Contenuti
Immagini
Carica la tua immagine
DSS Images Other Images
Articoli relazionati
Effective temperature scale and bolometric corrections from 2MASS photometry
We present a method to determine effective temperatures, angularsemi-diameters and bolometric corrections for population I and II FGKtype stars based on V and 2MASS IR photometry. Accurate calibration isaccomplished by using a sample of solar analogues, whose averagetemperature is assumed to be equal to the solar effective temperature of5777 K. By taking into account all possible sources of error we estimateassociated uncertainties to better than 1% in effective temperature andin the range 1.0-2.5% in angular semi-diameter for unreddened stars.Comparison of our new temperatures with other determinations extractedfrom the literature indicates, in general, remarkably good agreement.These results suggest that the effective temperaure scale of FGK starsis currently established with an accuracy better than 0.5%-1%. Theapplication of the method to a sample of 10 999 dwarfs in the Hipparcoscatalogue allows us to define temperature and bolometric correction (Kband) calibrations as a function of (V-K), [m/H] and log g. Bolometriccorrections in the V and K bands as a function of T_eff, [m/H] and log gare also given. We provide effective temperatures, angularsemi-diameters, radii and bolometric corrections in the V and K bandsfor the 10 999 FGK stars in our sample with the correspondinguncertainties.
| ROSAT HRI catalogue of X-ray sources in the SMC region
During the operational phase of the ROSAT satellite between 1990 and1998 the X-ray telescope pointed 71 times to the Small Magellanic Cloud(SMC) for observations with the High Resolution Imager (HRI), covering afield of 5 degr x 5 degr. From these data a catalogue of 121 discreteX-ray sources was derived. By cross-correlating the source cataloguewith the SIMBAD data base and the TYCHO catalogue, the systematicpositional error of the HRI source positions could be reduced. In totalthe X-ray position for 99 HRI sources was corrected yielding positionalerrors between 1'' and 16 arcsec. The HRI catalogue was alsocross-correlated with the catalogues derived from the ROSAT PositionSensitive Propotional Counter (PSPC) pointings (Kahabka et al.\cite{kah99}; Haberl et al. \cite{hab00}). For 75 HRI sources PSPCcounterparts were found and thus hardness ratios are given. With thehelp of the information obtained from the cross-correlations 56 HRIsources were identified with objects of known or proposed nature. Fourforeground stars, six supernova remnants, four supersoft sources, 12X-ray binaries, and one AGN were detected by the HRI. Based on theexistence of a likely optical counterpart or properties like hardnessratio and X-ray to optical flux ratio, further 15 HRI sources wereclassified into different source types.
| A ROSAT PSPC catalogue of X-ray sources in the SMC region
We present a catalogue of 517 discrete X-ray sources in a 6°x6°\field covering the Small Magellanic Cloud (SMC). The catalogue wasderived from the pointed ROSAT PSPC observations performed betweenOctober 1991 and May 1994 and is complementary to the Large MagellanicCloud (LMC) catalogue published by \cite[Haberl & Pietsch(1999).]{H99} We followed the same identification scheme and used, amongother information, X-ray hardness ratios and spatial extent to classifyunknown sources as candidates for active galactic nuclei (AGN),foreground stars, supernova remnants (SNRs), supersoft sources (SSSs)and X-ray binaries. For 158 sources a likely source type is given, fromwhich 46 sources are suggested as background AGN (including candidatesresulting from a comparison of X-ray and radio images). Nearly all ofthe X-ray binaries known in the SMC were detected in ROSAT PSPCobservations; most of them with luminosities below \ergs{36} suggestingthat the fraction of high luminosity X-ray binary systems in theMagellanic Clouds (MCs) is not significantly larger than in our galaxy.Seventeen X-ray sources are associated with SNRs found in earlier workand we suggest here two additional extended sources as SNR candidates.Three very soft sources are newly classified as SSSs from which one isidentified with the symbiotic star LIN 358 in the SMC. Table 2 is onlyavailable in electronic form at CDS via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| A ROSAT PSPC X-ray survey of the Small Magellanic Cloud
