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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.
| Results from the adaptive optics coronagraph at the William Herschel Telescope
Described here is the design and commissioning of a coronagraph facilityfor the 4.2-m William Herschel Telescope (WHT) and its Nasmyth AdaptiveOptics for Multi-purpose Instrumentation (NAOMI). The use of the NAOMIsystem gives an improved image resolution of ~0.15 arcsec at awavelength of 2.2μm. This enables the Optimised Stellar Coronagraphfor Adaptive optics (OSCA) to suppress stellar light using smallerocculting masks and thus allows regions closer to bright astronomicalobjects to be imaged. OSCA provides a selection of 10 differentocculting masks with sizes of 0.25-2.0arcsec in diameter, including twowith full grey-scale Gaussian profiles. There is also a choice ofdifferent sized and shaped Lyot stops (pupil plane masks). Computersimulations of the different coronagraphic options with the NAOMIsegmented mirror have relevance for the next generation of highlysegmented extremely large telescopes.
| Longterm Photometry of Variables at ESO - Part Two - the Second Data Catalogue 1986-1990
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1993A&AS..102...79S&db_key=AST
| Uvby-beta observations of 528 type B stars with V between the 8th and 9th magnitude
The paper presents uvby-beta measurements of 528 type B stars selectedfrom the SAO Catalog on the basis of two criteria: the spectral types inthe range B3-B5 and mV between the 8th and the 9th magnitude. Reddeningindependent (c1) values are estimated from the spectral classificationand compared to the observed values. No systematic trend with observed(b-y), H-beta, or spectral type appears to be present, but the range of(c1) residuals is surprisingly large. A rather large part of the starshas small beta values, smaller than for the BIa supergiants. Only twoare classified as O stars and most of them have the suffix e, ne, ornne. Most beta values for the O type stars are slightly above the upperlimit of 2.585 m.
| Long-term photometry of variables at ESO. I - The first data catalogue (1982-1986)
This paper presents the catalog of photometric data in the Stromgrensystem obtained during the first four years (October 1982 - September1986) of the Long-Term Photometry of Variables (LTPV) program at ESO.The data are available in computer-readable form.
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| Takýmyýldýz: | Kalkan |
| Sað Açýklýk: | 18h29m06.13s |
| Yükselim: | -04°26'53.4" |
| Görünürdeki Parlaklýk: | 10.173 |
| özdevim Sað Açýklýk: | 7.8 |
| özdevim Yükselim: | -24.2 |
| B-T magnitude: | 10.981 |
| V-T magnitude: | 10.24 |
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