- ID:
- ivo://CDS.VizieR/J/MNRAS/368/1757
- Title:
- Catalogue of RR Lyrae from NSVS
- Short Name:
- J/MNRAS/368/1757
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A search for RR Lyrae stars has been conducted in the publicly available data of the Northern Sky Variability Survey. Candidates have been selected by the statistical properties of their variation; the standard deviation, skewness and kurtosis with appropriate limits determined from a sample 314 known RRab and RRc stars listed in the General Catalogue of Variable Stars. From the period analysis and light-curve shape of over 3000 candidates 785 RR Lyrae have been identified of which 188 are previously unknown. The light curves were examined for the Blazhko effect and several new stars showing this were found. Six double-mode RR Lyrae stars were also found of which two are new discoveries. Some previously known variables have been reclassified as RR Lyrae stars and similarly some RR Lyrae stars have been found to be other types of variable, or not variable at all.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/548/A97
- Title:
- Catalogue of variable stars in open clusters
- Short Name:
- J/A+A/548/A97
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first catalogue of known variable stars in open cluster regions and with up to two times the given cluster radius. This gives basic information about the distribution of variable stars in cluster fields for the complete sky.
- ID:
- ivo://CDS.VizieR/J/AJ/98/2086
- Title:
- CCD photometry of NGC 2257 RR Lyrae
- Short Name:
- J/AJ/98/2086
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- B and V band CCD photometry is used to study 33 cluster and nine field RR Lyrae variables near the LMC cluster, NGC 2257. It is found that the mean magnitudes for the two groups differ by 0.17 mag. The cluster and field variables both have an Fe/H abundance ratio of -1.8+/-0.1. The results are compared used to compare NGC 2257 with galactic globular clusters, showing that NGC 2257 is indistinguishable from its local counterparts.
- ID:
- ivo://CDS.VizieR/J/AJ/112/618
- Title:
- CCD photometry of variable stars in M9
- Short Name:
- J/AJ/112/618
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- CCD observations have been used to derive precise light curves for six of the previously known RR Lyrae variables in the Oosterhoff type II globular cluster M9 and to search for additional variables. Nine variables have been discovered, eight of the RR Lyrae type. As a result, the total number of RR Lyrae variables has been revised from 9 to 17 (9 RRc and 8 RRab), the mean period of the RRc stars has been revised from 0.341d to 0.342d and that of the RRab stars from 0.621d to 0.638d. Simon's method that relates physical properties of RRc stars to the pulsation period and Fourier phase parameter {phi}_31_ has been used to determine the mass, luminosity, and temperature for one of the RRc stars. Published observations of RR Lyrae stars in M15 have been used to test Simon's method (1993ApJ...410..526S, 1993, IAUCo, 139, 315) and the results are promising. The formulae of Jurcsik and Kovacs (1996A&A...312..111J) for relating Fourier parameters of RRab stars to [Fe/H] have been used to derive a metal abundance for M9.
- ID:
- ivo://CDS.VizieR/II/162
- Title:
- CCD search for Cepheids in Crux and Centaurus
- Short Name:
- II/162
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog contains the results of a photometric survey for variable stars in a 9.4 square degree region along the galactic plane in Crux and Centaurus. A total of 300308 stars were observed at seven epochs over 42 days; 224 524 of these stars were detected at multiple epochs and were tested for possible variations in brightness that exceed observational error. 2422 stars are identified as variable at a formal confidence level of 99%; 270 of the new variables brighter than I=14.0 are classified as long period variables. A list of 242 likely short period variables with RMS amplitudes >=0.060mag is given. From this list, 37 Cepheid candidates were selected after inspection of their light curves.
- ID:
- ivo://CDS.VizieR/J/AJ/162/52
- Title:
- Census of variable stars toward Serpens Main
- Short Name:
- J/AJ/162/52
- Date:
- 14 Mar 2022 06:55:43
- Publisher:
- CDS
- Description:
- We monitored a 3deg^2^ area toward Serpens Main in the Pan-STARRS1 r, i, and z bands from 2016 April to September. Light curves of more than 11000 stars in each band were obtained, and 143 variables have been identified. Among those, 119 variables are new discoveries, while 24 variables were previously known. We present variability classes and periods of 99 stars. Of these, 81 are located in the upper giant branch, displaying long periods, while the remaining 18 variables are pre-main-sequence objects with short periods. We also identify eight eclipsing binary systems, including the known binary V0623Ser, and derive their physical parameters. According to a clustering analysis of Gaia DR2 stars in the observed field, there are 10 variable members in Serpens Main, where six members have been classified as young stellar objects in previous studies. Here we provide color-magnitude and color-color diagrams for these variables. The color variability of most variables in the color-magnitude diagrams produces the expected displacements, while the movements of cluster members point in different directions; this behavior may be associated with accretion spots or circumstellar disks.
