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PDS 70 is a $sim$5 Myr old star with a gas and dust disc in which several proto-planets have been discovered. We present the first UV detection of the system along with X-ray observations taken with the textit{Neil Gehrels Swift Observatory} satellite. PDS 70 has an X-ray flux of 3.4$times 10^{-13}$ erg cm$^{-2}$ s$^{-1}$ in the 0.3-10.0 keV range, and UV flux (U band) of 3.5$times 10^{-13}$ erg cm$^{-2}$ s$^{-1}$ . At the distance of 113.4 pc determined from Gaia DR2 this gives luminosities of 5.2$times 10^{29}$ erg s$^{-1}$ and 5.4$times 10^{29}$ erg s$^{-1}$ respectively. The X-ray luminosity is consistent with coronal emission from a rapidly rotating star close to the log $frac{L_{mathrm{X}}}{L_{mathrm{bol}}} sim -3$ saturation limit. We find the UV luminosity is much lower than would be expected if the star were still accreting disc material and suggest that the observed UV emission is coronal in origin.
Optical/IR images of transition disks (TDs) have revealed deep intensity decrements in the rings of HAeBes HD142527 and HD100453, that can be interpreted as shadowing from sharply tilted inner disks, such that the outer disks are directly exposed to
We present observations of the young multiple system UX Tauri to look for circumstellar disks and for signs of dynamical interactions. We obtained SPHERE/IRDIS deep differential polarization images in the J and H bands. We also used ALMA archival CO
Nitrogen chemistry in protoplanetary disks and the freeze-out on dust particles is key to understand the formation of nitrogen bearing species in early solar system analogs. So far, ammonia has not been detected beyond the snowline in protoplanetary
Context: T Tauri stars have X-ray luminosities ranging from L_X = 10^28-10^32 erg/s. These luminosities are similar to UV luminosities (L_UV 10^30-10^31 erg/s) and therefore X-rays are expected to affect the physics and chemistry of the upper layers
Residual gas in disks around young stars can spin down stars, circularize the orbits of terrestrial planets, and whisk away the dusty debris that is expected to serve as a signpost of terrestrial planet formation. We have carried out a sensitive sear