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- ID:
- ivo://CDS.VizieR/J/A+A/445/423
- Title:
- WeCAPP Survey. M31 variables
- Short Name:
- J/A+A/445/423
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The observations in the WeCAPP microlensing survey towards the Andromeda galaxy (M31) for a period of three years (2000-2003) resulted in a database with unprecedented time coverage for an extragalactic variable star study. We have monitored a 16.1' x 16.6' field centered on the nucleus of M31 in two optical bands (R and I) using the 0.8-m telescope at Wendelstein, Germany and the 1.2-m telescope at Calar Alto, Spain. Using the difference imaging method we detected 23781 variable sources for which we calculated the periods and variation amplitudes. We classified the variables according to their position in the R-band period-amplitude plane. Three groups can be distinguished; while the first two groups can be mainly associated with Cepheid-like variables (population I Cepheids in group I; type II Cepheids and RV Tauri stars in group II), the third one consists of Long Period Variables (LPVs). We detected 37 RV Tauri stars and 11 RV Tauri candidates, which makes this catalogue one of the largest collections of this class of stars to date. The classification scheme is supported by Fourier decomposition of the light curves. The catalogue of variable stars contains the positions, the periods in R and I, the significance of the assigned periods, and the variation amplitudes in the R and I bands.
- ID:
- ivo://CDS.VizieR/J/A+A/573/A100
- Title:
- WFCAM Variable Star Catalog
- Short Name:
- J/A+A/573/A100
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Stellar variability in the near-infrared (NIR) remains largely unexplored. The exploitation of public science archives with data-mining methods offers a perspective for a time-domain exploration of the NIR sky. We perform a comprehensive search for stellar variability using the optical-NIR multiband photometric data in the public Calibration Database of the WFCAM Science Archive (WSA), with the aim of contributing to the general census of variable stars and of extending the current scarce inventory of accurate NIR light curves for a number of variable star classes.
- ID:
- ivo://CDS.VizieR/J/ApJS/237/28
- Title:
- WISE catalog of periodic variable stars
- Short Name:
- J/ApJS/237/28
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have compiled the first all-sky mid-infrared variable-star catalog based on Wide-field Infrared Survey Explorer five-year survey data. Requiring more than 100 detections for a given object, 50282 carefully and robustly selected periodic variables are discovered, of which 34769 (69%) are new. Most are located in the Galactic plane and near the equatorial poles. A method to classify variables based on their mid-infrared light curves is established using known variable types in the General Catalog of Variable Stars. Careful classification of the new variables results in a tally of 21427 new EW-type eclipsing binaries, 5654 EA-type eclipsing binaries, 1312 Cepheids, and 1231 RR Lyrae. By comparison with known variables available in the literature, we estimate that the misclassification rate is 5% and 10% for short- and long- period variables, respectively. A detailed comparison of the types, periods, and amplitudes with variables in the Catalina catalog shows that the independently obtained classifications parameters are in excellent agreement. This enlarged sample of variable stars will not only be helpful to study Galactic structure and extinction properties, but can also be used to constrain stellar evolution theory and provide potential candidates for the James Webb Space Telescope.
- ID:
- ivo://CDS.VizieR/J/MNRAS/453/133
- Title:
- WISE view of RV Tauri stars
- Short Name:
- J/MNRAS/453/133
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a detailed study based on infrared (IR) photometry of all Galactic RV Tauri stars from the General Catalogue of Variable Stars (GCVS). RV Tauri stars are the brightest among the Population II Cepheids. They are thought to evolve away from the asymptotic giant branch (AGB) towards the white dwarf domain. IRAS detected several RV Tauri stars because of their large IR excesses and it was found that they occupy a specific region in the [12]-[25], [25]-[60] IRAS two-colour diagram. We used the all sky survey of Wide-field Infrared Survey Explorer to extend these studies and compare the IR properties of all RV Tauri stars in the GCVS with a selected sample of post-AGB objects with the goal to place the RV Tauri pulsators in the context of post-AGB evolution. Moreover, we correlated the IR properties of both the RV Tauri stars and the comparison sample with other observables like binarity and the presence of a photospheric chemical anomaly called depletion. We find that Galactic RV Tauri stars display a range of IR properties and we differentiate between disc sources, objects with no IR excess and objects for which the spectral energy distribution (SED) is uncertain. We obtain a clear correlation between disc sources and binarity. RV Tauri stars with a variable mean magnitude are exclusively found among the disc sources. We also find evidence for disc evolution among the binaries. Furthermore our studies show that the presence of a disc seems to be a necessary but not sufficient condition for the depletion process to become efficient.
