Jorge Ricardo Ducati

Intrinsic colors of stars in the near-infrared

Intrinsic infrared colors of stars in the Johnson 11 color system are derived. The database is a list of 3946 stars with observations in UBVRIJHKLMN, of all spectral types and luminosity classes, including carbon, T Tauri, and Wolf-Rayet stars. Intrinsic colors were derived from the zero-reddening curve that can be defined in the bluer side of temperature versus observed color diagrams. In a sample of stars of the same spectral type, the bluest stars are considered to have an observed color very near their intrinsic color. The comparison with former derivations from Johnson and Koornneef presents significant differences: new M and N colors, for all spectral types, are bluer than published values, the differences being more important for giants and supergiants; the amplitude of color values in these new results is wider.

Assessing the MODIS Crop Detection Algorithm for Soybean Crop Area Mapping and Expansion in the Mato Grosso State, Brazil

Estimations of crop area were made based on the temporal profiles of the Enhanced Vegetation Index (EVI) obtained from moderate resolution imaging spectroradiometer (MODIS) images. Evaluation of the ability of the MODIS crop detection algorithm (MCDA) to estimate soybean crop areas was performed for fields in the Mato Grosso state, Brazil. Using the MCDA approach, soybean crop area estimations can be provided for December (first forecast) using images from the sowing period and for February (second forecast) using images from the sowing period and the maximum crop development period. The area estimates were compared to official agricultural statistics from the Brazilian Institute of Geography and Statistics (IBGE) and from the National Company of Food Supply (CONAB) at different crop levels from 2000/2001 to 2010/2011. At the municipality level, the estimates were highly correlated, with R 2 = 0.97 and RMSD = 13,142 ha. The MCDA was validated using field campaign data from the 2006/2007 crop year. The overall map accuracy was 88.25%, and the Kappa Index of Agreement was 0.765. By using pre-defined parameters, MCDA is able to provide the evolution of annual soybean maps, forecast of soybean cropping areas, and the crop area expansion in the Mato Grosso state.

Near-infrared surface photometry of early-type galaxies

CCD infrared ( JHK s ) photometry was performed on a sample of 10 elliptical and 2 lenticular galaxies. Isophotal parameters, brightness profiles, integrated colors and color gradients are presented. Color gradients found are very weak, showing bluer colors towards the outer regions. The colors of the sample galaxies are compatible with stellar populations like those found in metal-rich clusters of the Galaxy; objects NGC 7192, NGC 7562 and NGC 7619 are compatible with less metal-rich populations. The brightness profile of most galaxies is well described by the

Multichromatic colour–magnitude diagrams of the globular cluster NGC 6366

r^{1/4}

Spectral features of vineyards in south Brazil from ASTER imaging.

law. The profiles of NGC 1600 and NGC 720 are described by Sersics law with

Algorithm for Soybean Classification Using Medium Resolution Satellite Images

n\sim{1.5}

Spectral Discrimination of Grape Varieties and a Search for Terroir Effects Using Remote Sensing

and

Analysis of soybean cropland expansion in the southern Brazilian Amazon and its relation to economic drivers

n\sim{1.8}

The XDSpres CL-Based Package for Reducing OSIRIS Cross-dispersed Spectra

respectively. The infrared effective radius of the objects studied is typically one half of its counterpart in the B band, which can be an indication that the stellar population that dominates the infrared emission is more concentrated in the central regions. We show that the sample satisfies the Fundamental Plane relation of elliptical galaxies in the infrared, with an rms scatter of 0.20 for J and H and 0.23 for K s .

Avaliação do impacto da resolução espacial de modelos digitais de elevação sobre a estimativa de formação de ozônio superficial usando Models-3

We present multichromatic isochrone fits to the colour magnitude data of the globular cluster NGC6366, based on HST ACS/WFC and SOAR photometric data. We corrected the photometric data for differential reddening and calculated the mean ridge line of the colour magnitude diagrams. We compared the isochrones of Dartmouth Stellar Evolution Database and PAdova and TRieste Stellar Evolution Code both with microscopic diffusion starting on the main sequence. Bracketing all previous determinations of this cluster we tested metallicities from [Fe/H]=–1.00 to [Fe/H]=–0.50, and ages from 9 to 13 Gyrs. After determining the total to selective extinction ratio only from stars belonging to this cluster, RV = 3.06±0.14, we found the parameters for this cluster to be E(B V ) = 0.69 ± 0.02(int) ±0.04(ext), (m M)V = 15.02 ± 0.07(int) ±0.13(ext), Age = 11 ± 1.15Gyr. Evolutionary models fail to reproduce the low–Teff sequence in multi–band colour magnitude diagrams, indicating that they still have an incomplete physics. We found that the Dartmouth Stellar Evolution Database isochrones fit better the sub giant branch and low main sequence than the PAdova and TRieste Stellar Evolution Code.