Περίληψη:
We present the results of multisite observations of the delta Scuti star
V1162 Ori. The observations were done in the period October 1999 - May
2000, when 18 telescopes at 15 observatories were used to collect 253
light extrema during a total of 290 hours of time-series observations.
The purpose of the observations was to investigate amplitude and period
variability previously observed in this star, and to search for
low-amplitude frequencies. We detect, apart from the main frequency and
its two first harmonics, four additional frequencies in the light
curves, all with low amplitudes (1-3 mmag). Combining the present data
set with data obtained in 1998-99 at ESO confirms the new frequencies
and reveals the probable presence of yet another pulsational frequency.
All five low-amplitude frequencies are statistically significant in the
data, but at least one of them (f(5)) suffers from uncertainty due to
aliasing. Using colour photometry we find evidence for a radial main
frequency (f(1)), while most or all low-amplitude frequencies are likely
non-radial. We show that the main frequency of V1162 Ori has variable
amplitude and period/phase, the latter is also displayed in the O-C
diagram from light extrema. The amplitude variability in our data is
cyclic with a period of 282 d and a range of nearly 20 mmag, but earlier
amplitude values quoted in the literature cannot be explained by this
cyclic variation. O-C analysis including data from the literature show
that the period of V1162 Ori displays a linear period change as well as
sudden or cyclic variations on a time scale similar to that of the
amplitude variations.
Συγγραφείς:
Arentoft, T
Sterken, C
Handler, G
Freyhammer, LM
Bruch,
A
Niarchos, P
Gazeas, K
Manimanis, V
Van Cauteren, P and
Poretti, E
Dawson, DW
Liu, ZL
Zhou, AY
Du, BT and
Shobbrock, RR
Garrido, R
Fried, R
Akan, MC
Ibanoglu, C
and Evren, S
Tas, G
Johnson, D
Blake, C
Kurtz, DW
