Chasing Shadows: Rotation of the Azimuthal Asymmetry in the TW Hya Disk
AuthorDebes, John H.
Poteet, Charles A.
Hines, Dean C.
Kastner, Joel H.
Weinberger, A. J.
AffiliationUniv Arizona, Steward Observ
planets and satellites: formation
stars: individual (TW Hya)
MetadataShow full item record
PublisherIOP PUBLISHING LTD
CitationChasing Shadows: Rotation of the Azimuthal Asymmetry in the TW Hya Disk 2017, 835 (2):205 The Astrophysical Journal
JournalThe Astrophysical Journal
Rights© 2017. The American Astronomical Society. All rights reserved.
Collection InformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at firstname.lastname@example.org.
AbstractWe have obtained new images of the protoplanetary disk orbiting TW Hya in visible, total intensity light with the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope (HST), using the newly commissioned BAR5 occulter. These HST/STIS observations achieved an inner working angle of similar to 0."2, or 11.7 au, probing the system at angular radii coincident with recent images of the disk obtained by ALMA and in polarized intensity near-infrared light. By comparing our new STIS images to those taken with STIS in 2000 and with NICMOS in 1998, 2004, and 2005, we demonstrate that TW Hya's azimuthal surface brightness asymmetry moves coherently in position angle. Between 50 au and 141 au we measure a constant angular velocity in the azimuthal brightness asymmetry of 22 degrees.7. 7 yr(-1) in a counterclockwise direction, equivalent to a period of 15.9. yr assuming circular motion. Both the (short) inferred period and lack of radial dependence of the moving shadow pattern are inconsistent with Keplerian rotation at these disk radii. We hypothesize that the asymmetry arises from the fact that the disk interior to 1 au is inclined and precessing owing to a planetary companion, thus partially shadowing the outer disk. Further monitoring of this and other shadows on protoplanetary disks potentially opens a new avenue for indirectly observing the sites of planet formation.
VersionFinal published version
SponsorsNASA [HST-GO-13753, NAS 5-26555]; Space Telescope Science Institute; NASA Exoplanets Program [NNX16AB43G]