Line-profile variability from tidal flows in Alpha Virginis (Spica)


D.M. Harrington$^1$, G. Koenigsberger$^2$, E. Moreno$^3$, J.R. Kuhn$^1$

1 - Institute for Astronomy, U Hawaii, 2 - Instituto de Ciencias Fisicas,Universidad Nacional Aut'onoma de M'exico, 3 - Instituto de Astronom'{i}a, Universidad Nacional Aut'onoma de M'exico

We present the results of high precision, high resolution (R$sim$68000) optical observations of the short-period (4d) eccentric binary system Alpha Virginis (Spica) showing the photospheric line-profile variability that in this system can be attributed to non-radial pulsations driven by tidal effects. Although scant in orbital phase coverage, the data provide S/N$>$2000 line profiles at full spectral resolution in the wavelength range $Deltalambda$4000--8500{AA}, allowing a detailed study of the night-to-night variability as well as changes that occur on $sim$2 hr timescale. Using an {it ab initio} theoretical calculation, we show that the line-profile variability can arise as a natural consequence of surface flows that are induced by the tidal interaction.

Reference: ApJ, In Press
Status: Manuscript has been accepted

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Email: dmh@ifa.hawaii.edu