Short time light variations of Ap-stars

Hildebrandt, G.; Schöneich, W.; Lange, D.; Želwanowa, E.; Hempelmann, A.

doi:10.1007/978-94-009-4714-6_30

Cited by 2 publications

(4 citation statements)

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“…In recent years, the most often quoted example of a short-period, hot pulsator has been the B9p(Si) star ET And. This star was suspected by Hildebrandt, Schoneich & Lange (1985) and Kuschnig et al (1990) to show <5 Scuti-like variability of 0.10 d and a peak-to-peak amplitude of about 4 mmag in B. This variability would be superposed on the 1.6 d variations caused by the rotation of this peculiar Si star.…”

Section: Et and And The Maia Variablesmentioning

confidence: 73%

Astrophysical Applications of Delta Scuti Stars

Breger

1995

International Astronomical Union Colloquium

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The δ Scuti stars pulsate with a large number of low-order radial and nonradial p-modes. There also exists some evidence for the presence of g-modes.The pulsational variability outside the classical δ Scuti star instability strip (A1V - F0V on the main sequence) is examined. New measurements do not confirm the short-period variability of the hot B9p star ET And. However, a number of cool, early-F stars shows variability around one day: the γ Dor variables. An explanation involving nonradial g modes appears the most promising.An examination of available information on the multi-periodicity of δ Scuti stars shows no systematic behaviour in which pulsation modes axe excited to an observable level with luminosity and temperature. The asteroseismological potential of δ Scuti vaxiables is briefly examined.So far, the period changes of five luminous Pop. I δ Scuti variables have been studied. While stellar evolution predicts period increases, decreases have been observed and reported for all five stars. The statistical significance of this result and alternative explanations axe briefly examined.

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Section: Et and And The Maia Variablesmentioning

confidence: 73%

Astrophysical Applications of Delta Scuti Stars

Breger

1995

International Astronomical Union Colloquium

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“…On top of it, Gerth (1986) reported radial velocity variations of this star with a period of 0.2 day. The dependence of the amplitude of the light variations on the orbital phase of the binary system suggested by Hildebrandt (1981) could not be confirmed later (Hildebrandt et al, 1985). The nature of ET And, a star lying between the regions of the & Set and P Cep pulsating variables, is obscure.…”

Section: The Nonrotational Variability Of the Cp Starsmentioning

confidence: 91%

“…The star shows light variations on two different time scales: one with the rotation period P = 1.6 days, and the other with a time scale of about 0.1 day and an amplitude of about 0.01 mag. The observed light variability due to the shorter time scale cannot be explained with only one period (Panov, 1978;Hildebrandt et al, 1985). On top of it, Gerth (1986) reported radial velocity variations of this star with a period of 0.2 day.…”

Section: The Nonrotational Variability Of the Cp Starsmentioning

confidence: 96%