2011A&A...534L..13K


Query : 2011A&A...534L..13K

2011A&A...534L..13K - Astronomy and Astrophysics, volume 534, L13-13 (2011/10-1)

No magnetic field in the spotted HgMn star µ Leporis.

KOCHUKHOV O., MAKAGANIUK V., PISKUNOV N., JEFFERS S.V., JOHNS-KRULL C.M., KELLER C.U., RODENHUIS M., SNIK F., STEMPELS H.C. and VALENTI J.A.

Abstract (from CDS):

Chemically peculiar stars of the mercury-manganese (HgMn) type represent a new class of spotted late-B stars, in which evolving surface chemical inhomogeneities are apparently unrelated to the presence of strong magnetic fields but are produced by some hitherto unknown astrophysical mechanism. The goal of this study is to perform a detailed line profile variability analysis and carry out a sensitive magnetic field search for one of the brightest HgMn stars - µ Lep. We acquired a set of very high-quality intensity and polarization spectra of µ Lep with the HARPSpol polarimeter. These data were analyzed with the multiline technique of least-squares deconvolution in order to extract information on the magnetic field and line profile variability. Our spectra show very weak but definite variability in the lines of Sc, all Fe-peak elements represented in the spectrum of µ Lep, as well as Y, Sr, and Hg. Variability might also be present in the lines of Si and Mg. Anomalous profile shapes of TiII and YII lines suggest a dominant axisymmetric distribution of these elements. At the same time, we found no evidence of the magnetic field in µ Lep, with the 3σ upper limit of only 3G for the mean longitudinal magnetic field. This is the most stringent upper limit on the possible magnetic field derived for a spotted HgMn star. The very weak variability detected for many elements in the spectrum µ Lep suggests that low-contrast chemical inhomogeneities may be common in HgMn stars and that they have not been recognized until now due to the limited precision of previous spectroscopic observations and a lack of time-series data. The null result of the magnetic field search reinforces the conclusion that formation of chemical spots in HgMn stars is not magnetically driven.

Abstract Copyright:

Journal keyword(s): stars: chemically peculiar - stars: individual: HD33904 - stars: magnetic field - starspots - polarization

Simbad objects: 3

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Number of rows : 3
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 * phi Phe SB* 01 54 22.0319152104 -42 29 48.942141036   5.055 5.109     A3V 109 0
2 * 66 Eri a2* 05 06 45.6527881872 -04 39 18.601025148 4.89 5.06 5.12     B9V 147 1
3 * mu. Lep a2* 05 12 55.9029641016 -16 12 19.668599100 2.78 3.18 3.29 3.30 3.42 B9IV:HgMn 270 1

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2022.10.07-05:03:43

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