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arXiv · 1710.05930

iota Horologii is unlikely to be an evaporated Hyades star

I. Ramirez·D. Yong·E. Gutierrez·M. Endl·D. L. Lambert·J. -D. Do Nascimento Jr
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Abstract

We present a high-precision chemical analysis of iota Horologii, a planet-host field star thought to have formed in the Hyades. Elements with atomic number 6<=Z<=30 have abundances that are in excellent agreement with those of the cluster within the +/-0.01 dex (or ~2%) precision errors. Heavier elements show a range of abundances such that about half of the Z>30 species analyzed are consistent with those of the Hyades, while the other half are marginally enhanced by 0.03+/-0.01 dex (~7+/-2%). The lithium abundance, A(Li), is very low compared to the well-defined A(Li)-Teff relation of the cluster. For its Teff, iota Horologii's lithium content is about half the Hyades'. Attributing the enhanced lithium depletion to the planet would require a peculiar rotation rate, which we are unable to confirm. Our analysis of the star's chromospheric activity suggests Prot=5d, which is significantly shorter than previously reported. Models of Galactic orbits place iota Horologii hundreds of parsecs away from the Hyades cluster at formation. Thus, we find the claim of a shared birthplace very difficult to justify.

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I. Ramirez, D. Yong, E. Gutierrez, M. Endl, D. L. Lambert, J. -D. Do Nascimento Jr. 2017-10-16. iota Horologii is unlikely to be an evaporated Hyades star. https://doi.org/10.3847/1538-4357/aa9437

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