The Discovery of lambda Bootis Stars -- The Southern Survey II

Abstract

The $\lambda$ Boo stars are chemically peculiar A-type stars whose abundance anomalies are associated with the accretion of metal-poor material. We searched for $\lambda$ Boo stars in the southern hemisphere in a targeted spectroscopic survey of metal-weak and emission-line stars. Obtaining spectra for 308 stars and classifying them on the MK system, we found or co-discovered 24 new $\lambda$ Boo stars. We also revised the classifications of 11 known $\lambda$ Boo stars, one of which turned out to be a chemically normal rapid rotator. We show that stars previously classified in the literature as blue horizontal branch stars or emission-line A stars have a high probability of being $\lambda$ Boo stars, although this conclusion is based on small-number statistics. Using WISE infrared fluxes, we searched our targets for infrared excesses that might be attributable to protoplanetary or debris discs as the source of the accreted material. Of the 34 $\lambda$ Boo stars in our sample, 21 at various main-sequence ages have infrared excesses, confirming that not all $\lambda$ Boo stars are young.

Accepted for publication in MNRAS. Figures do not have heavy reliance on colour. Online data will be hosted with the journal / Vizier@CDS

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Cited by in corpus (7)

• A precise asteroseismic age and metallicity for HD 139614: a pre-main-sequence star with a protoplanetary disc in Upper-Centaurus Lupus
• A Novel Method to Estimate the FUV Flux and a Catalogue for Star-Hosting Discs in Nearby Star-Forming Regions
• An interferometric study of B star multiplicity
• Testing the accretion scenario of lambda Boo stars
• Searching for lambda Boo stars in binary systems
• Discovery of lambda Boo stars in open clusters
• Drifters on the edge of town: $\lambda$ Boötis stars in clusters