- ID:
- ivo://CDS.VizieR/J/A+A/471/165
- Title:
- UBVRI polarisation in NGC 5606
- Short Name:
- J/A+A/471/165
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present polarimetric observations in the UBVRI bands corresponding to 54 stars located in the direction of NGC 5606. Our intention is to analyze the dust characteristics between the Sun and the cluster, as well as to confirm doubtful memberships using polarimetric tools. We also want to determine if a group of 11 B and A stars identified in the past by Vazquez & Feinstein (1991A&AS...87..383V) in front of NGC 5606 has any physical entity. From polarimetric data we have found at least two dust layers along the line of sight to the open cluster.
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- ID:
- ivo://CDS.VizieR/J/A+A/409/933
- Title:
- UBVRI polarization in Stock 16
- Short Name:
- J/A+A/409/933
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present (UBVRI) multicolor linear polarimetric data for 26 of the brightest stars in the area of the open cluster Stock 16 that were considered to study the properties of the ISM (interstellar medium) towards the cluster. Our data yield a mean polarization percentage of P~2.5%, close to the polarization value produced by the ISM with normal efficiency (P_{lambda}_max_~5E_B-V_) undergoing a color excess of E_B-V_=0.51. The mean angle of the polarization vectors, {theta}=74.9deg, agrees quite well with the expected angle produced by dust particles aligned in the direction of the galactic disk (and the magnetic field) in the region. A study of the extinction suffered by the stars in the zone was also performed combining our new data with previous photometric data. In this sense, our analysis indicates that the visual absorption affecting Stock 16 stars is mainly produced in front of the cluster by a dust cloud at approximately 500 pc from the sun. The large polarization value of the non-member star, WR 51, confirms its background star nature.
- ID:
- ivo://CDS.VizieR/J/other/KFNT/22.231
- Title:
- UBVR photometry in NGC 6913
- Short Name:
- J/other/KFNT/22.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The CCD observations of a sky area in the NGC 6913 cluster were performed with the 2-meter telescope of the Terskol Peak Observatory (Northern Caucasus, Russian Federation). The magnitudes and coordinates of stars down to V=20mag were determined for a 7'x5' field. The equatorial coordinates of stars were obtained in the reference system of the USNO A2.0 catalog (Cat. <I/252>) with an accuracy of 0.35". The relationship between the instrumental photometric system and the Johnson UBVR system was derived.
- ID:
- ivo://CDS.VizieR/J/A+A/240/262
- Title:
- UBVR photometry of the open cluster King 2
- Short Name:
- J/A+A/240/262
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we present the Johnson-Cousins UBVR CCD photometry of the stars in King 2, an old open cluster towards the galactic anticenter. We have obtained the colour-magnitude diagram, the colour excess, the reddening, an estimate of the metallicity, and the distance modulus. The comparison of the observational colour-magnitude diagram with the theoretical simulations based on stellar models with convective overshoot shows that a major revision of the model structure is required. To this aim, we explore the possibility that the formulation of convective overshoot for stars in the mass range 1 to 2M_{sun}_ ought to be different from the one currently in use. The point of major uncertainty that we see to affect the stars in this domain is whether or not convective overshoot may erode the gradient in molecular weight in the regions surrounding the convective core. We find that models, in which this is not allowed to occur, better fit the overall morphology of the colour-magnitude diagram of King 2. In addition to this, analyzing the width of the main sequence band we suggest that a significant fraction of the stars are members of binary systems, and evaluate the range spanned by their mass ratios. Finally, we derive the luminosity function and the mass function for the main sequence stars of the cluster.
- ID:
- ivo://CDS.VizieR/J/A+A/372/477
- Title:
- ubvy{beta} photometry of h & chi Persei
- Short Name:
- J/A+A/372/477
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present uvby{beta} CCD photometry of the central region of the double cluster h&{chi} Persei. We identify =~350 stars, of which 214 were not included in Oosterhof's catalogue. Our magnitude limit V=16.5 allows us to reach early F spectral type and obtain very accurate fits to the ZAMS. We derive reddening values of E(b-y)=0.44+/-0.02 for h Persei and E(b-y)=0.39+/-0.05 for {chi} Persei. From the ZAMS fitting, we derive distance moduli V_0_-M_V_=11.66+/-0.20 and V_0_-M_V_=11.56+/-0.20 for h and {chi} Persei respectively. These values are perfectly compatible with both clusters being placed at the same distance and having identical reddenings. The shift in the main-sequence turnoff and isochrone fitting, however, show that there is a significant age difference between both clusters, with the bulk of stars in h Persei being older than {chi} Persei. There is, however, a significant population of stars in h Persei which are younger than {chi} Persei. All this argues for at least three different epochs of star formation, corresponding approximately to logt=7.0, 7.15 and 7.3.
