- ID:
- ivo://CDS.VizieR/J/MNRAS/309/739
- Title:
- NGC 2660 UBVIc photometry
- Short Name:
- J/MNRAS/309/739
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present CCD UBVI photometry of the intermediate old open cluster NGC 2660, covering from the red giant region to about seven magnitudes below the main sequence turn-off. Using the synthetic colour-magnitude diagram method, we estimate in a self-consistent way values for distance modulus [(m-M)_0_~12.2], reddening [E(B-V)~0.40], metallicity ([Fe/H] about solar) and age (t<=1Gyr). A 30 per cent population of binary stars turns out to be probably present.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/115/734
- Title:
- NGC 6231 UBVRI and H{alpha} photometry
- Short Name:
- J/AJ/115/734
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- UBVRI and H{alpha} CCD photometry has been obtained for the young open cluster NGC 6231. From the R-H{alpha} color, a measure of the H{alpha} emission, we find 12 pre-main-sequence (PMS) members and seven possible PMS members in the cluster. Applying recent stellar evolutionary tracks and PMS evolutionary tracks, we derive the age, age spread, and initial mass function of the cluster. The initial mass function of NGC 6231 is a Gaussian with a turnover at logm~0.4 (m~2.5M_{Sun}_) and shows an abrupt decrease in the number of low-mass stars. Possible reasons for the suppression of low-mass star formation and star formation processes are discussed.
- ID:
- ivo://CDS.VizieR/J/MNRAS/453/1095
- Title:
- NGC 6866 UBVRI photometry
- Short Name:
- J/MNRAS/453/1095
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present CCD UBVRI photometry of the field of the open cluster NGC 6866. Structural parameters of the cluster are determined utilizing the stellar density profile of the stars in the field. We calculate the probabilities of the stars being physical members of the cluster, using their astrometric data, and perform further analyses using only the most probable members. The reddening and metallicity of the cluster were determined by independent methods. The LAMOST spectra and the ultraviolet excess of the F- and G-type main-sequence stars in the cluster indicate that the metallicity of the cluster is about the solar value. We estimated the reddening E(B-V)=0.074+/-0.050mag using the U-B versus B-V two-colour diagram. The distance modula, the distance and the age of NGC 6866 were derived as {mu}=10.60+/-0.10mag, d=1189+/-75pc and t=813+/-50Myr, respectively, by fitting colour-magnitude diagrams of the cluster with the PARSEC isochrones. The Galactic orbit of NGC 6866 indicates that the cluster is orbiting in a slightly eccentric orbit with e=0.12. The mass function slope x=1.35+/-0.08 was derived by using the most probable members of the cluster.
- ID:
- ivo://CDS.VizieR/J/A+A/616/A124
- Title:
- NGC 3105 UBVR photometry
- Short Name:
- J/A+A/616/A124
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- NGC 3105 is a young open cluster hosting blue, yellow, and red supergiants. This rare combination makes it an excellent laboratory for constraining evolutionary models of high-mass stars. It has been poorly studied, and the fundamental parameters such as its age or distance are not well defined. We intend to characterise in an accurate way the cluster and its evolved stars, for which we derive for the first time atmospheric parameters and chemical abundances. We performed a complete analysis combining UBVR photometry with spectroscopy. We obtained spectra with classification purposes for 14 blue stars and high-resolution spectroscopy for an in-depth analysis of the six other evolved stars. We identify 126 B-type likely members within a radius of 2.7+/-0.6arcmin, which implies an initial mass, Mcl~=4100M_{sun}_. We find a distance of 7.2+/-0.7kpc for NGC 3105, placing it at R_GC_=10.0+/-1.2kpc. Isochrone fitting supports an age of 28+/-6Ma, implying masses around 9.5M_{aun}_ for the supergiants. A high fraction of Be stars (~25%) is found at the top of the main sequence down to spectral type b3. From the spectral analysis we estimate for the cluster an average v_rad_=+46.9+/-0.9km/s and a low metallicity, [Fe/H]=-0.29+/-0.22. We also have determined, for the first time, chemical abundances for Li, O, Na, Mg, Si, Ca, Ti, Ni, Rb, Y, and Ba for the evolved stars. The chemical composition of the cluster is consistent with that of the Galactic thin disc. An overabundance of Ba is found, supporting the enhanced s-process. NGC 3105 has a low metallicity for its Galactocentric distance, comparable to typical LMC stars. It is a valuable spiral tracer in a very distant region of the Carina-Sagittarius spiral arm, a poorly known part of the Galaxy. As one of the few Galactic clusters containing blue, yellow, and red supergiants, it is massive enough to serve as a test bed for theoretical evolutionary models close to the boundary between intermediate- and high-mass stars.
