NOAO >   Observing Info >   Approved Programs >   2007B-0291

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Proposal Information for 2007B-0291


PI: Joleen Miller, University of Virginia, jkm9n@virginia.edu
Address: Department of Astronomy, P.O. Box 400325, Charlottesville, VA 22904-4325, USA

CoI: Steven Majewski, University of Virginia
CoI: Verne Smith, NOAO
CoI: Robert Rood, University of Virginia
CoI: Katia Cunha, NOAO
CoI: Richard Patterson, University of Virginia
CoI: Dmitry Bizyaev, NOAO

Title: Testing the Planet Absorption Paradigm for Rapidly Rotating K Giant Stars

Abstract: Two competing mechanisms proposed to account for the anomalously large rotational velocities of single K giant stars are angular momentum dredge-up via a deepening of the convective layer and accretion of a low- mass companion such as a giant planet or brown dwarf. Both theories are capable of explaining the excess of ^7Li often seen in giant star rapid rotators; however, each mechanism should leave distinct chemical fingerprints in other elements. For example, it has been shown that stars with planet systems often show a trend of increasing abundances for increasing element condensation temperature, as might be expected for the ingestion of chemically-fractionated material. It is also expected that ingestion of large planets will alter the stellar ^12C/^13C ratio by a perceptible degree. We intend to measure the stellar parameters, abundances of elements from lithium to europium, and the ratio of ^12C/^13C among a sample of rapid rotators we have discovered to make four separate chemical tests of the planet ingestion model for giant stars. Because planets are known to exist commonly as systems, our control sample will include K giants with at least one known planetary companion, as well as non-rapid rotators spanning a similar giant star population. This research may open new avenues for studying, at least statistically, planets around evolved stars.


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