- ID:
- ivo://CDS.VizieR/J/other/RMxAA/44.111
- Title:
- ubvy{beta} photometry of NGC 6882/5 stars
- Short Name:
- J/other/RMxAA/44
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Unpublished uvby-{beta} photoelectric photometry of the open cluster NGC 6882/5 is presented. Utilizing already tested distance determinations through photometric techniques, it is found that there are at least two distinct star accumulations in the direction of the open cluster NGC 6882/5. A brief discussion is made of the nature of the previously found short period variables.
- ID:
- ivo://CDS.VizieR/J/AcA/59/69
- Title:
- ubvy{beta} photometry of stars in NGC 7062
- Short Name:
- J/AcA/59/69
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report results of spectroscopic and photometric observations of ten delta Sct stars and one eclipsing binary in the open cluster NGC 1817, and of ten delta Sct stars and two other variables in the open cluster NGC 7062. For all targets in NGC 1817 and for three targets in NGC 7062 the radial velocity and projected rotational velocity are determined. For all stars the effective temperature and surface gravity is measured.
- ID:
- ivo://CDS.VizieR/J/A+A/426/827
- Title:
- ubvyH{beta} photometry in NGC 1817 / 1807
- Short Name:
- J/A+A/426/827
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalogue of accurate uvby-H{beta} and J2000 coordinates for 7842 stars in an area of 65'x40' around NGC 1817. We mark the selection of probable members of NGC 1817, combining this photometric study with the previous astrometric analysis (Balaguer-Nunez et al. 2004, Cat. <J/A+A/426/819>). Also given is the cross-identification of stars in common with the astrometry (Balaguer-Nunez et al. 2004, Cat. <J/A+A/426/819>), WEBDA (http://obswww.unige.ch/WEBDA), Hipparcos (ESA, 1997, Cat. <I/239>), Tycho-2 (Hog et al., 2000, Cat. <I/250>) and USNO-A2 (Monet et al., 1998, Cat. <I/252>) catalogues.
- ID:
- ivo://CDS.VizieR/J/A+A/525/A16
- Title:
- ubvy light curves of CP stars in open clusters
- Short Name:
- J/A+A/525/A16
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photometric variability of chemically peculiar (CP) stars of the upper main sequence is closely connected to their local stellar magnetic field and their rotational period. Long term investigations, as presented here, help us to identify possible stellar cycles (as in the Sun). Photoelectric Stroemgren uvby time series for 27 CP stars within the boundaries of open clusters are presented. Our observations cover a time period of about six years (1986 to 1992) with typically fifteen measurements for each objects. These observations help us to determine the rotational periods of these objects. We established, for the first time, variability for fourteen CP stars. For additional two stars, a merging of already published data sets, resulted in more precise periods, whereas for six objects, the published periods could be confirmed. Last, but not least, no significant variations were found for five stars. Apart from six stars, all targets seem to be members of their host open clusters.
- ID:
- ivo://CDS.VizieR/J/MNRAS/478/5184
- Title:
- UCAC5 open clusters membership and proper motion
- Short Name:
- J/MNRAS/478/5184
- Date:
- 10 Dec 2021 14:08:57
- Publisher:
- CDS
- Description:
- We present mean proper motions and membership probabilities of individual stars for optically visible open clusters, which have been determined using data from the UCAC5 catalogue. This follows our previous studies with the UCAC2 and UCAC4 catalogues, but now using improved proper motions in the GAIA reference frame. In the present study results were obtained for a sample of 1108 open clusters. For five clusters, this is the first determination of mean proper motion, and for the whole sample, we present results with a much larger number of identified astrometric member stars than on previous studies. It is the last update of our Open cluster Catalogue based on proper motion data only. Future updates will count on astrometric, photometric and spectroscopic GAIA data as input for analyses.