Chemical abundances of magnetic and non-magnetic Herbig Ae/Be stars
Article
Article Title | Chemical abundances of magnetic and non-magnetic Herbig Ae/Be stars |
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ERA Journal ID | 1074 |
Article Category | Article |
Authors | Folsom, C. P. (Author), Bagnulo, S. (Author), Wade, G. A. (Author), Alecian, E. (Author), Landstreet, J. D. (Author), Marsden, S. C. (Author) and Waite, I. A. (Author) |
Journal Title | Monthly Notices of the Royal Astronomical Society |
Journal Citation | 422 (3), pp. 2072-2101 |
Number of Pages | 30 |
Year | 2012 |
Publisher | Oxford University Press |
Place of Publication | United Kingdom |
ISSN | 0035-8711 |
1365-2966 | |
Digital Object Identifier (DOI) | https://doi.org/10.1111/j.1365-2966.2012.20718.x |
Web Address (URL) | https://academic.oup.com/mnras/article/422/3/2072/1042307 |
Abstract | The photospheres of about 10–20 per cent of main-sequence A-and B-type stars exhibit a wide range of chemical peculiarities, often associated with the presence of a magnetic field. It is not exactly known at which stage of stellar evolution these chemical peculiarities develop. To investigate this issue, in this paper we study the photospheric compositions of a sample of Herbig Ae and Be stars, which are considered to be the pre-main-sequence progenitors of A and B stars. We have performed a detailed abundance analysis of 20 Herbig stars (three of which have confirmed magnetic fields), and one dusty young star. We have found that half the stars in our sample show λ Bootis (λ Boo) chemical peculiarities to varying degrees, only one star shows weak Ap/Bp peculiarities and all the remaining stars are chemically normal. The incidence of λ Boo chemical peculiarities we find in Herbig stars is much higher than what is seen on the main sequence. We argue that a selective accretion model for λ Boo star formation is a natural explanation for the remarkably large number of λ Boo stars in our sample. We also find that the magnetic Herbig stars do not exhibit a range of chemical compositions remarkably different from the normal stars: one magnetic star displays λ Boo chemical peculiarities (HD101412), one displays weak Ap/Bp peculiarities (V380 Ori A) and one (HD 190073) is chemically normal. This is completely different from what is seen on the main sequence, where all magnetic A and cool B stars show Ap/Bp chemical peculiarities, and this is consistent with the idea that the magnetic field precedes the formation of the chemical peculiarities typical of Ap and Bp stars. |
Keywords | stars; abundances; chemically peculiar; magnetic field; pre-main-sequence |
ANZSRC Field of Research 2020 | 370199. Atmospheric sciences not elsewhere classified |
510109. Stellar astronomy and planetary systems | |
490299. Mathematical physics not elsewhere classified | |
Public Notes | This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2012 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. |
Byline Affiliations | Armagh Observatory, United Kingdom |
Queen's University, Canada | |
Laboratory of Space Science and Astrophysical Instrumentation, France | |
University of Western Ontario, Canada | |
Anglo-Australian Observatory, Australia | |
Centre for Astronomy, Solar Radiation and Climate | |
Institution of Origin | University of Southern Queensland |
https://research.usq.edu.au/item/q15yz/chemical-abundances-of-magnetic-and-non-magnetic-herbig-ae-be-stars
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