Query : 2015A&A...580A..81B

2015A&A...580A..81B - Astronomy and Astrophysics, volume 580A, 81-81 (2015/8-1)

The remarkably unremarkable global abundance variations of the magnetic Bp star HD 133652.


Abstract (from CDS):

In recent years, significant effort has been made to understand how the magnetic field strengths and atmospheric chemical abundances of Ap/Bp stars evolve during their main sequence lifetime by identifying a large number of Ap/Bp stars with accurately known ages. As a next step, these stars should be studied individually and in detail to offer further insight into the physics of how such main sequence stars evolve. We have obtained high resolution spectra using the ESPaDOnS spectropolarimeter and FEROS spectrograph of the chemically peculiar, magnetic Bp star HD 133652. Using these data, we present a simple magnetic field model and abundance determinations of He, O, Mg, Si, Ti, Cr, Fe, Pr, and Nd.Abundance analysis was performed using zeeman.f, a spectral synthesis program that includes the effects of magnetic fields on line formation. The magnetic field structure is approximated as a simple, co-linear multipole expansion that reproduces the observed variations of the line-of-sight magnetic field with phase. The abundance distribution of each element was modelled using a uniform abundance in each of the two magnetic hemispheres.Using the new magnetic field measurements, we were able to refine the rotation period of HD 133652 to P=2.30405±0.00002d. The abundance analysis reveals that the elements modelled (except He, O and Mg) are overabundant compared to the Sun; however most elements studied do not show substantial differences in the large-scale mean abundances between the two magnetic hemispheres. The individual line profiles are very complex and clearly indicate the presence of significant small-scale abundance variations on the stellar surface. These data are adequate to perform a useful investigation of the magnetic field structure and abundance distribution over the stellar surface. HD 133652 is now one of a growing list of hotter Bp stars of known age for which this type of analysis has been performed.

Abstract Copyright:

Journal keyword(s): stars: abundances - stars: chemically peculiar - stars: magnetic field

Simbad objects: 8

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Number of rows : 8
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
1 V* V682 Mon a2* 06 28 10.7659506576 -04 53 56.511231684   7.85 7.97     ApSi 89 0
2 * 53 Cam a2* 08 01 42.4403874648 +60 19 27.806833200   6.177 6.008     A3VpSrSiCrEu 395 0
3 V* KQ Vel a2* 10 55 01.0131717072 -42 15 03.962480184 5.78 6.03 6.11     Ap(SiCr) 129 0
4 V* HZ Lup a2* 15 06 33.1978166352 -30 55 06.533677056   5.893 5.977     ApSi 105 0
5 V* HR Lup a2* 15 08 12.1238757000 -40 35 02.155417224 5.25 5.65 5.79     B8IVSi 166 1
6 NAME Upper Centaurus Lupus As* 15 24 -41.9           ~ 433 1
7 V* V933 Sco a2* 16 20 05.4927999744 -20 03 23.030685720   7.56 7.40     B9II/III 186 0
8 V* V970 Sco a2* 17 39 41.2405860216 -32 17 57.527626920   9.38 9.34     ~ 61 0

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