A&A Supplement series, Vol. 122, April I 1997, 131-147
Received January 2; accepted July 19, 1996
Scuti stars
E. Solano
- J. Fernley
Send offprint request: E. Solano; esm@vilspa.esa.es
INSA, ESA-IUE Observatory, P.O. Box 50727, 28080 Madrid, Spain
IUE Observatory, P.O. Box 50727, 28080 Madrid, Spain
Projected rotational velocities and effective temperatures for
Sct stars as well as 41 non-variable stars of similar spectral
type and luminosity are presented here. The rotational velocities have been calculated following
the method developed in Gray (1992) and effective temperatures
have been derived using the Balmer line profiles. The temperatures
obtained from this method are shown to be in reasonable agreement with those calculated
using the Infrared Flux Method (IRFM) or spectrophotometric methods. This result
has allowed us to use our temperatures to compare different
photometric
calibrations. We find that the calibration given by Moon & Dworetsky
(1985) is the most consistent. In the second part of this paper we have
studied the relation between the pulsational properties (periods and
amplitudes) and the physical parameters (
and 
).
Where pulsation modes have been determined, the low amplitude 
Scutis tend to be multimode (radial and non-radial) pulsators,
consistent with the theory that non-linear coupling between modes acts to
limit the amplitude in these stars. We have compared the
distribution of 
for low amplitude 
Scutis and
non-variable stars. This shows the 
Scutis have a broader
distribution in 
suggesting that a high rotation velocity may
favour pulsation. We find
that the large amplitude 
Scuti stars tend to have longer periods,
cooler temperatures and lower rotation velocities. Given that the large
amplitude stars are also relatively rare all the above are consistent with
the hypothesis that these stars are more evolved (sub-giants) than the low
amplitude 
Scutis (main sequence or early post-main sequence).
keywords: stars: rotation --
stars: fundamental parameters --
stars: variables: 
Sct