Published February 26, 2021 | Version v1
Poster Open

Probing the magnetospheric accretion region of the young system DoAr 44 using VLTI/GRAVITY

  • 1. IPAG

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Description

Young stars accrete material from their circumstellar disk through magnetically-controlled funnel flows. This so-called magnetospheric accretion process is central to the properties of young systems and not yet fully deciphered. We report here on an attempt to directly probe the star-disk interaction region a scale of less than 0.1 au in the young system DoAr 44, using with VLTI/GRAVITY in the K-band. We computed interferometric visibilities and phases in the continuum and in the Brγ line in order to constrain the extent and geometry of the emitting regions. We resolve the continuum emission of the inner dusty disk and measure a half-flux radius of 0.14 au. We show that Brγ emission arises from an even more compact region than the inner disk, with an upper limit of 0.047 au (∼5 R). Differential phase measurements between the Brγ line and the continuum allow us to measure the astrometric displacement of the Brγ line-emitting region relative to the continuum on a scale of a few tens of microarcsec, corresponding to a fraction of the stellar radius. Our results can be accounted for by a simple geometric model where the Brγ line emission arises from a compact region interior to the inner disk edge, on a scale of a few stellar radii, fully consistent with the concept of magnetospheric accretion process in low-mass young stellar systems.

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Funding

SPIDI – Star-Planet-Inner Disk Interactions (SPIDI): unveiling the formation and evolution of inner planetary systems 742095
European Commission