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The PDS 70 system has been subject to many studies in the past year following the discovery of two accreting planets in the gap of its circumstellar disk. Nevertheless, the mass accretion rate onto the star is still not well known. Here we determined the stellar mass accretion rate and its variability based on TESS and HARPS observations. The stellar light curve shows a strong signal with a $3.03pm0.06$ days period, which we attribute to stellar rotation. Our analysis of the HARPS spectra shows a rotational velocity of $vsin,i=16.0pm0.5,{rm km,s^{-1}}$, indicating that the inclination of the rotation axis is $50pm8$ degrees. This implies that the rotation axes of the star and its circumstellar disk are parallel within the measurement error. We apply magnetospheric accretion models to fit the profiles of the H$alpha$ line and derive mass accretion rates onto the star in the range of $0.6-2.2times10^{-10},{rm M_{odot}yr^{-1}}$, varying over the rotation phase. The measured accretion rates are in agreement with those estimated from NUV fluxes using accretion shock models. The derived accretion rates are higher than expected from the disk mass and planets properties for the low values of the viscous parameter $alpha$ suggested by recent studies, potentially pointing to an additional mass reservoir in the inner disk to feed the accretion, such as a dead zone. We find that the He I $lambda$10830 line shows a blueshifted absorption feature, indicative of a wind. The mass-loss rate estimated from the line depth is consistent with an accretion-driven inner disk MHD wind.
We present the first observational evidence for a circumplanetary disk around the protoplanet PDS~70~b, based on a new spectrum in the $K$ band acquired with VLT/SINFONI. We tested three hypotheses to explain the spectrum: Atmospheric emission from t
We present the results of a global, three-dimensional magnetohydrodynamics simulation of an accretion disk with a rotating, weakly magnetized central star. The disk is threaded by a weak, large-scale poloidal magnetic field, and the central star has
Transition discs are prime targets to look for protoplanets and study planet-disc interactions. We present VLT/SINFONI observations of PDS~70, a transition disc with a recently claimed embedded protoplanet. We take advantage of the angular and spectr
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} satellit
Diagnostics of electron temperature (T_e), electron density (n_e), and hydrogen column density (N_H) from the Chandra High Energy Transmission Grating spectrum of He-like Ne IX in TW Hydrae (TW Hya), in conjunction with a classical accretion model, a