L. García1,2 and M. Gómez1
1 Observatorio Astronómico de Córdoba (OAC), Argentina. Laprida 854, X5000GBR Córdoba, Argentina (lucianog@oac.uncor.edu, mercedes@oac.uncor.edu).
2 Visiting Astronomer, Complejo Astronómico El Leoncito (CASLEO) operated under agreement between the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina and the National Universities of La Plata, Córdoba and San Juan.
Received April 1 2014.
Accepted September 2 2014.
RESUMEN
Se presentan mediciones polarimétricas en el óptico de 34 estrellas de secuencia principal con discos de escombros observables desde el hemisferio sur, junto con 54 estrellas sin evidencia de disco. Estas muestras se combinan con una de 109 estrellas del hemisferio norte de la literatura, para obtener dos conjuntos de 51 y 97 estrellas de tipo solar con y sin disco, respectivamente. Los valores de polarización de ambas muestras no resultan estadísticamente diferentes dentro de la precisión alcanzada. Sin embargo, se identifican 9 estrellas (d ≲ 50 pc) con disco que poseen valores de polarización por encima de la media de la muestra con disco y que no reproducen adecuadamente la ley interestelar de Serkowski. Estas estrellas son candidatas a poseer polarización intrínseca. En este caso los discos de escombros de estas estrellas podrían estar poblados por partículas con tamaños de ≈0.1µm.
ABSTRACT
We report optical aperture polarimetry for 34 southern hemisphere main-sequence stars with debris disks, in addition to 54 stars without evidence of disk. These sets of stars are combined with another set of 109 stars from the northern hemisphere, obtained from the literature, to build two samples of 51 and 97 solar-type stars with and without debris disks. The distributions of polarization values for the samples with and without disks show no significant statistical difference, within the precision of our observations. However, we identify a sub-sample of 9 stars (d ≲ 50 pc) with disks that have polarization levels above the median for the sample with disk, and that are not appropriately reproduced by Serkowski's interstellar law. These stars are candidates to have intrinsic polarization. In this case the debris disks in these stars may be populated by small dust with sizes of ≈0.1µm.
Key Words: Kuiper belt: general — stars: solar-type — techniques: polarimetric — zodiacal dust.
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