A frequency analysis of the p-mode pulsations of the Ap SrEu(Cr) star HD 119027 |
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Authors: | Peter Martinez C Koen & D J Sullivan |
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Institution: | South African Astronomical Observatory, PO Box 9, Observatory 7935, South Africa,;Physics Department, Victoria University, PO Box 600, Wellington, New Zealand |
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Abstract: | We present new high-speed, multisite photometric observations of the rapidly oscillating Ap star HD 119027 acquired over seven nights during 1996. A frequency analysis of these observations reveals the presence of oscillations at 1835, 1875, 1888, 1913, 1940, 1942 and (possibly) 1953 μHz. These frequencies are consistent with a spacing of either 13 or 26 μHz, depending on the reality of the oscillations at 1875 and 1953 μHz. The data in hand do not permit us to discriminate between the two possible spacings. If the smaller value of the spacing is correct, it suggests that HD 119027 is outside the main-sequence band. Two of the frequencies listed above are separated by only 1.95 μHz, suggesting that they are modes of ( n ,ℓ) and ( n − 1, ℓ + 2), which in roAp stars is a quantity governed by the internal magnetic field. |
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Keywords: | stars: chemically peculiar stars: individual: HD 119027 stars: oscillations stars: variables: other |
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