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Chemical abundances from inversions of stellar spectra: Analysis of solar-type stars with homogeneous and static model atmospheres

Allende Prieto, Carlos; Barklem, Paul S; Asplund, Martin; Ruiz Cobo, Basilio

Description

Spectra of late-type stars are usually analyzed with static model atmospheres in local thermodynamic equilibrium (LTE) and a homogeneous plane-parallel or spherically symmetric geometry. The energy balance requires particular attention, as two elements that are particularly difficult to model play an important role : line blanketing and convection. Inversion techniques are able to bypass the difficulties of a detailed description of the energy balance. Assuming that the atmosphere is in...[Show more]

dc.contributor.authorAllende Prieto, Carlos
dc.contributor.authorBarklem, Paul S
dc.contributor.authorAsplund, Martin
dc.contributor.authorRuiz Cobo, Basilio
dc.date.accessioned2002-12-09
dc.date.accessioned2004-05-19T04:47:42Z
dc.date.accessioned2011-01-05T08:30:00Z
dc.date.available2004-05-19T04:47:42Z
dc.date.available2011-01-05T08:30:00Z
dc.date.created2001
dc.identifier.urihttp://hdl.handle.net/1885/40057
dc.identifier.urihttp://digitalcollections.anu.edu.au/handle/1885/40057
dc.description.abstractSpectra of late-type stars are usually analyzed with static model atmospheres in local thermodynamic equilibrium (LTE) and a homogeneous plane-parallel or spherically symmetric geometry. The energy balance requires particular attention, as two elements that are particularly difficult to model play an important role : line blanketing and convection. Inversion techniques are able to bypass the difficulties of a detailed description of the energy balance. Assuming that the atmosphere is in hydrostatic equilibrium and LTE, it is possible to constrain its structure from spectroscopic observations. Among the most serious approximations still implicit in the method is a static and homogeneous geometry. In this paper, we take advantage of a realistic three-dimensional radiative hydrodynamical simulation of the solar surface to check the systematic errors incurred by an inversion assuming a plane-parallel horizontally-homogeneous atmosphere. The thermal structure recovered resembles the spatial and time average of the three-dimensional atmosphere. Furthermore, the abundances retrieved are typically within 10% (0.04 dex) of the abundances used to construct the simulation. The application to a fairly complete data set from the solar spectrum provides further confidence in previous analyses of the solar composition. There is only a narrow range of one-dimensional thermal structures able to fit the absorption lines in the spectrum of the Sun. With our carefully selected data set, random errors are about a factor of 2 smaller than systematic errors. A small number of strong metal lines can provide very reliable results. We foresee no major difficulties in applying the technique to other similar stars, and obtaining similar accuracies, using spectra with λ/δλ ~ 5 x 10(4) and a signal-to-noise ratio as low as 30.
dc.format.extent1035764 bytes
dc.format.mimetypeapplication/pdf
dc.language.isoen_AU
dc.publisherThe American Astronomical Society
dc.subjectline: formation
dc.subjectline: profiles
dc.subjectmethods: data analysis
dc.subjectstars: abundances
dc.subjectsun: abundances
dc.subjectsun: photosphere
dc.titleChemical abundances from inversions of stellar spectra: Analysis of solar-type stars with homogeneous and static model atmospheres
dc.typeJournal article
local.description.refereedyes
local.identifier.citationmonthsep
local.identifier.citationpages830-851
local.identifier.citationpublicationThe Astrophysical Journal
local.identifier.citationvolume558
local.identifier.citationyear2001
local.identifier.eprintid734
local.rights.ispublishedyes
dc.date.issued2001
CollectionsANU Research Publications

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