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The V-band Empirical Mass-luminosity Relation for Main Sequence Stars
Stellar mass is an indispensable parameter in the studies of stellarphysics and stellar dynamics. On the one hand, the most reliable way todetermine the stellar dynamical mass is via orbital determinations ofbinaries. On the other hand, however, most stellar masses have to beestimated by using the mass luminosity relation (MLR). Therefore, it isimportant to obtain the empirical MLR through fitting the data ofstellar dynamical mass and luminosity. The effect of metallicity canmake this relation disperse in the V-band, but studies show that this ismainly limited to the case when the stellar mass is less than0.6M? Recently, many relevant data have been accumulatedfor main sequence stars with larger masses, which make it possible tosignificantly improve the corresponding MLR. Using a fitting methodwhich can reasonably assign weights to the observational data includingtwo quantities with different dimensions, we obtain a V-band MLR basedon the dynamical masses and luminosities of 203 main sequence stars. Incomparison with the previous work, the improved MLR is statisticallysignificant, and the relative error of mass estimation reaches about 5%.Therefore, our MLR is useful not only in the studies of statisticalnature, but also in the studies of concrete stellar systems, such as thelong-term dynamical study and the short-term positioning study of aspecific multiple star system.
| FAUST observations in the Fourth Galactic Quadrant*
We analyse UV observations with FAUST of four sky fields in the generaldirection of the Fourth Galactic Quadrant, in which we detect 777 UVsources. This is ~50 per cent more than detected originally by Bowyer etal. We discuss the source detection process and the identification of UVsources with optical counterparts. For the first time in this project weuse ground-based objective-prism information for two of the fields, toselect the best-matching optical objects with which to identify the UVsources. Using this, and correlations with existing catalogues, wepresent reliable identifications for ~75 per cent of the sources. Mostof the remaining sources have assigned optical counterparts but, lackingadditional information, we offer only plausible identifications. Wediscuss the types of objects found, and compare the observed populationwith predictions of our UV Galaxy model.
| 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.
| A catalog of far-ultraviolet point sources detected with the fast FAUST Telescope on ATLAS-1
We list the photometric measurements of point sources made by the FarUltraviolet Space Telescope (FAUST) when it flew on the ATLAS-1 spaceshuttle mission. The list contains 4698 Galactic and extragalacticobjects detected in 22 wide-field images of the sky. At the locationssurveyed, this catalog reaches a limiting magnitude approximately afactor of 10 fainter than the previous UV all-sky survey, TDl. Thecatalog limit is approximately 1 x 10-14 ergs A sq cm/s,although it is not complete to this level. We list for each object theposition, FUV flux, the error in flux, and where possible anidentification from catalogs of nearby stars and galaxies. Thesecatalogs include the Michigan HD (MHD) and HD, SAO, the HIPPARCOS InputCatalog, the Position and Proper Motion Catalog, the TD1 Catalog, theMcCook and Sion Catalog of white dwarfs, and the RC3 Catalog ofGalaxies. We identify 2239 FAUST sources with objects in the stellarcatalogs and 172 with galaxies in the RC3 catalog. We estimate thenumber of sources with incorrect identifications to be less than 2%.
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| Takýmyýldýz: | Erbogan |
| Sað Açýklýk: | 13h00m44.43s |
| Yükselim: | -39°17'42.7" |
| Görünürdeki Parlaklýk: | 8.232 |
| Uzaklýk: | 120.192 parsek |
| özdevim Sað Açýklýk: | -82.4 |
| özdevim Yükselim: | -23 |
| B-T magnitude: | 8.707 |
| V-T magnitude: | 8.272 |
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