Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Investigating The Possible Anomaly Between Nebular and Stellar Oxygen
  Abundances in the Dwarf Irregular Galaxy WLM   We obtained new optical spectra of 13 H II regions in WLM with EFOSC2; oxygen
abundances are derived for nine H II regions. The temperature-sensitive [O III]
4363 emission line was measured in two bright H II regions HM7 and HM9. The
direct oxygen abundances for HM7 and HM9 are 12+log(O/H) = 7.72 +/- 0.04 and
7.91 +/- 0.04, respectively. We adopt a mean oxygen abundance of 12+log(O/H) =
7.83 +/- 0.06. This corresponds to [O/H] = -0.83 dex, or 15% of the solar
value. In H II regions where [O III] 4363 was not measured, oxygen abundances
derived with bright-line methods are in general agreement with direct values of
the oxygen abundance to an accuracy of about 0.2 dex. In general, the present
measurements show that the H II region oxygen abundances agree with previous
values in the literature. The nebular oxygen abundances are marginally
consistent with the mean stellar magnesium abundance ([Mg/H] = -0.62). However,
there is still a 0.62 dex discrepancy in oxygen abundance between the nebular
result and the A-type supergiant star WLM15 ([O/H] = -0.21). Non-zero reddening
values derived from Balmer line ratios were found in H II regions near a second
H I peak. There may be a connection between the location of the second H I
peak, regions of higher extinction, and the position of WLM15 on the eastern
side of the galaxy.

36
The categories of this paper are: cmp-lg
1
The categories of this paper are: cs
5
The categories of this paper are: gr-qc
14
The categories of this paper are: math-ph
25
The categories of this paper are: patt-sol
15
The categories of this paper are: nucl-ex
19
The categories of this paper are: eess
3
The categories of this paper are: physics
2
The categories of this paper are: math
30
The categories of this paper are: q-alg
32
The categories of this paper are: atom-ph
4
The categories of this paper are: cond-mat
28
The categories of this paper are: alg-geom
26
The categories of this paper are: bayes-an
9
The categories of this paper are: nlin
16
The categories of this paper are: stat