T Dwarf Variability
Abstract
We are proposing to use IRAC to conduct a variability study of seven T dwarfs covering a variety of mid- to late-T dwarf spectral sub-types to assess the amplitude of variability over time scales of days, weeks, months, and years. This study of T dwarf variability in the mid-IR will address three questions: (1) what is the amplitude of variability seen for T dwarfs across a wide variety of temperatures?, (2) what is the time scale of the variability (i.e. is it primarily rotationally modulated (hours)) or do longer time scales (weeks, months, years) related to slower atmospheric changes dominate?, and (3) how much of the observed scatter in T dwarf colors, as observed by IRAC, could be due to variability? Ultimately we hope to determine whether T dwarfs have relatively featureless atmospheres or have more in common with giant planet atmospheres. The monitoring campaign being proposed here is the first step in determining level of variability that can be seen in the T dwarfs in the mid-IR as a part of evaluating the feasibility of future long-term monitoring of these objects with IRAC.
- Publication:
-
Spitzer Proposal
- Pub Date:
- May 2006
- Bibcode:
- 2006sptz.prop30179F