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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.
| A catalogue of soft X-ray sources in the galactic center region
We present a catalogue of 107 point-like X-ray sources derived from asystematic analysis of all the ROSAT PSPC observations of the galacticcenter region performed in 1992-1993. Besides SgrA*, the massive blackhole at the galactic center, 41 X-ray sources have been positionallyassociated with already classified objects. Twenty are identified withforeground stars and five with known Low Mass X-ray Binaries. Themajority of the sources in our catalogue still remains unidentified.They are hard and/or severely absorbed and probably represent a largepopulation of X-ray binaries located in the galactic center region,accreting at low accretion rates, and still largely unknown.
| The Henry Draper Extension Charts: A catalogue of accurate positions, proper motions, magnitudes and spectral types of 86933 stars
The Henry Draper Extension Charts (HDEC), published in the form offinding charts, provide spectral classification for some 87000 starsmostly between 10th and 11th magnitude. This data, being highlyvaluable, as yet was practically unusable for modern computer-basedastronomy. An earlier pilot project (Roeser et al. 1991) demonstrated apossibility to convert this into a star catalogue, using measurements ofcartesian coordinates of stars on the charts and positions of theAstrographic Catalogue (AC) for subsequent identification. We presenthere a final HDEC catalogue comprising accurate positions, propermotions, magnitudes and spectral classes for 86933 stars of the HenryDraper Extension Charts.
| Walraven photometry of nearby southern OB associations
Homogeneous Walraven (VBLUW) photometry is presented for 5260 stars inthe regions of five nearby southern OB associations: Scorpio Centaurus(Sco OB2), Orion OB1, Canis Major OB1, Monoceros OB1, and Scutum OB2.Derived V and (B - V) in the Johnson system are included.
| UVBY observations of A, F, G and K field stars
Photoelectric data in the uvby system have been obtained for about 800southern stars of the Hipparcos Input Catalog (Grenon, 1982, 1985). Mostof the stars are F and G main sequence and fall in the magnitude range V= 8-11.
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| Takýmyýldýz: | Yay |
| Sað Açýklýk: | 17h49m41.79s |
| Yükselim: | -29°16'57.1" |
| Görünürdeki Parlaklýk: | 9.519 |
| özdevim Sað Açýklýk: | 6.5 |
| özdevim Yükselim: | 22.2 |
| B-T magnitude: | 10.031 |
| V-T magnitude: | 9.562 |
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