Thumbnail
Access Restriction
Open

Author Nagel, E. ♦ Flaherty, K. M. ♦ Muzerolle, J.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword ASTROPHYSICS, COSMOLOGY AND ASTRONOMY ♦ COMPARATIVE EVALUATIONS ♦ CORRELATIONS ♦ COSMIC DUST ♦ FLUCTUATIONS ♦ HOT SPOTS ♦ ILLUMINANCE ♦ LUMINOSITY ♦ MASS ♦ PHOTOMETRY ♦ PROTOPLANETS ♦ STAR ACCRETION ♦ STAR CLUSTERS ♦ STARS ♦ SUBLIMATION
Abstract We study the changes in the sublimation wall structure due to variable illumination of a stellar hot spot on the dusty surroundings of a young star. The model includes the settling of large grains toward the disk midplane and the effect of the vertical density profile on the shaping of the sublimation wall. From a survey of objects in the young cluster IC 348, we extract three objects (LRLL 32, 40, and 63) that present typical variability in the [3.6] and [4.5] IRAC bands. We use the Spitzer photometry and ground-based 2–5 μm spectra for comparison with the models. Even though there is a correlation between accretion luminosity and dust emission based on the observations, we conclude from the modeling that the systems with lower mass accretion rates (LRLL 32 and 63) cannot be explained simply by a variable hot spot illuminating a sublimation wall. The observed variability amplitude for LRLL 40 (the system with the largest value of the mass accretion rate) can be obtained using the mechanism presented here. When considering a wide range of hot spot sizes and temperatures, the models can reproduce the infrared fluctuations seen in recent surveys, but only with accretion rate fluctuations that are orders of magnitude larger than is typically observed. These results highlight the relevance of accretion as a variability mechanism as well as its limitations in producing the full extent of the observed infrared variability.
ISSN 0004637X
Educational Use Research
Learning Resource Type Article
Publisher Date 2015-08-01
Publisher Place United States
Journal Astrophysical Journal
Volume Number 808
Issue Number 2


Open content in new tab

   Open content in new tab