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Title: A search for pulsations in the HgMn star HD 45975 with CoRoT photometry and ground-based spectroscopy
Authors: Morel, Thomas ×
Briquet, M
Auvergne, M
Alecian, G
Ghazaryan, S
Niemczura, E
Fossati, L
Lehmann, H
Hubrig, S
Ulusoy, C
Damerdji, Y
Rainer, M
Poretti, E
Borsa, F
Scardia, M
Schmid, Valentina
Van Winckel, Hans
De Smedt, Kenneth
Pápics, Péter
Gameiro, J. F
Waelkens, Christoffel
Fagas, M
Kaminski, K
Dimitrov, W
Baglin, A
Michel, E
Dumortier, L
Fremat, Y
Hensberge, H
Jorissen, A
Van Eck, S #
Issue Date: 2014
Publisher: EDP Sciences
Series Title: Astronomy & Astrophysics vol:561 pages:1-14
Article number: A35
Abstract: The existence of pulsations in HgMn stars is still being debated. To provide the first unambiguous observational detection of pulsations in this class of chemically peculiar objects, the bright star HD 45975 was monitored for nearly two months by the CoRoT satellite. Independent analyses of the light curve provide evidence of monoperiodic variations with a frequency of 0.7572 d-1 and a peak-to-peak amplitude of ~2800 ppm. Multisite, ground-based spectroscopic observations overlapping the CoRoT observations show the star to be a long-period, single-lined binary. Furthermore, with the notable exception of mercury, they reveal the same periodicity as in photometry in the line moments of chemical species exhibiting strong overabundances (e.g., Mn and Y). In contrast, lines of other elements do not show significant variations. As found in otherHgMn stars, the pattern of variability consists in an absorption bump moving redwards across the line profiles. We argue that the photometric and spectroscopic changes are more consistent with an interpretation in terms of rotational modulation of spots at the stellar surface. In this framework, the existence of pulsations producing photometric variations above the ~50 ppm level is unlikely in HD 45975. This provides strong constraints on the excitation/damping of pulsation modes in this HgMn star.
ISSN: 0004-6361
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Institute of Astronomy
Clinical Pharmacology and Pharmacotherapy
× corresponding author
# (joint) last author

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