Elemental abundance studies of CP Stars. The silicon stars HD 87240 and HD 96729

 

C. Saffe,^1,3 H. Levato,^2,4 and Z. López-García^2,4

 

¹ Observatorio Astronómico de Córdoba, Laprida 854, 5000 Córdoba, Argentina. On a fellowship from CONICET, Argentina (saffe@oac.uncor.edu).

² Complejo Astronómico El Leoncito, C.C. 467, 5400, San Juan, Argentina.

³ On a fellowship from CONICET, Argentina.

⁴ Members of the Carrera del Investigador Científico, CONICET, Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina. (hlevato@casleo.gov.ar; zlgarcia@casleo.gov.ar).

 

Received 2005 April 6
Accepted 2005 May 3

 

RESUMEN

En este trabajo se comparan abundancias elementales de estrellas Ap de Si de campo y pertenecientes a cúmulos abiertos. En particular, se presenta un análisis de las estrellas Ap de Si HD 87240 y HD 96729, utilizando modelos de atmósferas de ATLAS9 y material observacional tomado con el espectrógrafo echelle REOSC, adosado al telescopio de 2.15 m Jorge Sahade de CASLEO. Estas estrellas químicamente peculiares (CP) pertenecen a los cúmulos abiertos australes NGC 3114 y NGC 3532, respectivamente. Para HD 87240 y HD 96729, C es mayormente solar, Mg y S son ligeramente deficientes, Si y Ca son sobreabundantes por factores entre 1-10. Los elementos más pesados son todos sobreabundantes, TiCrFe por factores de ~ 10, SrYZr por factores entre 100-1000 y tierras raras por factores de ~ 1000 o más.

 

ABSTRACT

We compared elemental abundances of field and open cluster Ap Si stars. In particular, an analysis of the Ap Si stars HD 87240 and HD 96729 is presented using an ATLAS9 model atmosphere and observational material taken with a REOSC echelle spectrograph attached to the Jorge Sahade 2.15 m telescope at CASLEO. These chemically peculiar (CP) stars belong to the southern hemisphere open clusters NGC 3114 and NGC 3532, respectively. For HD 87240 and HD 96729, C is mostly solar, Mg and S are slightly underabundant, Si and Ca are overabundant by factors between 1-10. Heavier elements are all overabundant, TiCrFe by factors of ~ 10, SrYZr by factors between 100-1000 and rare earths by factors of ~ 1000 or more.

Key Words: Stars: Chemically peculiar — Stars: Individual: HD 87240 — Stars: Individual: HD 96729.

 

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ACKNOWLEDGMENTS

This work was partially supported through a grant from the Consejo Nacional de Investigaciones Científicas y Técnicas, República Argentina PIP 4279. ZLG acknowledges partial support by grants from the FONCYT, number 03-1505 and from CICITCA, UNSJ. The authors acknowledge the use of the CCD and data reduction acquisition system supported by US NSF Grant AST 90-15827 to R. M. Rich. The authors thank Drs. R. L. Kurucz and I. Hubeny for making their codes available to them.

 

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