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Astron. Astrophys. 341, 853-856 (1999)

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On the occurrence of a shock wave in the atmosphere of [FORMULA] Puppis *

P. Mathias 1, D. Gillet 2 and A. Lèbre 3

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

Received 5 August 1998 / Accepted 27 October 1998


New high temporal and spectral resolution observations of the Ca II K absorption profile of the [FORMULA] Scuti star [FORMULA] Puppis are presented. The data cover 1.2 pulsation cycle. Contrary to the result of Dravins et al. (1977), the line profile corresponding to the phase just before the maximum acceleration (monitored twice here), does not show any emission feature. Thus, the Ca II K emission may be of transient nature. Consequently, the intensity of the shock wave should be weak and strongly variable. This result is consistent with a previous study (Mathias et al. 1997) where no shock wave signature was present in the H[FORMULA] and metallic line profiles observed. Thus, additional observations are required to specify the frequency of occurrence of the transient emission.

Key words: line: profiles – shock waves – stars: individual: ae Pup – stars: oscillations – stars: variables: ffi Sct

* Based on observations obtained at the European Southern Observatory (La Silla, Chile)

© European Southern Observatory (ESO) 1999

Online publication: December 16, 1998