Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: ATLAS vs. NextGen model atmospheres: a combined analysis of synthetic
  spectral energy distributions   We carried out a critical appraisal of the two theoretical models, Kurucz'
ATLAS9 and PHOENIX/NextGen, for stellar atmosphere synthesis. Our tests relied
on the theoretical fit of SEDs for a sample of 334 target stars along the whole
spectral-type sequence. The best-fitting physical parameters of stars allowed a
calibration of the temperature and bolometric scale. The main conclusions of
our analysis are: i) the fitting accuracy of both theoretical libraries
drastically degrades at low Teff; ii) comparing with empirical calibrations,
both ATLAS and NextGen fits tend to predict slightly warmer Teff, but ATLAS
provides in general a sensibly better fit; iii) there is a striking tendency of
NextGen to label target stars with an effective temperature and surface gravity
in excess with respect to ATLAS. This is a consequence of some ``degeneracy''
in the solution space, partly induced by the different input physics and
geometry constraints. A different T(\tau) vertical structure of stellar
atmosphere seems also required for NextGen synthetic SEDs in order to better
account for limb-darkening effects in cool stars, as supported by the recent
observations of the EROS BLG2000-5 microlensing event.

23
The categories of this paper are: solv-int
31
The categories of this paper are: ao-sci
2
The categories of this paper are: math
0
The categories of this paper are: hep-ph
28
The categories of this paper are: alg-geom
29
The categories of this paper are: funct-an
30
The categories of this paper are: q-alg
11
The categories of this paper are: hep-lat
4
The categories of this paper are: cond-mat
22
The categories of this paper are: chao-dyn
13
The categories of this paper are: quant-ph
20
The categories of this paper are: acc-phys
14
The categories of this paper are: math-ph
7
The categories of this paper are: hep-th
18
The categories of this paper are: econ
8
The categories of this paper are: hep-ex