- ID:
- ivo://CDS.VizieR/J/ApJ/670/516
- Title:
- NGC 2547 4.5-8um photometry
- Short Name:
- J/ApJ/670/516
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have surveyed the 30Myr old cluster NGC 2547 for planetary debris disks using Spitzer. At 4.5-8um we are sensitive to the photospheric level down to mid-M stars (0.2M_{sun}_), and at 24um to early G stars (1.2M_{sun}_).
- ID:
- ivo://CDS.VizieR/J/A+A/437/457
- Title:
- NGC 2548 uvbyH{beta} and proper motions
- Short Name:
- J/A+A/437/457
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Deep CCD photometry in the uvby-H{beta} intermediate-band system is presented for the cluster NGC 2548 (M 48). A complete membership analysis based on astrometric and photometric criteria is applied.
- ID:
- ivo://CDS.VizieR/J/A+A/470/585
- Title:
- NGC 2682 uvby-Hbeta photometry
- Short Name:
- J/A+A/470/585
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Following deep astrometric and photometric study of the cluster NGC 2682 (M 67), we are able to accurately determine its fundamental parameters. Being an old and rich cluster, M 67 is relevant for the analysis of the Galactic disk evolution. M 67 is well studied but lacks a wide and deep Stroemgren photometric study. The brightest stars of the open cluster M 67 were used as uvby-Hbeta standard stars in our studies of NGC 1817 and NGC 2548, and the extension of the field covered, as well as the number of observations, allowed us to obtain the best set of Stroemgren data ever published for this cluster. We discuss the results of our CCD uvby-Hbeta intermediate-band photometry, covering an area of about 50'x50' down to V~19. Moreover, a complete membership segregation based on astrometric and photometric criteria is obtained. The photometric analysis of a selected sample of stars yields a reddening value of E(b-y)=0.03+/-0.03, a distance modulus of V_0_-M_V_=9.7+/-0.2 and [Fe/H]=0.01+/-0.14. Through isochrone fitting we found an age of logt=9.6+/-0.1 (4.2+/-0.2Gyr). A clump of approximately 60 stars around V=16, (b-y)=0.4 could be interpreted as a population of pre-cataclysmic variable stars (if members), or as a stream of field G-type stars placed at twice the distance of the cluster (if non-members).
- ID:
- ivo://CDS.VizieR/J/MNRAS/419/2379
- Title:
- NGC 6866 variables V and I light curves
- Short Name:
- J/MNRAS/419/2379
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results of a variability search in the intermediate-age open cluster NGC 6866 from 29 nights over two observing seasons. We find 28 periodic variables, of which 19 are newly identified. The periods of these variables, which have V magnitudes from 11.5 to 19.3mag, range from ~48min to 37d. We detected several {delta} Scuti stars, some of which are of high amplitude, as well as {gamma} Doradus and rotational variables, and eclipsing binaries. In order to study the physical properties of the cluster, we obtained UBVRI photometry of all the stars on a good photometric night. The radial distribution of the stellar surface density shows that the cluster has a radial extent of about 7-arcmin ( ~3pc) with a peak density of 5.7+/-0.7stars/arcmin^2^ at the cluster centre. The colour-colour diagram indicates a reddening of E(B-V)=0.10mag towards NGC 6866. A distance of ~1.47kpc and an age of ~630Myr are estimated from the colour-magnitude diagram using the theoretical isochrones of solar metallicity.
- ID:
- ivo://CDS.VizieR/J/BaltA/12/323
- Title:
- NGC 1750 + 1758 Vilnius photometry
- Short Name:
- J/BaltA/12/323
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Seven-color photometry in the Vilnius system has been obtained for 420 stars down to V=16mag in the area containing the overlapping open clusters NGC 1750 and NGC 1758 in Taurus. Spectral and luminosity classes, color excesses, interstellar extinctions and distances are given for 287 stars. The classification of stars is based on their reddening-free Q-parameters. 18 stars observed photoelectrically were used as standards.
- ID:
- ivo://CDS.VizieR/J/BaltA/20/27
- Title:
- NGC 752 Vilnius photometry
- Short Name:
- J/BaltA/20/27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have performed multicolor CCD observations of the central area of NGC 752 to search for faint, low-mass members of this open cluster. Four 12'x12' fields were taken on the 1.8m Vatican Advanced Technology Telescope (Mt. Graham, Arizona) using a 4K CCD camera and eight intermediate-band filters of the Stromvil (Stromgren + Vilnius) system. In this paper we present a catalog of photometry for 405 stars down to the limiting magnitude V=18.5, which contains V magnitudes and color indices of the Vilnius system, together with photometric determinations of spectral types, absolute magnitudes MV , interstellar reddening values E(Y-V) and metallicity parameters [Fe/H]. The good quality multicolor data made it possible to identify the locus of the lower main sequence to four magnitudes beyond the previous (photographic) limit. A relatively small number of photometric members identified at faint magnitudes seems to be indicative of actual dissolution of the cluster from the low-mass end.
