English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

We present a Spitzer IRS study of variability in 14 T Tauri stars in theTaurus and Chamaeleon star-forming regions. The sample is composed oftransitional and pre-transitional objects which contain holes and gaps in theirdisks. We detect variability between 5-38 microns in all but two of our objectson timescales of 2-3 years. Most of the variability observed can be classifiedas seesaw behavior, whereby the emission at shorter wavelengths variesinversely with the emission at longer wavelengths. For many of the objects wecan reasonably reproduce the observed variability using irradiated disk models,particularly by changing the height of the inner disk wall by ~20%. When theinner wall is taller, the emission at the shorter wavelengths is higher sincethe inner wall dominates the emission at 2-8 microns. The taller inner wallcasts a larger shadow on the outer disk wall, leading to less emission atwavelengths beyond 20 microns where the outer wall dominates. We discuss howthe possible presence of planets in these disks could lead to warps which causechanges in the height of the inner wall. We also find that crystallinesilicates are common in the outer disks of our objects and that in the fourdisks in the sample with the most crystalline silicates, variability ontimescales of 1 week is present. In addition to explaining the infraredvariability described above, planets can create shocks and collisions which cancrystallize the dust and lead to short timescale variability.

A Spitzer IRS Study of Infrared Variability in Transitional and Pre-Transitional Disks around T Tauri Stars