Searching for dust around hyper metal poor stars

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DOIResolve DOI: http://doi.org/10.1088/0004-637X/791/2/98
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TypeArticle
Journal titleThe Astrophysical Journal
ISSN0004-637X
Volume791
Issue2
Article number98
Pages19; # of pages: 9
Subjectdust, extinction; stars: abundances; stars: chemically peculiar; stars: individual; (HE0107-5240)
AbstractWe examine the mid-infrared fluxes and spectral energy distributions for stars with iron abundances [Fe/H] <-5, and other metal-poor stars, to eliminate the possibility that their low metallicities are related to the depletion of elements onto dust grains in the formation of a debris disk. Six out of seven stars examined here show no mid-IR excesses. These non-detections rule out many types of circumstellar disks, e.g., a warm debris disk (T ≤ 290 K), or debris disks with inner radii ≤1 AU, such as those associated with the chemically peculiar post-asymptotic giant branch spectroscopic binaries and RV Tau variables. However, we cannot rule out cooler debris disks, nor those with lower flux ratios to their host stars due to, e.g., a smaller disk mass, a larger inner disk radius, an absence of small grains, or even a multicomponent structure, as often found with the chemically peculiar Lambda Bootis stars. The only exception is HE0107-5240, for which a small mid-IR excess near 10 μm is detected at the 2σ level; if the excess is real and associated with this star, it may indicate the presence of (recent) dust-gas winnowing or a binary system.
Publication date
LanguageEnglish
AffiliationNational Research Council Canada (NRC-CNRC); National Science Infrastructure
Peer reviewedYes
NPARC number21272999
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Record identifierebeb0965-4403-4a7a-aa37-cd90c6bfa797
Record created2014-12-04
Record modified2016-07-18
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