- ID:
- ivo://CDS.VizieR/J/A+A/578/A136
- Title:
- Period changes in SuperWASP eclipsing binaries
- Short Name:
- J/A+A/578/A136
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Orbital period changes of binary stars may be caused by the presence of a third massive body in the system. Here we have searched the archive of the Wide Angle Search for Planets (SuperWASP) project for evidence of period variations in 13927 eclipsing binary candidates. Sinusoidal period changes, strongly suggestive of third bodies, were detected in 2% of cases; however, linear period changes were observed in a further 22% of systems. We argue on distributional grounds that the majority of these apparently linear changes are likely to reflect longer-term sinusoidal period variations caused by third bodies, and thus estimate a higher-order multiplicity fraction of 24% for SuperWASP binaries, in good agreement with other recent figures for the fraction of triple systems amongst binary stars in general.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/511/2125
- Title:
- Period changes of 148 Galactic Cepheids
- Short Name:
- J/MNRAS/511/2125
- Date:
- 14 Feb 2022 13:42:07
- Publisher:
- CDS
- Description:
- Investigating period changes of classical Cepheids through the framework of O-C diagrams provides a unique insight to the evolution and nature of these variable stars. In this catalogue, we present the O-C diagrams and period change rates derived for 148 Galactic Classical Cepheids variables, along with the exact period values of these stars for a given date as determined by the O-C diagrams. The catalogue also contains photometric data adopted from Gaia EDR3 and the David Dunlap Observatory Cepheid Database, which were used for the study, and the results obtained from the statistical modelling of the individual O-C diagrams. We find that a significant fraction of the Cepheids show period fluctuations, which appear on the O-C diagrams as quasi-periodic waves, which could be modelled and described through the statistical framework. For completeness, we also included all photometric data collected from various previous publications and survey that were used for the research.
- ID:
- ivo://CDS.VizieR/J/AcA/56/253
- Title:
- Period changes of OGLE contact binaries
- Short Name:
- J/AcA/56/253
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Presented are results of determination of secular period changes for 569 contact binaries from the OGLE database with periods shorter than about one day and observations spanning 14 observing seasons. The statistically significant rates of secular changes found for 134 stars are distributed nearly symmetrically around zero with a half-width of the distribution equal to about 3.5x10^-7^d/yr. The remaining rates are confined within the error distribution with dispersion about 2.3x10^-7^d/yr. The largest rates of period change that have been found are of the order of 5x10^-6^d/yr.
- ID:
- ivo://CDS.VizieR/J/ApJ/834/207
- Title:
- Periodicity & magnitude of Kepler LCs variation
- Short Name:
- J/ApJ/834/207
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The variation of a stellar light curve owing to rotational modulation by magnetic features (starspots and faculae) on the star's surface can be used to investigate the magnetic properties of the host star. In this paper, we use the periodicity and magnitude of the light-curve variation as two proxies to study the stellar magnetic properties for a large sample of G-type main sequence Kepler targets, for which the rotation periods were recently determined. By analyzing the correlation between the two magnetic proxies, it is found that: (1) the two proxies are positively correlated for most of the stars in our sample, and the percentages of negative, zero, and positive correlations are 4.27%, 6.81%, and 88.91%, respectively; (2) negative correlation stars cannot have a large magnitude of light-curve variation; and (3) with the increase of rotation period, the relative number of positive correlation stars decreases and the negative correlation one increases. These results indicate that stars with shorter rotation period tend to have positive correlation between the two proxies, and a good portion of the positive correlation stars have a larger magnitude of light-curve variation (and hence more intense magnetic activities) than negative correlation stars.
- ID:
- ivo://CDS.VizieR/J/PASP/121/1188
- Title:
- Periodic variables in NGC 2301
- Short Name:
- J/PASP/121/1188
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a search for periodic variables within 4078 time-series light curves and an analysis of the period-color plane for stars in the field of the open cluster NGC 2301. One hundred thirty-eight periodic variables were discovered, of which five are eclipsing binary candidates with unequal minima. The remaining 133 periodic variables appear to consist mainly of late-type stars whose variation is due to rotation modulated by star spot activity. The determined periods range from less than a day to over 14 days and have nearly unreddened B-R colors in the range of 0.8 to 2.8. The Barnes (2003ApJ...586..464B) interpretation of the period-color plane of late type stars is tested with our data. Our data did not show distinct I and C sequences, likely due to nonmember field stars contaminating in the background, as we estimate the total contamination to be 43%. Using different assumptions, the gyrochronological age of the cluster is calculated to be 210+/-25Myr, which falls in the range of age values (164-250Myr) determined by previous studies. Finally, we present evidence which nullifies the earlier suggestion that two of the variable stars in NGC 2301 might be white dwarfs.
