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The Surprising Evolution of the Shadow on the TW Hya Disk*

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posted on 2023-05-22, 10:33 authored by John Debes, Rebecca Nealon, Richard Alexander, Alycia J Weinberger, Schuyler Grace Wolff, Dean Hines, Joel Kastner, Hannah Jang-Condell, Christophe Pinte, Peter Plavchan, Laurent Pueyo

We report new total-intensity visible-light high-contrast imaging of the TW Hya disk taken with the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope. This represents the first published images of the disk with STIS since 2016, when a moving shadow on the disk surface was reported. We continue to see the shadow moving in a counterclockwise fashion, but in these new images the shadow has evolved into two separate shadows, implying a change in behavior for the occulting structure. Based on radiative-transfer models of optically thick disk structures casting shadows, we infer that a plausible explanation for the change is that there are now two misaligned components of the inner disk. The first of these disks is located between 5 and 6 au with an inclination of 5.5° and position angle (PA) of 170°, and the second between 6 and 7 au with an inclination of 7° and PA of 50°. Finally, we speculate on the implications of the new shadow structure and determine that additional observations are needed to disentangle the nature of TW Hya's inner-disk architecture.

History

Author affiliation

School of Physics & Astronomy, University of Leicester

Version

  • VoR (Version of Record)

Published in

The Astrophysical Journal

Volume

948

Issue

1

Pagination

36

Publisher

American Astronomical Society

issn

0004-637X

eissn

1538-4357

Copyright date

2023

Available date

2023-05-22

Language

en

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