uu.seUppsala University Publications
Change search
ReferencesLink to record
Permanent link

Direct link
Magnetic field topology of the unique chemically peculiar star CU Virginis
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Observational Astronomy.
2014 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 565, A83- p.Article in journal (Refereed) Published
Abstract [en]

Context. The late-B, magnetic, chemically peculiar star CU Vir is one of the fastest rotators among the intermediate-mass stars with strong fossil magnetic fields. It shows a prominent rotational modulation of the spectral energy distribution and absorption line profiles due to chemical spots and exhibits a unique, strongly beamed variable radio emission. Aims. Little is known about the magnetic field topology of CU Vir. In this study, we aim to derive detailed maps of the magnetic field distribution over the surface of this star for the first time. Methods. We use high-resolution spectropolarimetric observations covering the entire rotational period. These data are interpreted using a multi-line technique of least-squares deconvolution (LSD) and a new Zeeman Doppler imaging code, which is based on detailed polarised radiative transfer modelling of the Stokes I and V LSD profiles. This new magnetic inversion approach relies on the spectrum synthesis calculations over the full wavelength range that is covered by observations and does not assume that the LSD profiles behave as a single spectral line with mean parameters. Results. We present magnetic and chemical abundance maps derived from the Si and Fe lines. Mean polarisation profiles of both elements reveal a significant departure of CU Vir's magnetic field topology from the commonly assumed axisymmetric dipolar configuration. The field of CU Vir is dipolar-like but clearly non-axisymmetric, showing a large difference in the field strength between the regions of opposite polarity. The main relative abundance depletion features in both Si and Fe maps coincide with the weak-field region in the magnetic map. Conclusions. The detailed information on the distorted dipolar magnetic field topology of CU Vir provided by our study is essential for understanding chemical spot formation, radio emission, and rotational period variation of this star.

Place, publisher, year, edition, pages
2014. Vol. 565, A83- p.
Keyword [en]
stars: atmospheres, stars: chemically peculiar, stars: magnetic field, starspots, stars: individual: CU Virginis
National Category
Astronomy, Astrophysics and Cosmology
URN: urn:nbn:se:uu:diva-228485DOI: 10.1051/0004-6361/201423472ISI: 000336730900083OAI: oai:DiVA.org:uu-228485DiVA: diva2:734219
Available from: 2014-07-15 Created: 2014-07-15 Last updated: 2014-07-15Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Kochukhov, Oleg
By organisation
Observational Astronomy
In the same journal
Astronomy and Astrophysics
Astronomy, Astrophysics and Cosmology

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 533 hits
ReferencesLink to record
Permanent link

Direct link