Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Venus transit 2004: Illustrating the capability of exoplanet
  transmission spectroscopy   The transit of Venus in 2004 offered the rare possibility to remotely sense a
well-known planetary atmosphere using ground-based observations for absorption
spectroscopy. Transmission spectra of Venus' atmosphere were obtained in the
near infrared using the Vacuum Tower Telescope (VTT) in Tenerife. Since the
instrument was designed to measure the very bright photosphere of the Sun,
extracting Venus' atmosphere was challenging. CO_2 absorption lines could be
identified in the upper Venus atmosphere. Moreover, the relative abundance of
the three most abundant CO_2 isotopologues could be determined. The
observations resolved Venus' limb, showing Doppler-shifted absorption lines
that are probably caused by high-altitude winds.
  This paper illustrates the ability of ground-based measurements to examine
atmospheric constituents of a terrestrial planet atmosphere which might be
applied in future to terrestrial extrasolar planets.

8
The categories of this paper are: hep-ex
18
The categories of this paper are: econ
24
The categories of this paper are: dg-ga
11
The categories of this paper are: hep-lat
22
The categories of this paper are: chao-dyn
16
The categories of this paper are: stat
31
The categories of this paper are: ao-sci
4
The categories of this paper are: cond-mat
21
The categories of this paper are: adap-org
29
The categories of this paper are: funct-an
25
The categories of this paper are: patt-sol
20
The categories of this paper are: acc-phys
17
The categories of this paper are: q-fin
14
The categories of this paper are: math-ph
0
The categories of this paper are: hep-ph
19
The categories of this paper are: eess