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dc.contributor.author Pereira, C. B.
dc.contributor.author Baella, Nobar
dc.contributor.author Drake, N. A.
dc.contributor.author Miranda, L. F.
dc.contributor.author Roig, F.
dc.date.accessioned 2018-08-03T16:56:34Z
dc.date.available 2018-08-03T16:56:34Z
dc.date.issued 2017-05-23
dc.identifier.govdoc index-oti2018 (NB)
dc.identifier.issn 0004637X
dc.identifier.uri http://repositorio.igp.gob.pe/handle/IGP/2238
dc.description En: The Astrophysical Journal, v. 841, n. 50 (May 2017), 20 p. es_ES
dc.description.abstract "We report on the analysis of high-resolution optical spectra of four symbiotic stars: AS 255, MWC 960, RW Hya, and StHα32. We employ the local-thermodynamic-equilibrium model atmospheres of Kurucz and the spectral analysis code MOOG to analyze the spectra. The abundance of barium and carbon was derived using the spectral synthesis technique. The chemical composition of the atmospheres of AS 255 and MWC 960 show that they are metal-poor K giants with metallicities of −1.2 and −1.7 respectively. StHα32 is a CH star and also a lowmetallicity object (−1.4). AS 255 and MWC 960 are yellow symbiotic stars and, like other previously studied yellow symbiotics, are s-process enriched. StHα32, like other CH stars, is also an s-process and carbon-enriched object. RW Hya has a metallicity of −0.64, a value in accordance with previous determinations, and is not s-process enriched. Based on its position in the 2MASS diagram, we suggest that RW Hya is at an intermediate position between yellow symbiotics and classical S-type symbiotics. We also discuss whether the dilution effect was the mechanism responsible for the absence of the s-process elements overabundance in RW Hya. The luminosity obtained for StHα32 is below the luminosity of the asymptotic giant branch (AGB) stars that started helium burning (via thermal pulses) and became self-enriched in neutron-capture elements. Therefore, its abundance peculiarities are due to mass transfer from the previous thermally pulsing AGB star (now the white dwarf) that was overabundant in s-process elements. For the stars AS 255 and MWC 960, the determination of their luminosities was not possible due to uncertainties in their distance and interstellar absorption. AS 255 and MWC 960 have a low galactic latitude and could be bulge stars or members of the inner halo population. The heavy-element abundance distribution of AS 255 and MWC 960 is similar to that of the other yellow symbiotics previously analyzed. Their abundance patterns follow that of the thick disk population for RW Hya and of the halo population for AS 255, MWC 960, and StHα32. We also determined the rotational velocities of these four symbiotic stars and compare our results with those of single field stars." es_ES
dc.format application/pdf es_ES
dc.language.iso eng es_ES
dc.publisher Instituto Geofísico del Perú es_ES
dc.rights info:eu-repo/semantics/restrictedAccess es_ES
dc.rights.uri info:eu-repo/semantics/restrictedAccess es_ES
dc.source Repositorio institucional - IGP es_ES
dc.subject Estrellas es_ES
dc.subject Astrofísica es_ES
dc.subject Estrellas dobles es_ES
dc.subject Binarios de rayos X es_ES
dc.subject Estrellas múltiples es_ES
dc.subject Estrellas variables es_ES
dc.title High-resolution optical spectroscopic observations of four symbiotic stars: AS 255, MWC 960, RW Hya, and StHα 32. es_ES
dc.type info:eu-repo/semantics/article es_ES
dc.subject.ocde Astronomía es_ES
dc.subject.ocde Ciencias espaciales es_ES
dc.subject.ocde Ciencias del espacio es_ES
dc.subject.ocde Atmósfera es_ES
dc.identifier.journal The Astrophysical Journal es_ES
dc.description.peer-review Por pares es_ES
dc.identifier.doi 10.3847/1538-4357/aa6d78 es_ES

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