- ID:
- ivo://CDS.VizieR/J/AJ/130/825
- Title:
- GALEX ultraviolet variability catalog
- Short Name:
- J/AJ/130/825
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present version 1.0 of the NASA Galaxy Evolution Explorer (GALEX) ultraviolet variability (GUVV) catalog, which contains information on 84 time-variable and transient sources gained with simultaneous near-ultraviolet (NUV) and far-ultraviolet (FUV) photometric observations. These time-variable sources were serendipitously revealed in the various 1.2{deg} diameter star fields currently being surveyed by the GALEX satellite in two ultraviolet bands (NUV 1750-2750{AA}, FUV 1350-1750{AA}) with limiting AB magnitudes of 23-25. The largest amplitude variable objects currently detected by GALEX are M dwarf flare stars, which can brighten by 5-10mag in both the NUV and FUV bands during short-duration (<500s) outbursts. Other types of large-amplitude ultraviolet variable objects include ab-type RR Lyrae stars, which can vary periodically by 2-5mag in the GALEX FUV band. This first GUVV catalog lists galactic positions and possible source identifications in order to provide the astronomical community with a list of time-variable objects that can now be repeatedly observed at other wavelengths.
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- ID:
- ivo://CDS.VizieR/J/A+A/343/847
- Title:
- Geneva Photometry of Eta Car
- Short Name:
- J/A+A/343/847
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We discuss 24yr of optical photometry of {eta} Carinae, among which new Geneva photometry made between 1994 and 1998. Various conclusions from our previous photometric studies are confirmed. The core hides a normal S Dor variable (or LBV): it shows light variations on a time scale of 1-4yr, with superimposed micro oscillations whose quasi-period indicates a temperature in the order of 22000K. Therefore, a more complicated model for {eta} Car is necessary to explain its extraordinary appearance and phenomena exhibited in the past and at present.
- ID:
- ivo://CDS.VizieR/J/A+A/415/241
- Title:
- Geneva photometry of HD 129929
- Short Name:
- J/A+A/415/241
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have gathered and analysed a timeseries of 1493 high-quality multicolour Geneva photometric data of the B3V {beta} Cep star Hd 129929. The dataset has a time base of 21.2 years. The occurrence of a beating phenomenon is evident from the data. We find evidence for the presence of at least six frequencies, among which we see components of two frequency multiplets with an average spacing of ~0.0121c/d which points towards very slow rotation. This result is in agreement with new spectroscopic data of the star and also with previously taken UV spectra. We provide the amplitudes of the six frequencies in all seven photometric filters. The metal content of the star is Z=0.018+/-0.004. All these observational results will be used to perform detailed seismic modelling of this massive star in a subsequent paper.
- ID:
- ivo://CDS.VizieR/J/A+A/449/305
- Title:
- Geneva photometry time series of HD 203664
- Short Name:
- J/A+A/449/305
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We made a seismic study of the young massive beta Cephei star HD 203664 with the goal of constraining its interior structure. Our study is based on a time series of 328 new Geneva 7-colour photometric data of the star spread over 496.8 days. The data confirm the frequency of the dominant mode of the star, which we refined to f_1_=6.02885c/d. The mode has a large amplitude of 37mmag in V and is unambiguously identified as a dipole mode (l=2) from its amplitude ratios and non-adiabatic computations. Besides f_1_, we discovered two additional new frequencies in the star with amplitudes above 4{sigma}: f_2_=6.82902c/d and f_3_=4.81543c/d, or one of their daily aliases. The amplitudes of these two modes are only between 3 and 4mmag, which explains why they were not detected before. Their amplitude ratios are too uncertain for mode identification. We show that the observed oscillation spectrum of HD 203664 is compatible with standard stellar models but that we have insufficient information for asteroseismic inferences. Among the large-amplitude beta Cephei stars, HD 203664 stands out as the only one rotating at a significant fraction of its critical rotation velocity (~40%).
275. GEOS RR Lyr survey
- ID:
- ivo://CDS.VizieR/J/other/IBVS/5767
- Title:
- GEOS RR Lyr survey
- Short Name:
- J/other/IBVS/576
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present here the sixth list of light maxima of RR Lyrae stars from the GEOS RR Lyr Survey, a GEOS program (http://www.upv.es/geos/) (Boninsegna et al., 2002ASPC..259..166B) of automated observations of RR Lyr stars started in January 2004.
