Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Hyperfine splitting of [Al VI]3.66um and the Al isotopic ratio in
  NGC6302   The core of planetary nebula NGC 6302 is filled with high-excitation
photoionised gas at low expansion velocities. It represents a unique
astrophysical situation in which to search for hyperfine structure (HFS) in
coronal emission lines from highly ionised species. HFS is otherwise blended by
thermal or velocity broadening. Spectra containing [AlVI]~3.66um 3P2-3P1,
obtained with Phoenix on Gemini-South at resolving powers of up to 75000,
resolve the line into five hyperfine components separated by 20 to 60km/s due
to the coupling of the I=5/2 nuclear spin of 27Al with the total electronic
angular momentum J. 26Al has a different nuclear spin of I=5, and a different
HFS, which allows us to place a 3sigma upper limit on the 26Al/27Al abundance
ratio of 1/33. We measure the HFS magnetic-dipole coupling constants for
[AlVI], and provide the first estimates of the electric-quadrupole HFS coupling
constants obtained through astronomical observations of an atomic transition.

28
The categories of this paper are: alg-geom
26
The categories of this paper are: bayes-an
4
The categories of this paper are: cond-mat
23
The categories of this paper are: solv-int
19
The categories of this paper are: eess
37
The categories of this paper are: supr-con
1
The categories of this paper are: cs
22
The categories of this paper are: chao-dyn
15
The categories of this paper are: nucl-ex
25
The categories of this paper are: patt-sol
20
The categories of this paper are: acc-phys
7
The categories of this paper are: hep-th
29
The categories of this paper are: funct-an
36
The categories of this paper are: cmp-lg
10
The categories of this paper are: q-bio
12
The categories of this paper are: nucl-th