scholarly journals A triplet of the only pulsation mode detected in the DAV star G132–12

2021 ◽  
Vol 21 (6) ◽  
pp. 139
Author(s):  
Wen-Chao Su ◽  
Jian-Ning Fu ◽  
Jian-Xing Chen ◽  
Lester Fox-Machado ◽  
Shi-Jie Zhao ◽  
...  
Keyword(s):  
Pulsation Mode

scholarly journals Prospects of Variable Star Research by Future Space Missions

2000 ◽  
Vol 176 ◽  
pp. 41-45
Author(s):  
Laurent Eyer
Keyword(s):  
Time Series ◽  
Variable Star ◽  
Space Missions ◽  
Planet Detection ◽  
Pulsation Mode ◽  
National Space ◽  
Future Space ◽  
The Future

AbstractESA and NASA are studying projects having a tremendous return on variable star research. Other national space agencies are also studying or developing projects of smaller costs but with impressive returns. The projects range from global Galactic surveys like the ESA mission GAIA which will give photometric time series for about 1 billion stars, to detailed pulsation-mode studies like the CNES mission COROT which could reach a photometric precision lower than 1 ppm. The presentation will emphasize the future astrometric, asteroseismological and planet detection missions.

scholarly journals Pulsation Modes in Mira and Semiregular Variables

1999 ◽  
Vol 191 ◽  
pp. 108-116
Author(s):  
Michael Feast
Keyword(s):  
Globular Clusters ◽  
Direct Evidence ◽  
Light Curves ◽  
Mode Switching ◽  
Pulsation Mode ◽  
Conventional Models ◽  
Angular Diameters

The most direct evidence for the pulsation mode of Mira and SR variables comes from the linear diameters derived from individual parallaxes and angular diameters, together with the observed periods. The data now available strongly suggest that most, if not all, Miras and SRs pulsate in the same mode. If comparison is made with conventional models, this mode is the first overtone. Uncertainties in deriving the pulsational radius of a Mira from the observations do not appear significant enough to affect this conclusion. Evidence from SRs and Miras in globular clusters supports this conclusion and shows that the pulsation mode does not depend on metallicity. Analysis of light curves leads to broadly the same conclusions, if less directly. The light curves indicate that periodicities other than the main one may also be present and that mode switching may occur in some stars.

scholarly journals Close Frequency Pairs in Delta Scuti Stars

2002 ◽  
Vol 185 ◽  
pp. 326-327
Author(s):  
K.M. Bischof ◽  
M. Breger
Keyword(s):  
Phase Shift ◽  
Power Spectra ◽  
Phase Changes ◽  
Single Frequency ◽  
Sufficient Data ◽  
Amplitude Variability ◽  
Pulsation Mode ◽  
Delta Scuti ◽  
Close Frequency ◽  
Scuti Stars

AbstractThe power spectra of several δ Scuti stars show close peaks with similar frequencies and amplitudes. Apart from possible observational problems, this can be interpreted in terms of two separate pulsation modes with similar, close frequencies or an artifact of amplitude variability of a single pulsation mode. If sufficient data are available, it is possible to distinguish between the two hypotheses on the basis of expected systematic phase changes associated with the amplitude variations of an assumed single frequency. This phase-shift test has been applied to modes found for BI CMi. In this paper we present the evidence for one of the close frequency pairs found in this star.

scholarly journals An additional pulsating mode (7.35 mHz) and pulsations timing variations of PG 1613+426

2017 ◽  
Vol 26 (1) ◽  
Author(s):  
Tomomi Otani ◽  
Terry D. Oswalt ◽  
Patrice Majewski ◽  
Riley Jordan ◽  
Marc Amaral ◽  
...  
Keyword(s):  
Confidence Level ◽  
Instability Strip ◽  
Photometric Analysis ◽  
Companion Star ◽  
Pulsation Mode ◽  
Sdb Stars ◽  
Low Mass

AbstractWe present the detection of an additional pulsation mode (7.35 mHz) of a subdwarf B star, PG 1613+426, and periodic Observed minus Calculated (O-C) variations for two existing pulsations. PG 1613+426 is near the hot end of the sdB instability strip. One pulsation mode (6.94 mHz) was detected so far by Bonanno et al. (2002) and another pulsation mode candidate (7.05 mHz) was proposed with a confidence level above 90% by Kuassivi and Ferlet (2005). To constrain sdB star evolutional scenarios, this star was monitored in 2010, 2011, 2015, and 2017 as a part of a project for finding companions to sdB stars using the pulsation timing method. The photometric analysis of those data shows an additional 7.35 mHz pulsation mode as well as the previously detected 6.93 mHz mode. However the 7.05 mHz mode was not detected. Nightly amplitude changes of 7.35 mHz mode were observed in the 2011 data, however the 2017 data did not show nightly amplitude shifts. O-C variations were detected in both 6.93 mHz and 7.35 mHz pulsations, indicating that PG 1613+426 may have a low mass companion star. However, more observations are needed to confirm it.

Effect of Alternating Electric Current on Pulsation Mode of Rat Major Arteries In Situ

2019 ◽  
Vol 167 (3) ◽  
pp. 305-310
Author(s):  
S. V. Revenko ◽  
L. N. Tikhomirova ◽  
I. Yu. Gavrilov ◽  
I. A. Tarakanov
Keyword(s):  
Electric Current ◽  
Pulsation Mode ◽  
Alternating Electric Current

Mapping the Non-Radial Pulsations

2000 ◽  
Vol 175 ◽  
pp. 268-271
Author(s):  
S.V. Berdyugina ◽  
H. Korhonen ◽  
C. Schrijvers ◽  
J.H. Telting
Keyword(s):  
High Resolution ◽  
Imaging Technique ◽  
Temperature Fluctuations ◽  
Dominant Mode ◽  
Type Star ◽  
Surface Imaging ◽  
Pulsation Mode ◽  
Radial Pulsations

AbstractWe apply the surface imaging technique to high-resolution spectra of the rapidly rotating β Cep-type star ω1 Sco. Assuming only temperature fluctuations due to pulsations, we obtain a map of the surface corotating with the dominant pulsation mode. Prom the map we identify the dominant mode and find traces of a second pulsation mode. We conclude that the traditional surface imaging technique can be successfully used for mapping stellar non-radial pulsations.

scholarly journals Bisector Velocities of Hα in the roAp Star α Cir: Probing the Principal Pulsation Mode

1998 ◽  
Vol 185 ◽  
pp. 309-310
Author(s):  
I. K. Baldry ◽  
T. R. Bedding ◽  
M. Viskum ◽  
H. Kjeldsen ◽  
S. Frandsen
Keyword(s):  
Dipole Mode ◽  
Principal Mode ◽  
Pulsation Mode ◽  
Roap Star

α Circini is the brightest of the known rapidly oscillating Ap (roAp) stars. Previous observations of this star in photometry (Kurtz et al. 1994) have shown that it has one dominant pulsation mode, which is a pure oblique dipole mode (ℓ = 1) with a frequency of 2442 μHz (P = 6.825 min). Kurtz et al. (1994) measured the amplitude of the principal mode to be 2.55 mmag (Strömgren v).

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