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On the occurrence of the shock wave in the atmosphere of $\rho$Puppis

P. Mathias¹ - D. Gillet² - A. Lèbre³

¹ Observatoire de la Côte d'Azur, Département Fresnel, UMR 6528,
BP 4229, F-06304 Nice Cedex 04, France, email: mathias@obs-nice.fr
² Observatoire de Haute-Provence,
F-04870 St Michel l'Observatoire, France, email: gillet@obs-hp.fr
³ GRAAL cc072, Université Montpellier II,
F-34095 Montpellier Cedex 05, France, email: lebre@graal.univ-montp2.fr

Received ...; accepted ...

Abstract:

New high temporal and spectral resolution observations of the CaiiK absorption profile of the $\delta$Scuti star $\rho$Puppis are presented. They covered 1.2 pulsation cycle during which the phase just before the maximum acceleration is observed twice. No emission feature is detected contrary to the previous observation of Dravins et al. (1977). Thus, it seems that the nature of the CaiiK emission is transient and the intensity of the shock wave which is weak and strongly variable at its origin. This is consistent with our previous study (Mathias et al. 1997) in which we have not seen any shock wave signature on some metallic lines and the H$\alpha$ one. Additional observations are required to precise the frequency occurrence of the emission.

Stars: oscillations - Stars: variables: $\delta$Scuti - Stars: individual: $\rho$Pup