Su, Kate Y. L.
Rogers, L. K.
van Lieshout, Rik
Green, Elizabeth M.
Wilson, Thomas G.
Wilson, David J.
Gänsicke, Boris T.
AffiliationUniv Arizona, Steward Observ
minor planets, asteroids: general
stars: individual (G29-38, SDSS J122859.93+104032.9)
MetadataShow full item record
PublisherIOP PUBLISHING LTD
CitationSiyi Xu et al 2018 ApJ 866 108
Rights© 2018. 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.
AbstractThe most heavily polluted white dwarfs often show excess infrared radiation from circumstellar dust disks, which are modeled as a result of tidal disruption of extrasolar minor planets. Interaction of dust, gas, and disintegrating objects can all contribute to the dynamical evolution of these dust disks. Here, we report two infrared variable dusty white dwarfs, SDSS. J1228+1040 and G29-38. For SDSS. J1228+1040, compared to the first measurements in 2007, the IRAC [3.6] and [4.5] fluxes decreased by 20% before 2014 to a level also seen in the recent 2018 observations. For G29-38, the infrared flux of the 10 mu m silicate emission feature became 10% stronger between 2004 and 2007, We explore several scenarios that could account for these changes, including tidal disruption events, perturbation from a companion, and runaway accretion. No satisfactory causes are found for the flux drop in SDSS. J1228+1040 due to the limited time coverage. Continuous tidal disruption of small planetesimals could increase the mass of small grains and concurrently change the strength of the 10 mu m feature of G29-38. Dust disks around white dwarfs are actively evolving and we speculate that there could be different mechanisms responsible for the temporal changes of these disks.
VersionFinal published version
SponsorsRoyal Society Dorothy Hodgkin Fellowship; ICM (Iniciativa Cientifica Milenio) via the Nucleo Milenio de Formacion Planetaria grant; Fondecyt ; Science and Technology Facilities Council via an Ernest Rutherford Fellowship [ST/P003850/1]; STFC studentship; European Research Council under the European Union's Seventh Framework Programme (FP/2007-2013)/ERC ; National Aeronautics and Space Administration; Universidad de Valparaiso