Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: TESS observations of Be stars: a new interpretation   Light curves of 57 classical Be stars in TESS sectors 1 - 15 are examined. In
most Be stars, the periodogram shows groups at a fundamental and one or more
harmonics, which we attribute to rotation. In about 40 percent of the stars,
the group is just a single narrow or slightly broadened peak. In about 30
percent, it consists of a multiple, closely spaced peaks. These groups can be
interpreted as non-coherent variations most likely associated with photospheric
gas clouds. Approximate rotational frequencies for about 75 percent of the
stars can be derived. Comparison with the projected rotational velocities shows
that the photometric frequency is consistent with rotation. The first harmonic
plays a prominent role in many Be stars and manifests itself in either
single-wave or double-wave light curves. The reduction in amplitude of beta Cep
pulsations in a few Be stars during an outburst and their subsequent recovery
is most likely an obscuration effect. Other instances of possible obscuration
of the photosphere are suspected. A simple model, which attempts to explain
these observations and other general properties of Be stars, is proposed.

21
The categories of this paper are: adap-org
5
The categories of this paper are: gr-qc
2
The categories of this paper are: math
3
The categories of this paper are: physics
23
The categories of this paper are: solv-int
12
The categories of this paper are: nucl-th
13
The categories of this paper are: quant-ph
19
The categories of this paper are: eess
33
The categories of this paper are: plasm-ph
20
The categories of this paper are: acc-phys
7
The categories of this paper are: hep-th
25
The categories of this paper are: patt-sol
28
The categories of this paper are: alg-geom
22
The categories of this paper are: chao-dyn
36
The categories of this paper are: cmp-lg
32
The categories of this paper are: atom-ph