Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Searching for molecular hydrogen mid-infrared emission in the
  circumstellar environments of Herbig Be stars   Context: Molecular hydrogen (H2) is the most abundant molecule in the
circumstellar (CS) environments of young stars, and is a key element in giant
planet formation. The measurement of the H2 content provides the most direct
probe of the total amount of CS gas, especially in the inner warm
planet-forming regions of the disks.
  Aims: Most Herbig Be stars (HBes) are distant from the Sun and their nature
and evolution are still debated. We therefore conducted mid-infrared
observations of H2 as a tracer of warm gas around HBes known to have gas-rich
CS environments.
  Methods: We report a search for the H2 S(1) emission line at 17.0348 microns
in the CS environments of 5 HBes with the high resolution spectroscopic mode of
VISIR (ESO VLT Imager and Spectrometer for the mid-InfraRed).
  Results: No source shows evidence for H2 emission at 17.0348 microns.
Stringent 3sigma upper limits on the integrated line fluxes are derived.
Depending on the adopted temperature, limits on column densities and masses of
warm gas are also estimated. These non-detections constrain the amount of warm
(>150 K) gas in the immediate CS environments of our target stars to be less
than 1-10 Jupiter masses.

29
The categories of this paper are: funct-an
35
The categories of this paper are: mtrl-th
20
The categories of this paper are: acc-phys
13
The categories of this paper are: quant-ph
32
The categories of this paper are: atom-ph
30
The categories of this paper are: q-alg
26
The categories of this paper are: bayes-an
17
The categories of this paper are: q-fin
2
The categories of this paper are: math
34
The categories of this paper are: chem-ph
28
The categories of this paper are: alg-geom
31
The categories of this paper are: ao-sci
18
The categories of this paper are: econ
16
The categories of this paper are: stat
15
The categories of this paper are: nucl-ex
33
The categories of this paper are: plasm-ph