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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.
| An isolated, well-defined infrared cirrus cloud
High spatial resolution H I measurements of a high-latitude FIR cirruscloud (l = 9 deg, b = 51 deg) were obtained with the Arecibo 310 mtelescope. The cloud is well isolated spatially and has a velocitywell-separated from other H I clouds, providing an ideal laboratory forstudying diffuse interstellar clouds. The Iv(100)/N(H) andIv(60)/Iv(100) ratios are consistent with the Draine and Anderson modelwhich includes a distribution of grain sizes down to 3 A. The smallgrains undergo transient heating and affect the 60 micron FIR continuumemission. Current models, however, underpredict Iv(12)/Iv(100) andIv(25)/Iv(100) by more than a factor of 2. The effects small grains haveon the thermal equilibrium of diffuse interstellar clouds are discussed.
| 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
| UVBY beta photometry of 210 B, A, and F stars in ten areas centered on extragalactic radio sources at high northern galactic latitudes
As part of a study of the reddening properties of the interstellarmedium at the South Galactic pole and particularly along the southernpart of the galactic plane, a catalog of ubvy beta photometry of 210 B,A, and F stars in 10 areas of equal size covering 160 sq deg atlatitudes higher than +30 deg is presented. Each of the observed areasis centered at radio sources that have emission or absorption in the21-cm line; and the main aim of the study is to obtain color excessesfor a comparison of neutral hydrogen column densities, tentativelyassociated with distinct clouds and with the occurrence of dust in theseclouds. V, (b-y), m1, c1, and beta are presented for the 210 stars.
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| Takýmyýldýz: | Yilan |
| Sað Açýklýk: | 15h13m43.23s |
| Yükselim: | +07°41'18.7" |
| Görünürdeki Parlaklýk: | 9.405 |
| özdevim Sað Açýklýk: | 10 |
| özdevim Yükselim: | -7.7 |
| B-T magnitude: | 9.834 |
| V-T magnitude: | 9.441 |
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