Poster Open Access

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

Bouvier Jerome; Perraut Karine; Alecian Evelyne

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<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
<dc:contributor>Wolk, Scott</dc:contributor>
<dc:creator>Bouvier Jerome</dc:creator>
<dc:creator>Perraut Karine</dc:creator>
<dc:creator>Alecian Evelyne</dc:creator>
<dc:date>2021-02-26</dc:date>
<dc: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 Br$\gamma$ 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 Br$\gamma$ emission arises from an even more compact region than the inner disk, with an upper limit of 0.047 au (∼5 R$_\star$). Differential phase measurements between the Br$\gamma$ line and the continuum allow us to measure the astrometric displacement of the Br$\gamma$ 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 Br$\gamma$ 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.</dc:description>
<dc:identifier>https://zenodo.org/record/4563911</dc:identifier>
<dc:identifier>10.5281/zenodo.4563911</dc:identifier>
<dc:identifier>oai:zenodo.org:4563911</dc:identifier>
<dc:relation>info:eu-repo/grantAgreement/EC/H2020/742095/</dc:relation>
<dc:relation>doi:10.5281/zenodo.4563910</dc:relation>
<dc:relation>url:https://zenodo.org/communities/coolstars20half</dc:relation>
<dc:rights>info:eu-repo/semantics/openAccess</dc:rights>
<dc:subject>Young stars</dc:subject>
<dc:title>Probing the magnetospheric accretion region of the young system DoAr 44 using VLTI/GRAVITY</dc:title>
<dc:type>info:eu-repo/semantics/conferencePoster</dc:type>
<dc:type>poster</dc:type>
</oai_dc:dc>

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