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- ID:
- ivo://CDS.VizieR/J/MNRAS/466/392
- Title:
- UBVRICT1T2 photometry of 7 open clusters
- Short Name:
- J/MNRAS/466/392
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a comprehensive UBVRI and Washington CT_1_T_2_ photometric analysis of seven catalogued open clusters, namely: Ruprecht 3, 9, 37, 74, 150, ESO 324-15 and 436-2. The multiband photometric data sets in combination with 2MASS photometry and Gaia astrometry for the brighter stars were used to estimate their structural parameters and fundamental astrophysical properties. We found that Ruprecht 3 and ESO 436-2 do not show self-consistent evidence of being physical systems. The remained studied objects are open clusters of intermediate age (9.0<=log(t[yr^-1^])<=9.6), of relatively small size (r_cls_~0.4-1.3pc) and placed between 0.6 and 2.9kpc from the Sun. We analysed the relationships between core, half-mass, tidal and Jacoby radii as well as half-mass relaxation times to conclude that the studied clusters are in an evolved dynamical stage. The total cluster masses obtained by summing those of the observed cluster stars resulted to be ~10-15 per cent of the masses of open clusters of similar age located closer than 2kpc from the Sun. We found that cluster stars occupy volumes as large as those for tidally filled clusters.
- ID:
- ivo://CDS.VizieR/J/A+A/511/A25
- Title:
- UBVRIH{alpha} photometry of NGC6383
- Short Name:
- J/A+A/511/A25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The very young open cluster NGC 6383 centered on the O-star binary HD 159176 is an interesting place for studying the impact of early-type stars with strong radiation fields and powerful winds on the formation processes of low-mass stars. To investigate this process, it is necessary to determine the characteristics (age, presence, or absence of circumstellar material) of the population of low-mass pre-main-sequence (PMS) stars in the cluster. We obtained deep U B V Rc Ic H{alpha} photometric data of the entire cluster as well as medium-resolution optical spectroscopy of a subsample of X-ray selected objects. Our spectroscopic data reveal only very weak H{alpha} emission lines in a few X-ray selected PMS candidates. We photometrically identify a number of H-{alpha} emission candidates but their cluster membership is uncertain. We find that the fainter objects in the field of view have a wide range of extinction (up to A_V_=20), one X-ray selected OB star having A_V_~8. Our investigation uncovers a population of PMS stars in NGC 6383 that are probably coeval with HD 159176. In addition, we detect a population of reddened objects that are probably located at different depths within the natal molecular cloud of the cluster. Finally, we identify a rather complex spatial distribution of H{alpha} emitters, which is probably indicative of a severe contamination by foreground and background stars.
- ID:
- ivo://CDS.VizieR/J/A+A/402/549
- Title:
- UBVRIHalpha photometry of NGC 3293
- Short Name:
- J/A+A/402/549
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Deep and extensive CCD photometric observations at UBV(RI)cH{alpha} were carried out in the area of the open cluster NGC 3293. The new data set allows to see the entire cluster sequence down to Mv~+4.5, revealing that stars with Mv<-2 are evolving off the main sequence; stars with -2<Mv<+2 are located on the main sequence and stars with Mv>+2 are placed above it. According to our analysis, the cluster distance is d=2750+/-250pc (V0-Mv=12.2+/-0.2) and its nuclear age is 8+/-1Myr. NGC 3293 contains an important fraction of pre-main sequence (PMS) stars distributed along a parallel band to the ZAMS with masses from 1 to 2.5M_{sun}_ and a mean contraction age of 10Myr. This last value does not differ too much from the nuclear age estimate. If we take into account the many factors that may affect the PMS star positions on the colour-magnitude diagram, both ages can be perfectly reconciled. The star formation rate, on the other hand, suggests that NGC 3293 stars formed surely in one single event, therefore favouring a coeval process of star formation. Using the Halpha data, we detected nineteen stars with signs of Halpha emission in the region of NGC 3293, another indication that the star formation process is still active in the region. The computed initial mass function for the cluster has a slope of x=1.2+/-0.2, a bit flatter than the typical slope for field stars and similar to the values found for other young open clusters.