1046. Wra 751 light curves
- ID:
- ivo://CDS.VizieR/J/A+A/484/463
- Title:
- Wra 751 light curves
- Short Name:
- J/A+A/484/463
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Wra 751 is a Luminous Blue Variable that lately exhibits strong changes in light and colour. We summarize the available photometry of Wra 751, present new photometric observations, and discuss these data with special attention on the systematic differences between the various data sources. In addition, we establish an empirical relationship between b-y and B-V for this class of stars. Wra 751 is a strong-active member of the S Dor class exhibiting very-long term S Doradus phases with an amplitude of about two magnitudes in V and a cycle length of several decades. The associated B-V colour-index amplitude is about 0.4mag. At this moment this LBV, which is the reddest member of the class, goes through the bright (and red) stage of a long-term S Dor cycle. The S Dor behaviour of this system shows some resemblance to the temporal characteristics of the Galactic LBV AG Car: time scales and amplitudes of light and colour variability are very similar.
- ID:
- ivo://CDS.VizieR/J/A+AS/120/429
- Title:
- WW Vul B light curve during 1898-1966
- Short Name:
- J/A+AS/120/429
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photographic magnitudes are presented for the irregular variable WW Vulpeculae. They were derived from Argelander brightness estimates carried out on N=2774 plates of the Harvard College Observatory Plate Collection. The data set covers the period 1898 to 1966.
- ID:
- ivo://CDS.VizieR/J/AJ/162/92
- Title:
- 126 X-rays sources around the cepheid {eta} Aql
- Short Name:
- J/AJ/162/92
- Date:
- 14 Mar 2022 07:02:20
- Publisher:
- CDS
- Description:
- X-ray bursts have recently been discovered in the Cepheids {delta}Cep and {beta}Dor modulated by the pulsation cycle. We have obtained an observation of the Cepheid {eta}Aql with the XMM-Newton satellite at the phase of maximum radius; the phase at which there is a burst of X-rays in {delta}Cep. No X-rays were seen from the Cepheid {eta}Aql at this phase, and the implications for Cepheid upper atmospheres are discussed. We have also used the combination of X-ray sources, as well as Gaia and 2MASS data, to search for a possible grouping around the young intermediate mass Cepheid. No indication of such a group was found.
- ID:
- ivo://CDS.VizieR/J/ApJ/788/105
- Title:
- XSTPS RR Lyrae in the north Galactic cap
- Short Name:
- J/ApJ/788/105
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of RR Lyrae stars (RRLs) observed by the Xuyi Schmidt Telescope Photometric Survey (XSTPS). The area we consider is located in the north Galactic cap, covering ~376.75 deg^2^ at RA~150{deg} and DE~27{deg} down to a magnitude limit of i~19. Using the variability information afforded by the multi-epoch nature of our XSTPS data, combined with colors from the Sloan Digital Sky Survey, we are able to identify candidate RRLs. We find 318 candidates, derive distances to them, and estimate the detection efficiency. The majority of our candidates have more than 12 observations, and for these we are able to calculate periods. These also allow us to estimate our contamination level, which we predict is between 30% and 40%. Finally, we use the sample to probe the halo density profile in the 9-49 kpc range and find that it can be well fitted by a double power law. We find good agreement between this model and the models derived for the south Galactic cap using the Watkins et al. (2009, J/MNRAS/398/1757) and Sesar et al. (2010, J/ApJ/708/717) RRL data sets, after accounting for possible contamination in our data set from Sagittarius stream members. We consider non-spherical double power-law models of the halo density profile and again find agreement with literature data sets, although we have limited power to constrain the flattening due to our small survey area. Much tighter constraints will be placed by current and future wide-area surveys, most notably ESA's astrometric Gaia mission. Our analysis demonstrates that surveys with a limited number of epochs can effectively be mined for RRLs. Our complete sample is provided as accompanying online material; as an example the first few entries of each electronic table are shown in the text.
- ID:
- ivo://CDS.VizieR/J/MNRAS/427/1517
- Title:
- XY And and UZ Vir light curves
- Short Name:
- J/MNRAS/427/1517
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a thorough analysis of multicolour CCD observations of two modulated RRab-type variables, XY And and UZ Vir. These Blazhko stars show relatively simple light-curve modulation with the usual multiplet structures in their Fourier spectra. One additional, independent frequency with linear-combination terms of the pulsation frequency is also detected in the residual spectrum of each of the two stars. The amplitude and phase relations of the triplet components are studied in detail. Most of the epoch-independent phase differences show a slight, systematic colour dependence. However, these trends have opposite signs in the two stars. The mean values of the global physical parameters and their changes with the Blazhko phase are determined, utilizing the inverse photometric method (IPM). The modulation properties and the IPM results are compared for the two variables. The pulsation period of XY And is the shortest when its pulsation amplitude is the highest, while UZ Vir has the longest pulsation period at this phase of the modulation. Despite this contrasting behaviour, the phase relations of the variations in their mean physical parameters are similar. These results do not agree with the predictions of the Blazhko model of Stothers.