Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Interstellar Comet 2I/Borisov exhibits a structure similar to native
  Solar System comets   We processed images taken with the Hubble Space Telescope (HST) to
investigate any morphological features in the inner coma suggestive of a
peculiar activity on the nucleus of the interstellar comet 2I/Borisov. The coma
shows an evident elongation, in the position angle (PA) ~0-180d direction,
which appears related to the presence of a jet originating from a single active
source on the nucleus. A counterpart of this jet directed towards PA ~10d was
detected through analysis of the changes of the inner coma morphology on HST
images taken in different dates and processed with different filters. These
findings indicate that the nucleus is probably rotating with a spin axis
projected near the plane of the sky and oriented at PA ~100d-280d, and that the
active source is lying in a near-equatorial position. Subsequent observations
of HST allowed us to determine the direction of the spin axis at
RA=17h20m+/-15d and Dec = -35d+\-10d.

15
The categories of this paper are: nucl-ex
2
The categories of this paper are: math
21
The categories of this paper are: adap-org
33
The categories of this paper are: plasm-ph
24
The categories of this paper are: dg-ga
26
The categories of this paper are: bayes-an
14
The categories of this paper are: math-ph
36
The categories of this paper are: cmp-lg
19
The categories of this paper are: eess
13
The categories of this paper are: quant-ph
32
The categories of this paper are: atom-ph
27
The categories of this paper are: comp-gas
34
The categories of this paper are: chem-ph
29
The categories of this paper are: funct-an
23
The categories of this paper are: solv-int
0
The categories of this paper are: hep-ph