- ID:
- ivo://CDS.VizieR/J/AJ/114/2644
- Title:
- UBVRIHa photometry of NGC2264
- Short Name:
- J/AJ/114/2644
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- UBVRI H{alpha} CCD photometry has been obtained fro the young cluster NGC 2264. Using (R-H{alpha}) color, a measure of H{alpha} emission, we selected member stars in the pre-main sequence (PMS) stage.
- ID:
- ivo://CDS.VizieR/J/MNRAS/411/2530
- Title:
- UBVRIJHK photometry in NGC1624
- Short Name:
- J/MNRAS/411/2530
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a comprehensive multiwavelength analysis of the young cluster NGC 1624 associated with the HII region Sh2-212 using optical UBVRI photometry, optical spectroscopy and GMRT radio continuum mapping along with the near-infrared (NIR) JHK archival data.
- ID:
- ivo://CDS.VizieR/J/A+A/509/A104
- Title:
- UBVRIJHK photometry of Dolidze 25
- Short Name:
- J/A+A/509/A104
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The analysis of our deep UBVRIJHK photometry of Dolidze 25, located in the central area of the HII region Sh 2-284, reveals a young cluster with coeval MS and PMS populations of age 3.2-5Myr. The mass function for the optical PMS population in the mass range above 1.3-3.5M_{sun}_ is well fitted by a Salpeter mass function. On the other hand, the NIR photometry results indicate a large number of sources with H-Ks excess, practically distinct from the optical PMS candidate members. In addition, a distinctly older cluster member population of age 40Myr is suggested. The distance determined for the cluster from quantitative fits to ZAMS and isochrones (3.6kpc) is distinctly lower than previously published values. This result originates in the consistent use of low metallicity models for ZAMS fitting, applying published metallicity values for the cluster
- ID:
- ivo://CDS.VizieR/J/A+A/428/67
- Title:
- UBVRI mag of 3 Open Cluster Remnants candidates
- Short Name:
- J/A+A/428/67
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present CCD UBVI photometric and medium/high resolution spectroscopic observations obtained in the field of the previously unstudied dissolving open cluster candidates NGC 5385, NGC 2664 and Collinder 21. Our analysis is based on the discussion of star counts, photometry, radial velocity distribution, and proper motions available from the Tycho 2 catalogue (<I/259>). All three aggregates clearly emerge from the mean Galactic field, but, regrettably, the close scrutiny of proper motions and radial velocities reveals that we are not facing any physical group. Instead, what we are looking at are just chance alignments of a few bright unrelated stars. Our analysis casts some doubt on the Bica et al. (2001A&A...366..827B) criterion to look for Possible Open Cluster Remnants. It seems mandatory to define a better criterion to adopt for further investigations.
- ID:
- ivo://CDS.VizieR/J/MNRAS/401/621
- Title:
- UBVRI photometry in Be 15, Be 80 and NGC 2192
- Short Name:
- J/MNRAS/401/621
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The three open clusters Be 15, Be 80 and NGC 2192 have been observed using CCD UBV(RI)C photometry at the San Pedro Martir Observatory, Mexico within the framework of our open-cluster survey. The fundamental parameters of interstellar reddening, distance and age have been derived, and also the metallicity for NGC 2192 (solar metallicity has been assumed for the other two).
- ID:
- ivo://CDS.VizieR/J/A+AS/86/209
- Title:
- UBVRI photometry in cluster Tr 18
- Short Name:
- J/A+AS/86/209
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- UBVRI photoelectric photometry was obtained in the field of the open cluster Tr 18. From the analysis of the data we confirm that several distant OB stars were wrongly assumed as cluster members in previous investigations. The true distance modulus is 10.95, equivalent to a distance of 1550pc with the adopted age of (9.0+/-1.0)x10^7^yr. The GH Car Cepheid variable is very much probably a cluster member in view of its spatial position and the average absolute magnitude. However, some arguments are given to suggest that the reality of this cluster is still an open question. The observations in the Cousins system were carried out during 9 nights in April 1989 at Cerro Tololo Interamerican Observatory, with a single channel photometer attaéched to the 60cm Lowell telescope. The positions and identifications with large astrometric surveys was achieved by B. Skiff (Lowell Obs.) in 2010.