Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Observational evidence for a correlation between macroturbulent
  broadening and line-profile variations in OB Supergiants   The spectra of O and B supergiants are known to be affected by a significant
form of extra line broadening (usually referred to as macroturbulence) in
addition to that produced by stellar rotation. Recent analyses of high
resolution spectra have shown that the interpretation of this line broadening
as a consequence of large scale turbulent motions would imply highly supersonic
velocity fields in photospheric regions, making this scenario quite improbable.
Stellar oscillations have been proposed as a likely alternative explanation. As
part of a long term observational project, we are investigating the
macroturbulent broadening in O and B supergiants and its possible connection
with spectroscopic variability phenomena and stellar oscillations. In this
letter, we present the first encouraging results of our project, namely firm
observational evidence for a strong correlation between the extra broadening
and photospheric line-profile variations in a sample of 13 supergiants with
spectral types ranging from O9.5 to B8.

8
The categories of this paper are: hep-ex
28
The categories of this paper are: alg-geom
33
The categories of this paper are: plasm-ph
1
The categories of this paper are: cs
25
The categories of this paper are: patt-sol
16
The categories of this paper are: stat
32
The categories of this paper are: atom-ph
35
The categories of this paper are: mtrl-th
11
The categories of this paper are: hep-lat
10
The categories of this paper are: q-bio
29
The categories of this paper are: funct-an
0
The categories of this paper are: hep-ph
9
The categories of this paper are: nlin
14
The categories of this paper are: math-ph
18
The categories of this paper are: econ
19
The categories of this paper are: eess