000004083 001__ 4083
000004083 005__ 20190202205100.0
000004083 037__ $$aSCART-2019-0126
000004083 100__ $$aGonzález, J.F.
000004083 245__ $$aHD96446: a long-period binary with a strongly magnetic He-rich primary with beta Cep pulsations
000004083 260__ $$c2019
000004083 520__ $$aAims: HD 96446 is a magnetic B2p He-strong star that has been reported to be a β Cep pulsator. We present a detailed spectroscopic analysis of this object based on an intensive observational data set obtained in a multisite campaign with the spectrographs Coralie, Feros, and Harps (La Silla), Uves (Paranal), Hercules (Mt. John Observatory), and Giraffe (SAAO). Methods: Radial velocities were measured by cross-correlations and analyzed to detect periodic variations. On the other hand, the mean spectrum was fitted with spectral synthesis to derive atmospheric parameters and chemical abundances. Results: From the analysis of radial velocities HD 96446 was discovered to be a spectroscopic binary with a period of 799 days. The stellar companion, that contributes only ∼5% of the total flux, is an A0-type star. A frequency analysis of the radial velocities allows to detect two pulsational modes with periods 2.23 h and 2.66 h. The main mode is most probably a low-inclination, dipole mode (l, m) = (1,0) and the second pulsation mode corresponds to (l, m) = (2,2) or to a pole-on (l, m) = (3,2) configuration. Besides radial velocities, the main pulsation mode is evidenced through small variations of the spectral morphology (temperature variations) and the light flux. The rotation period, of 23.4 d, was detected through the variation of line intensities. Chemical abundances are unevenly distributed over the stellar surface, with helium concentrated on the negative magnetic pole and most metals strengthened at lower latitudes. The mean chemical abundance of helium is strongly abnormal reaching 0.60 by number.
000004083 594__ $$aNO
000004083 6531_ $$abinaries: spectroscopic
000004083 6531_ $$astars: chemically peculiar
000004083 6531_ $$astars: early-type
000004083 6531_ $$astars: magnetic field
000004083 6531_ $$astars: oscillations (including pulsations)
000004083 6531_ $$astars: individual: HD 96446
000004083 700__ $$aBriquet, M.
000004083 700__ $$aPrzybilla, N.
000004083 700__ $$aNieva, M.-F.
000004083 700__ $$aDe Cat, P.
000004083 700__ $$aSaesen, S.
000004083 700__ $$aHubrig, S.
000004083 700__ $$aThoul, A.
000004083 700__ $$aPápics, P.I.
000004083 700__ $$aPalaversa, L.
000004083 700__ $$aNaef, D.
000004083 700__ $$aNeveu-Van Malle, M.
000004083 700__ $$aJärvinen, S.
000004083 700__ $$aPollard, K.R.
000004083 700__ $$aKilmartin, P.
000004083 700__ $$aMowlavi, N.
000004083 700__ $$aButler, K.
000004083 773__ $$pAstronomy & Astrophysics$$y2019
000004083 8560_ $$fpeter.decat@observatoire.be
000004083 905__ $$asubmitted to
000004083 980__ $$aREFERD