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Grains in disks around young stars grow from interstellar submicron sizes to planetesimals over the course of several Myr. Thermal emission of large grains or pebbles can be best observed at cm wavelengths. However, other emission mechanisms can contribute. We aim to determine the mechanisms of cm emission for 3 T Tauri stars. WW Cha and RU Lup were recently found to have grain growth at least up to mm sizes in their circumstellar disks. CS Cha has similar indications for grain growth in its circumbinary disk. The T Tauri stars WW Cha and RU Lup were monitored over several years at mm and cm wavelengths, using ATCA. The new ATCA 7 mm system was also used to observe CS Cha. WW Cha was detected on several occasions at 7 and 16 mm. We obtained one detection of WW Cha at 3 cm and upper limits only at 6 cm. The emission at 16 mm was stable over days, months and years, but the emission at 3 cm is found to be variable. RU Lup was detected at 7 mm. It was observed at 16 mm 3 times and at 3 and 6 cm 4 times and found to be variable in all 3 wavebands. CS Cha was detected at 7 mm, but the S/N was too low to resolve the gap in the circumbinary disk. The emission at 3, 7 and 16 mm for WW Cha is well explained by thermal emission from mm and cm-sized pebbles. The cm spectral index is consistent with the emission from an optically-thick ionised wind, but the high variability of the cm emission points to a non-thermal contribution. The SEDs of RU Lup and CS Cha from 1 to 7 mm are consistent with thermal emission from mm-sized grains. The variability of the longer-wavelength emission for RU Lup and the negative spectral index suggest non-thermal emission.
We present Atacama Large Millimeter/submillimeter Array (ALMA) Band 6 observations of dust continuum emission of the disk around WW Cha. The dust continuum image shows a smooth disk structure with a faint (low-contrast) dust ring, extending from $sim
The young T Tauri star WW Cha was recently proposed to be a close binary object with strong infrared and submillimeter excess associated with circum-system emission. This makes WW Cha a very interesting source for studying the influence of dynamical
In the present study we aim to investigate the circumstellar environment of the spectroscopic binary T Tauri star CS Cha. From unresolved mid- to far-infrared photometry it is predicted that CS Cha hosts a disk with a large cavity. In addition, SED m
Gas plays a major role in the dynamical evolution of protoplanetary discs. Its coupling with the dust is the key to our understanding planetary formation. Studying the gas content is therefore a crucial step towards understanding protoplanetary discs
We have identified four circumstellar disks with a deficit of dust emission from their inner 15-50 AU. All four stars have F-G spectral type, and were uncovered as part of the Spitzer Space Telescope ``Cores to Disks Legacy Program Infrared Spectrogr