Earth Planets Space, Vol. 65 (No. 10), pp. 1127-1132, 2013
Jian Gao1, Aigen Li2, and B. W. Jiang1
1Department of Astronomy, Beijing Normal University, Beijing 100875, China
2Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211, USA
(Received December 26, 2012; Revised May 24, 2013; Accepted May 29, 2013; Online published October 24, 2013)
We model the ∼1-19μm infrared (IR) extinction curve
toward the Galactic Center (GC) in terms of
the standard silicate-graphite interstellar dust model.
The grains are taken to have a power law size distribution
with an exponential decay above some size.
The best-fit model for the GC IR extinction constrains
the visual extinction to be AV ∼ 38-42 mag.
The limitation of the model, i.e., its difficulty in
both the steep ∼1-3 μm near-IR extinction
and the flat ∼3-8 μm mid-IR extinction
We argue that this difficulty could be alleviated by attributing
the extinction toward the GC to a combination of dust in different
environments: dust in diffuse regions (characterized by small RV
and steep near-IR extinction), and dust in dense regions (characterized
by large RV and flat UV extinction).
Key words: ISM: dust, extinction - infrared: ISM - Galaxy: center.