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Probing atlas model atmospheres at high spectral resolution. Stellar synthesis and reference template validation
EMANUELE BERTONE TARICCO
MIGUEL Y ROSA MARIA CHAVEZ DAGOSTINO
LINO HECTOR RODRIGUEZ MERINO
Acceso Abierto
Atribución-NoComercial-SinDerivadas
Aims. The fast improvement of spectroscopic observations makes mandatory a strong effort on the theoretical side to better reproduce the spectral energy distribution (SED) of stars at high spectral resolution. In this regard, relying on the Kurucz Atlas/Synthe original codes we computed the Bluered library, consisting of 832 synthetic SED of stars, that cover a large parameter space at very high spectral resolution (R = 500 000) along the 3500−7000 Å wavelength range. Methods. Bluered synthetic spectra have been used to assess in finer detail the intrinsic reliability and the performance limits of the Atlas theoretical framework. The continuum-normalized spectra of the Sun, Arcturus, and Vega, plus a selected list of 45 bright stars with high-quality SEDs from the Prugniel & Soubiran Elodie catalog, form our sample designed to probe the global properties of synthetic spectra across the entire range of H-R parameters. Results. Atlas models display a better fitting performance with increasing stellar temperature. High-resolution spectra of Vega, the Sun, and Arcturus have been reproduced at R = 100 000, respectively, within a 0.7%, 4.5%, and 8.8% relative scatter in residual flux. In all the three cases, the residual flux distribution shows a significant asymmetry (skewness parameter γ = −2.21, −0.98, −0.67, respectively), which neatly confirms an overall “excess” of theoretical line blanketing. For the Sun, this apparent discrepancy is alleviated, but not recovered, by a systematic decrease (−40%) of the line oscillator strengths, log(ɡf ), especially referring to iron transitions. Definitely, a straight “astrophysical” determination of log(ɡf) for each individual atomic transition has to be devised to overcome the problem. By neglecting overblanketing effects in theoretical models when fitting high-resolution continuum-normalized spectra of real stars, we lead to a systematically warmer effective temperature (between +80 and +300 K for the solar fit) and a slightly poorer metal content.
Astronomy and Astrophysics
2008
Artículo
Inglés
Estudiantes
Investigadores
Público en general
Bertone, E., et al., (2008). Probing atlas model atmospheres at high spectral resolution stellar synthesis and reference template validation, Astronomy and Astrophysics, Vol.485(3):823-835
ASTRONOMÍA Y ASTROFÍSICA
Versión aceptada
acceptedVersion - Versión aceptada
Aparece en las colecciones: Artículos de Astrofísica

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