- ID:
- ivo://CDS.VizieR/J/A+A/554/A108
- Title:
- Periodic variables in NGC 3766
- Short Name:
- J/A+A/554/A108
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyze the population of periodic variable stars in the open cluster NGC3766 based on a 7-year multiband monitoring campaign conducted on the 1.2m Swiss Euler telescope at La Silla, Chili. The data reduction, light curve cleaning, and period search procedures, combined with the long observation time line, allowed us to detect variability amplitudes down to the mmag level. The variability properties were complemented with the positions in the color-magnitude and color-color diagrams to classify periodic variable stars into distinct variability types. We find a large population (36 stars) of new variable stars between the red edge of slowly pulsating B (SPB) stars and the blue edge of delta Sct stars, a region in the Hertzsprung-Russell (HR) diagram where no pulsation is predicted to occur based on standard stellar models. The bulk of their periods ranges from 0.1 to 0.7d, with amplitudes between 1 and 4mmag for the majority of them. About 20% of stars in that region of the HR diagram are found to be variable, but the number of members of this new group is expected to be higher, with amplitudes below our mmag detection limit. The properties of this new group of variable stars are summarized and arguments set forth in favor of a pulsation origin of the variability, with g-modes sustained by stellar rotation. Potential members of this new class of low-amplitude periodic (most probably pulsating) A and late-B variables in the literature are discussed. We additionally identify 16 eclipsing binary, 13 SPB, 14 delta Sct, and 12 gamma Dor candidates, as well as 72 fainter periodic variables. All are new discoveries. We encourage searching for this new class of variables in other young open clusters, especially in those hosting a rich population of Be stars.
- ID:
- ivo://CDS.VizieR/J/ApJS/241/35
- Title:
- Period-luminosity relations of RSGs in M33 & M31
- Short Name:
- J/ApJS/241/35
- Date:
- 11 Mar 2022
- Publisher:
- CDS
- Description:
- Based on previously selected preliminary samples of red supergiants (RSGs) in M33 and M31, the foreground stars and luminous asymptotic giant branch stars are further excluded, which leads to the samples of 717 RSGs in M33 and 420 RSGs in M31. With the time-series data from the Intermediate Palomar Transient Factory survey spanning nearly 2000 days, the period and amplitude of RSGs are analyzed. According to the light-curve characteristics, they are classified into four categories in which 84 and 56 objects in M33 and M31, respectively, are semi-regular variables. For these semi-regular variables, the pulsation mode is identified by comparing with the theoretical model, which yielded 19 (7) sources in the first overtone mode in M33 (M31), and the other 65 (49) RSGs in M33 (M31) in the fundamental mode. The period-luminosity (P-L) relation is analyzed for the RSGs in the fundamental mode. The P-L relation is found to be tight in the infrared, i.e., the Two Mircon All-Sky Survey (2MASS) JHK_S_ bands and the short-wavelength bands of Spitzer. Meanwhile, the inhomogeneous extinction causes the P-L relation scattering in the V band, and the dust emission causes the less tight P-L relation in the Spitzer/[8.0] and [24] bands. The derived P-L relations in the 2MASS/K_S_ band are in agreement with those of RSGs in the Small Magellanic Cloud, the Large Magellanic Cloud, and the Milky Way within the uncertainty range. It is found that the number ratio of RSGs pulsating in the fundamental mode to the first overtone mode increases with metallicity.
- ID:
- ivo://CDS.VizieR/J/A+A/556/A38
- Title:
- Period-mass-loss rate relation of Miras
- Short Name:
- J/A+A/556/A38
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery that Mira variables with and without absorption lines of the element technetium (Tc) occupy two different regions in a diagram of near- to mid-IR colour versus pulsation period. Tc is an indicator of a recent or ongoing mixing event called the third dredge-up (3DUP), and the near- to mid-IR colour, such as the (K-[22]) colour where [22] is the the 22um band of the WISE space observatory, is an indicator of the dust mass-loss rate of a star. We collected data from the literature about the Tc content, pulsation period, and near- and mid-IR magnitudes of more than 190 variable stars on the asymptotic giant branch (AGB) to which Miras belong. The sample is naturally biased towards optical AGB stars, which have low to intermediate (dust) mass-loss rates.
- ID:
- ivo://CDS.VizieR/J/AJ/135/1459
- Title:
- Period of M15 variable stars
- Short Name:
- J/AJ/135/1459
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new BVI CCD photometry for variables in the globular cluster M15. Our photometry was obtained using both the image subtraction package ISIS and DAOPHOT/ALLFRAME. The data were acquired in 2001 on two observing runs on 11 observing nights using the 2m telescope of the Bulgarian National Astronomical Observatory "Rozhen" with a Photometrics CCD camera. For 39 previously known variables, we present a period for the first time, and improved periods were obtained for many previously known variables. Fourteen new variables are reported. We present updated Bailey diagrams for the cluster, and discuss its Oosterhoff classification. Although many of M15's RRab pulsators fall at an intermediate locus between Oosterhoff types I and II (OoII) in the Bailey diagram, we argue that M15 is indeed a bona fide OoII globular cluster.
- ID:
- ivo://CDS.VizieR/J/A+A/489/321
- Title:
- Period study of TW Draconis
- Short Name:
- J/A+A/489/321
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a study of time series data for the Algol-type eclipsing binaries TW Draconis obtained over the past 150 years to detect changes in minima timings. There is significant evidence for miscellaneous interacting physical processes in the system, which manifest themselves as for example period and light curve changes. Using 561 available minima timings, we compile an extended O-C diagram analysis. A detailed description of period changes allows us to construct the true phased light curve at any moment. The timing residuals (according to the linear ephemeris) display two stages of differing behaviour in 1858-2007. The first part ends around 1942. It is characterized by more or less smooth linear/parabolic course of timing residuals. In 1858-1905, the period was almost constant P=2.806513(9)d, but, in 1905-1942, the period increased due to mass exchange between components. Since 1942, the system has been showing alternating and shortening period changes with the length of a cycle of about two decades, modulated by short-term periodic variations. The latter small variations with the period 6.5-years are caused by the light-time effect due to the presence of a third low-mass body in the system. Major oscillations can be explained as consequences of quadrupole moment variation in the system.
