Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Dust and Polycyclic Aromatic Hydrocarbon in the HD 34700 Debris Disk   The debris disk around the Vega-type star HD 34700 is detected in dust
thermal emission from the near infrared (IR) to millimeter (mm) and submm
wavelength range. Also detected is a distinct set of emission features at 3.3,
6.2, 7.7, 8.6, 11.3 and 12.7 $\mu$m, which are commonly attributed to
polycyclic aromatic hydrocarbon (PAH) molecules. We model the observed dust IR
spectral energy distribution (SED) and PAH emission features of the HD 34700
disk in terms of porous dust and astronomical-PAHs. Porous dust together with a
mixture of neutral and ionized PAHs closely explains the dust IR SED and PAH
emission features observed in the HD 34700 disk. Due to the stellar radiation
pressure and Poynting-Robertson drag together with the photodissociation of
PAHs, substantial removal of dust and PAHs has occurred in the disk, and
continuous replenishment of these materials is required to maintain their
current abundances. This implies that these materials are not primitive but
secondary products probably originating from mutual collisions among
planetesimals, asteroids, and comets.

32
The categories of this paper are: atom-ph
34
The categories of this paper are: chem-ph
11
The categories of this paper are: hep-lat
35
The categories of this paper are: mtrl-th
37
The categories of this paper are: supr-con
10
The categories of this paper are: q-bio
25
The categories of this paper are: patt-sol
36
The categories of this paper are: cmp-lg
5
The categories of this paper are: gr-qc
33
The categories of this paper are: plasm-ph
2
The categories of this paper are: math
1
The categories of this paper are: cs
26
The categories of this paper are: bayes-an
12
The categories of this paper are: nucl-th
29
The categories of this paper are: funct-an
9
The categories of this paper are: nlin