Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The spatial distribution of O-B5 stars in the solar neighborhood as
  measured by Hipparcos   We have developed a method to calculate the fundamental parameters of the
vertical structure of the Galaxy in the solar neighborhood from trigonometric
parallaxes alone. The method takes into account Lutz-Kelker-type biases in a
self-consistent way and has been applied to a sample of O-B5 stars obtained
from the Hipparcos catalog. We find that the Sun is located 24.2 +/- 1.7
(random) +/- 0.4 (systematic) pc above the galactic plane and that the disk
O-B5 stellar population is distributed with a scale height of 34.2 +/- 0.8
(random) +/- 2.5 (systematic) pc and an integrated surface density of (1.62 +/-
0.04 (random) +/- 0.14 (systematic)) 10^{-3} stars pc^{-2}. A halo component is
also detected in the distribution and constitutes at least ~5% of the total
O-B5 population. The O-B5 stellar population within ~100 pc of the Sun has an
anomalous spatial distribution, with a less-than-average number density. This
local disturbance is probably associated with the expansion of Gould's belt.

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The categories of this paper are: nlin
15
The categories of this paper are: nucl-ex
2
The categories of this paper are: math
29
The categories of this paper are: funct-an
27
The categories of this paper are: comp-gas
32
The categories of this paper are: atom-ph
24
The categories of this paper are: dg-ga
0
The categories of this paper are: hep-ph
17
The categories of this paper are: q-fin
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The categories of this paper are: supr-con
35
The categories of this paper are: mtrl-th
18
The categories of this paper are: econ
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The categories of this paper are: hep-th
20
The categories of this paper are: acc-phys
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The categories of this paper are: bayes-an
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The categories of this paper are: adap-org