The discovery of lambda Bootis stars - the Southern Survey II

Murphy, Simon J. and Gray, Richard O. and Corbally, Christopher J. and Kuehn, Charles and Bedding, Timothy R. and Killam, Josiah (2020) The discovery of lambda Bootis stars - the Southern Survey II. Monthly Notices of the Royal Astronomical Society, 499 (2). pp. 2701-2713. ISSN 0035-8711

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Abstract

The λ Boo stars are chemically peculiar A-type stars whose abundance anomalies are associated with the accretion of metal-poor material. We searched for λ 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 λ Boo stars. We also revised the classifications of 11 known λ 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 λ 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 λ Boo stars in our sample, 21 at various main-sequence ages have infrared excesses, confirming that not all λ Boo stars are young.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: File reproduced in accordance with the copyright policy of the publisher/author.
Faculty/School / Institute/Centre: No Faculty
Faculty/School / Institute/Centre: No Faculty
Date Deposited: 14 Jul 2022 00:15
Last Modified: 18 Jul 2022 02:04
Uncontrolled Keywords: stars: chemically peculiar; circumstellar matter; stars: early-type; stars: emission-line, Be; stars: evolution; Astrophysics - Solar and Stellar Astrophysics
Fields of Research (2020): 51 PHYSICAL SCIENCES > 5101 Astronomical sciences > 510109 Stellar astronomy and planetary systems
Socio-Economic Objectives (2020): 28 EXPANDING KNOWLEDGE > 2801 Expanding knowledge > 280120 Expanding knowledge in the physical sciences
Identification Number or DOI: https://doi.org/10.1093/mnras/staa2347
URI: http://eprints.usq.edu.au/id/eprint/47921

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