detected in the ROSAT all-sky survey.Altogether, our catalogue contains 450 entries of X-ray emitting evolvedlate-type stars, which corresponds to an average detection rate of about11.7 percent. The selection of the sample stars, the data analysis, thecriteria for an accepted match between star and X-ray source, and thedetermination of X-ray fluxes are described. Catalogue only available atCDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| Large and kinematically unbiased samples of G- and K-type stars. IV - Evolved stars of the old disk population
Modified Stromgren and (R,I) photometry, along with DDO and Genevaphotometry, are presented for a complete sample of evolved old-disk Gand K giants in the Bright Star Catalogue. Stars with ages of between1.5 x 10 to the 9th and 10 to the 10th yr are found to have anear-normal distribution of heavy element abundances, centered on anFe/H abundance ratio of -0.1 dex. The old disk clusters NGC 3680 and IC4651 contain red-straggler young-disk giants that are probablycontemporaries of the blue stragglers in the clusters.
| Large and kinematically unbiased samples of G- and K-type stars. II - Observations of evolved stars in the Bright Star sample. III - Evolved young disk stars in the Bright Star sample
Four color and RI observations were obtained for a large sample ofG-type and K-type stars in the Bright Star Catalogue. Data are firstpresented for 110 evolved stars. Photometry of evolved young diskpopulation stars have then been calibrated for luminosity, reddening,and metallicity on the basis of results for members of the Hyades andSirius superclusters. New DDO results are given for 120 stars.
| 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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משמש של הקבוצה הבאה
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תצפית ומידע אסטרומטרי
| קבוצת-כוכבים: | שדרית |
| התרוממות ימנית: | 06h46m41.50s |
| סירוב: | -54°41'41.0" |
| גודל גלוי: | 6.46 |
| מרחק: | 127.065 פארסק |
| תנועה נכונה: | -44.3 |
| תנועה נכונה: | 13.5 |
| B-T magnitude: | 7.66 |
| V-T magnitude: | 6.634 |
קטלוגים וכינוים:
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