High-fidelity Imaging of the Inner AU Mic Debris Disk: Evidence of Differential Wind Sculpting?
AuthorWisniewski, John P.
Kowalski, Adam F.
Davenport, James R. A.
Grady, Carol A.
Lawson, Kellen D.
Debes, John H.
Henning, Thomas K.
Hines, Dean C.
Kuchner, Marc J.
Stark, Christopher C.
AffiliationUniv Arizona, Steward Observ
Univ Arizona, Dept Astron
MetadataShow full item record
PublisherIOP PUBLISHING LTD
CitationWisniewski, J. P., Kowalski, A. F., Davenport, J. R., Schneider, G., Grady, C. A., Hebb, L., ... & Debes, J. H. (2019). High-fidelity Imaging of the Inner AU Mic Debris Disk: Evidence of Differential Wind Sculpting?. The Astrophysical Journal Letters, 883(1), L8.
JournalASTROPHYSICAL JOURNAL LETTERS
Rights© 2019. The American Astronomical Society.
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 email@example.com.
AbstractWe present new high-fidelity optical coronagraphic imagery of the inner similar to 50 au of AU Mic's edge-on debris disk using the BAR5 occulter of the Hubble Space Telescope Imaging Spectrograph (HST/STIS) obtained on 2018 July 26-27. This new imagery reveals that "feature A," residing at a projected stellocentric separation of 14.2 au on the southeast side of the disk, exhibits an apparent "loop-like" morphology at the time of our observations. The loop has a projected width of 1.5 au and rises 2.3 au above the disk midplane. We also explored Transiting Exoplanet Survey Satellite photometric observations of AU Mic that are consistent with evidence of two starspot complexes in the system. The likely co-alignment of the stellar and disk rotational axes breaks degeneracies in detailed spot modeling, indicating that AU Mic's projected magnetic field axis is offset from its rotational axis. We speculate that small grains in AU Mic's disk could be sculpted by a time-dependent wind that is influenced by this offset magnetic field axis, analogous to co-rotating solar interaction regions that sculpt and influence the inner and outer regions of our own Heliosphere. Alternatively, if the observed spot modulation is indicative of a significant misalignment of the stellar and disk rotational axes, we suggest that the disk could still be sculpted by the differential equatorial versus polar wind that it sees with every stellar rotation.
VersionFinal published version
SponsorsSpace Telescope Science Institute (STScI) [GO-15219]