We present the results of a systematic search for point-like andmoderately extended soft (0.1-2.4 keV) X-ray sources in a raster of ninepointings covering a field of 8.95\ deg(2) and performed with the ROSATPSPC between October 1991 and October 1993 in the direction of the SmallMagellanic Cloud (SMC). We detect 248 objects which we include in thefirst version of our SMC catalogue of soft X-ray sources. We set upseven source classes defined by selections in the count rate, hardnessratio and source extent. We find five high luminosity super-soft sources(1E 0035.4-7230, 1E 0056.8-7146, RX J0048.4-7332, RX J0058.6-7146 and RXJ0103-7254), one low-luminosity super-soft source RX J0059.6-7138correlating with the planetary nebula L357, 51 candidate hard X-raybinaries including eight bright hard X-ray binary candidates, 19supernova remnants (SNRs), 19 candidate foreground stars and 53candidate background active galactic nuclei (and quasars). We give alikely classification for ~ 60% of the catalogued sources. The totalcount rate of the detected point-like and moderately extended sources inour catalogue is 6.9 +/- 0.3 s(-1) , comparable to the backgroundsubtracted total rate from the integrated field of ~ 6.1+/-0.1 s(-1) .Table 1 is also available in electronic from at the CDS via anonymousftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| Positional reference stars in the Magellanic Clouds
The equatorial coordinates are determined of 926 stars (mainly ofgalactic origin) in the direction of the Magellanic Clouds at the meanepoch T = 1978.4 with an overall accuracy characterized by the meanvalues of the O-C coordinates, Sa = 0.35 arcsec and Sd = 0.38 arcsec,calculated from the coordinates of the Perth reference stars. Thesevalues are larger than the accuracy expected for primary standard stars.They allow the new positions to be considered as those of reliablesecondary standard stars. The published positions correspond to anunquestionable improvement of the quality of the coordinates provided inthe current catalogs. This study represents an 'astrometric step' in thestarting of a 'Durchmusterung' of the Magellanic Clouds organized by deBoer (1988, 1989).
| Estimation of stellar intrinsic colours, distances and colour excesses based on the Stromgren and H-beta photometry of 804 B, A, and F stars in 10 Selected Areas
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1989A&AS...78..105F&db_key=AST
| Four-colour UVBY and H-beta photometry of all A and F stars brighter than MPG of about 11.0 mag in 4 Selected Areas at intermediate galactic latitudes
As a second part of an investigation of the distribution of interstellardust in the solar vicinity, uvby-beta photometry has been obtained for260 stars of spectral types A and F, and brighter than mpg of11.0 mag in four Kapteyn's Selected Areas. The observed areas are: SA95, SA 120, SA 168, and SA 200. They are centered at intermediategalactic latitudes, in the range from b of about -38 deg to -42 deg.From the observed (b-y) versus beta diagrams it can be seen that starsin SA 95 are strongly affected by reddening, while the other areas showvery little absorption.
| Interstellar polarization from observations of A and F stars in high and intermediate galactic latitudes, and from stars in the Mathewson and Ford polarization catalogue
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1986A&AS...64..487K&db_key=AST
| Sir John Herschel's Observations of Stars in the Small Magellanic Cloud
Not Available
| The interstellar reddening of the globular cluster 47 Tuc.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1975PASP...87..561C&db_key=AST
| Catalogue et bibliographie des étoiles A à spectre particulier
Not Available
|
Sottometti un nuovo articolo
Link relazionati
Sottometti un nuovo link
Membro dei seguenti gruppi:
|
Osservazione e dati astrometrici
| Costellazione: | Tucano |
| Ascensione retta: | 00h40m00.70s |
| Declinazione: | -73°45'42.6" |
| Magnitudine apparente: | 8.495 |
| Distanza: | 149.477 parsec |
| Moto proprio RA: | 24.3 |
| Moto proprio Dec: | -6 |
| B-T magnitude: | 8.998 |
| V-T magnitude: | 8.537 |
Cataloghi e designazioni:
|
