A spectroscopic study of the Scuti star rho Puppis
P. Mathias
- D. Gillet
- C. Aerts
- M.G. Breitfellner
Received 18 March 1997; accepted 21 July 1997
Abstract:
We present a spectroscopic analysis of the delta Scuti star rho Pup
on the basis of high resolution data spread over 4 consecutive nights.
Despite the
clearly sinusoidal shape of the radial-velocity curves, cycle-to-cycle
variations are observed. A frequency analysis points towards the already known
frequency nu0=7.098168 c/d assigned to a radial mode and towards
two possible secondary non-radial
oscillations at nu1=7.8 c/d and nu2=6.3 c/d
of much smaller amplitude.
Using the moment method we confirm that the main
oscillation is a radial mode. The second mode is found to be axisymmetric,
but because of its small
amplitude and our relatively small data set, no more detailed information on
its pulsation parameters could be derived. The third frequency, if real,
corresponds to a non-axisymmetric mode.
The running wave effect may be present between the FeI and Halpha
lines, the latter being late by about 0.5% of the pulsation period.
No evidence is found in our observed profiles (CaI, FeI, Halpha)
for a shock wave mechanism as previously suggested by Dravins et al. (1977).
New observations are required to confirm the
presence of a period-dependent shock wave which should be of weak intensity.
Keywords:
Stars: oscillations -- Stars: variables: delta Scuti -- Stars:
individual: rho Pup
Back
Home