- ID:
- ivo://CDS.VizieR/J/PAZh/22/269
- Title:
- Giant branch and variable stars in NGC 3201
- Short Name:
- J/PAZh/22/269
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Accurate equatorial coordinates have been determined for variable stars in the globular cluster NGC 3201. Results of photographic BV photometry are presented.
- ID:
- ivo://CDS.VizieR/J/A+A/446/773
- Title:
- GLMP sample of galactic OH/IR stars
- Short Name:
- J/A+A/446/773
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present optical and near-infrared finding charts taken from the DSS and 2MASS surveys of 94 IRAS sources selected from the GLMP catalogue, and accurate astrometry (~0.2") for most of them. Selection criteria were very red IRAS colours representative for OH/IR stars with optically thick circumstellar shells and the presence of variability according to the IRAS variability index (VAR>50). The main photometric properties of the stars in this `GLMP sample' are presented, discussed and compared with the correspondent properties of the `Arecibo sample' of OH/IR stars studied nearlier. We find that 37% of the sample (N=34) has no counterpart in the 2MASS, implying extremely high optical depths of their shells. Most of the sources identified in the 2MASS are faint (K>~8) and are of very red colour in the near-infrared, as expected. The brightest 2MASS counterpart (K=5.3mag) was found for IRAS18299-1705. Its blue colour H-K=1.3 suggests that IRAS18299-1705 is a post-AGB star. Few GLMP sources have faint but relatively blue counterparts. They might be misidentified field stars or stars that recently experienced a drop of their mass loss rates. The `GLMP sample' in general is made of oxygen-rich AGB stars, which are highly obscured by their circumstellar shells. They belong to the same population as the reddest OH/IR stars in the `Arecibo sample'.
- ID:
- ivo://CDS.VizieR/J/other/NewA/88.J1607
- Title:
- Globular cluster NGC 6397 variable stars
- Short Name:
- J/other/NewA/88.
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- We present a new time-series VI CCD photometry of the globular cluster NGC 6397, from which we obtained and analysed the light curves of 35 variables carefully identified in the cluster field. We assessed the membership of the variables with an astrometric analysis based on Gaia DR2 data. The cluster colour-magnitude diagram was differentially de- reddened and cleaned of non members, which allowed us to fit isochrones for [Fe/H]=-2.0dex in the range 13.0-13.5Gyr, for a mean reddening E(B-V)=0.19, and a distance of 2.5kpc. This distance was confirmed using the period-luminosity relation for the cluster's five SX Phoenicis variables (V10, V11, V15, V21, and V23) present among its blue stragglers, yielding 2.24+/-0.13kpc. We also modelled the light curves of four eclipsing binaries (V4, V5, V7, and V8), and gave the parameters of the systems; the contact binaries V7 and V8 have distances consistent with that of the cluster. NGC 6397 appears to harbour no RR Lyrae stars, being its horizontal branch remarkably blue, much like that of its analogous cluster, M10. To match the blue tail of the horizontal branch population, models of 0.64-0.66M_{sun}_ with mass loss at the RGB are required, indicating rather thin shell masses for horizontal branch stars.
- ID:
- ivo://CDS.VizieR/J/AJ/149/183
- Title:
- gri photometry of variables in NGC 4258
- Short Name:
- J/AJ/149/183
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results of a ground-based survey for Cepheid variables in NGC4258. This galaxy plays a key role in the Extragalactic Distance Scale due to its very precise and accurate distance determination via very long baseline interferometry observations of water masers. We imaged two fields within this galaxy using the Gemini North telescope and the Gemini Multi-Object Spectrograph, obtaining 16 epochs of data in the Sloan Digital Sky Survey gri bands over 4yr. We carried out point-spread function photometry and detected 94 Cepheids with periods between 7 and 127 days, as well as an additional 215 variables which may be Cepheids or Population II pulsators. We used the Cepheid sample to test the absolute calibration of theoretical gri Period-Luminosity relations and found good agreement with the maser distance to this galaxy. The expected data products from the Large Synoptic Survey Telescope should enable Cepheid searches out to at least 10Mpc.
- ID:
- ivo://CDS.VizieR/J/other/JAD/14.1
- Title:
- GSC04778-00152 photometry and spectroscopy
- Short Name:
- J/other/JAD/14.1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photometric and spectroscopic data of the southern contact binary GSC 04778-00152 are presented. Six new times of minimum are listed. For modelling purposes, we provide UBVRI phase diagrams of the contact binary with the contribution of the nearby companion removed.