Radiação infravermelha e a detecção de discos circunstelares em torno de anãs brancas

Abstract

This work describes the process of detection of debris disks around white dwarfs (WDs), using excesses of infrared radiation (IR) found on the spectral energy distribution (SED) of such stars. With an initial sample of 11.407 objects from the VST ATLAS white dwarf candidates cat. Fusillo et al. (2017) catalogue, 369 stars were selected where the spectral type was already con rmed as "WD". From those, 115 showed photometry in all wavelenght bands from WISE (3.4µm, 4.6µm, 12µm and 22µm) and 2MASS (1.24µm, 1.63µm and 2.16µm). Using the online tool VOSA, we've calculated the t to the SEDs, by selecting the Kurucz model. Finally, 4 stars were selected showing a possible IR excess on W1 and W2 bands, that was reinforced by the visual inspection, all being point sources. By calculating the signi cance of excess (χλ), we've considered as valid the results on wich χλ ≥ 3 in any of the bands with excess. A value of χλ < 3 was noticed on the W2 band of the star J003011.69-374048.4. However, all 4 stars presented χλ ≥ 3 on the W1 WISE band, what keeps them as positive results. Finally, the disk temperatures were calculated, varying from 930 K to 1750K.