Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The X-ray off-state of the supersoft source CAL 83 and its
  interpretation   We consider simultaneous optical data obtained during the recent X-ray
turn-off of CAL83. Combining the optical behaviour with the observed X-ray
decay time, we show that a model of cessation of steady nuclear burning is
viable if the white dwarf is massive. Our model provides a natural explanation
for the subsequent return of the supersoft X-ray emission.

29
The categories of this paper are: funct-an
0
The categories of this paper are: hep-ph
32
The categories of this paper are: atom-ph
15
The categories of this paper are: nucl-ex
35
The categories of this paper are: mtrl-th
17
The categories of this paper are: q-fin
16
The categories of this paper are: stat
26
The categories of this paper are: bayes-an
22
The categories of this paper are: chao-dyn
20
The categories of this paper are: acc-phys
3
The categories of this paper are: physics
30
The categories of this paper are: q-alg
19
The categories of this paper are: eess
8
The categories of this paper are: hep-ex
33
The categories of this paper are: plasm-ph
18
The categories of this paper are: econ