- ID:
- ivo://CDS.VizieR/J/AJ/156/171
- Title:
- Cepheid abund.: multiphase results & spatial gradients
- Short Name:
- J/AJ/156/171
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Parameters and abundances have been derived for 435 Cepheids based on an analysis of 1127 spectra. Results from five or more phases are available for 52 of the program stars. The latter set of stars span periods between 1.5 and 68 days. The parameters and abundances show excellent consistency across phase. For iron, the average range in the determined abundance is 0.11 from these 52 stars. For 163 stars with more than one phase available the average range is 0.07. The variation in effective temperature tracks well with phase, as does the total broadening velocity. The gravity and microturbulent velocity follow phase, but with less variation and regularity. Abundance gradients have been derived using Gaia DR2 (Cat. I/345) parallax data, as well as Bayesian distance estimates based upon Gaia DR2 from Bailer-Jones et al. (2018, Cat. I/347). The abundance gradient derived for iron is d[Fe/H]/dR=-0.05 dex/kpc, similar to gradients derived in previous studies.
- ID:
- ivo://CDS.VizieR/J/ApJ/885/161
- Title:
- 90 cepheid candidates nearby NGC 6814
- Short Name:
- J/ApJ/885/161
- Date:
- 08 Mar 2022
- Publisher:
- CDS
- Description:
- We present a Cepheid-based distance to the nearby Seyfert galaxy NGC6814 from Hubble Space Telescope observations. We obtained F555W and F814W imaging over the course of 12 visits with logarithmic time spacing in 2013 August-October. We detected and made photometric measurements for 16469 unique sources across all images in both filters, from which we identify 90 excellent Cepheid candidates spanning a range of periods of 13-84days. We find evidence for incompleteness in the detection of candidates at periods <21days. Based on the analysis of Cepheid candidates above the incompleteness limit, we determine a distance modulus for NGC6814 relative to the LMC of {mu}_rel,LMC_=13.200_-0.031_^+0.031^mag. Adopting the recent constraint of the distance modulus to the LMC determined by Pietrzynski et al., we find m-M=31.677_-0.041_^+0.041^ which gives a distance of 21.65{+/-}0.41Mpc to NGC6814.
- ID:
- ivo://CDS.VizieR/J/A+A/659/A167
- Title:
- Cepheid Period-Wesenheit-Metallicity relation
- Short Name:
- J/A+A/659/A167
- Date:
- 23 Mar 2022 15:18:20
- Publisher:
- CDS
- Description:
- Classical Cepheids (DCEPs) represent a fundamental tool to calibrate the extragalactic distance scale. However, they are also powerful stellar population tracers, in the context of Galactic studies. The forthcoming Data Release 3 (DR3) of the Gaia mission will allow us to study with unprecedented detail the structure, the dynamics and the chemical properties of the Galactic disc, and in particular of the spiral arms, where most Galactic DCEPs reside. In this paper we aim at quantifying the metallicity dependence of the Galactic DCEPs Period-Wesenheit (PWZ) relation in the Gaia bands. We adopt a sample of 499 DCEPs with metal abundances from high-resolution spectroscopy, in conjunction with Gaia Early Data Release 3 parallaxes and photometry to calibrate a PWZ relation in the Gaia bands. We find a significant metallicity term, of the order of -0.5mag/dex, which is larger than the values measured in the NIR bands by different authors. Our best PWZ relation is W=(-5.988+/-0.018)-(3.176+/-0.044)(logP-1.0)-(0.520+/-0.090)[Fe/H]. We validate our PWZ relations by using the distance to the Large Magellanic Cloud as a benchmark, finding a very good agreement with the geometric distance provided by eclipsing binaries. As an additional test, we evaluate the metallicity gradient of the young Galactic disc, finding -0.0527+/-0.0022dex/kpc, in very good agreement with previous results.
- ID:
- ivo://CDS.VizieR/J/AJ/115/635
- Title:
- Cepheid radial velocities
- Short Name:
- J/AJ/115/635
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A catalog of Cepheid variables is used to probe the kinematics of the Galactic disk. Radial velocities are measured for eight distant Cepheids toward l=300{deg}; these new Cepheids provide a particularly good constraint on the distance to the Galactic center, R_0_. We model the disk with both an axisymmetric rotation curve and one with a weak elliptical component, and find evidence for an ellipticity of 0.043+/-0.016 near the Sun. Using these models, we derive R_0_=7.66+/-0.32kpc and v_circ_=237+/-12km/s. The distance to the Galactic center agrees well with recent determinations from the distribution of RR Lyrae variables and disfavors most models with large ellipticities at the solar orbit.
