- ID:
- ivo://CDS.VizieR/J/A+A/391/179
- Title:
- UBV CCD photometry of NGC 1220
- Short Name:
- J/A+A/391/179
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present UBV CCD observations obtained in the field of the northern open cluster NGC 1220, for which little information is available. We provide also BV CCD photometry of a field 5' northward of NGC 1220 to take into account field star contamination. We argue that NGC 1220 is a young compact open cluster, for which we estimate a core radius in the range 1.5-2.0arcmin. We identify 26 likely candidate members with spectral type earlier than A5, down to V_0_=15.00mag on the basis of the position in the two-colour Diagram and in the Colour Magnitude Diagrams (CMDs). By analyzing the distribution of these stars in the colour-colour and CMDs, we find that NGC 1220 has a reddening E(B-V)=0.70+/-0.15mag, is placed 1800+/-200pc distant from the Sun, and has an age of about 60Myrs. The cluster turns out to be located about 120pc above the Galactic plane, relatively high with respect to its age.
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- ID:
- ivo://CDS.VizieR/II/37
- Title:
- UBV HR Diagrams of Globular Clusters
- Short Name:
- II/37
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- UBV observations of over 37,000 stars have been compiled from the literature to yield 165 color-magnitude diagrams. There is a list of bibliographic references for each cluster diagram.
- ID:
- ivo://CDS.VizieR/J/AJ/145/37
- Title:
- UBVI and H{alpha} CCD photometry of NGC 6231
- Short Name:
- J/AJ/145/37
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have performed new wide-field photometry of the young open cluster NGC6231 to study the shape of the initial mass function (IMF) and mass segregation. We also investigated the reddening law toward NGC6231 from optical to mid-infrared color excess ratios, and found that the total-to-selective extinction ratio is R_V_=3.2, which is very close to the normal value. But many early-type stars in the cluster center show large color excess ratios. We derived the surface density profiles of four member groups, and found that they reach the surface density of field stars at about 10', regardless of stellar mass. The IMF of NGC6231 is derived for the mass range 0.8-45M_{sun}_. The slope of the IMF of NGC6231 ({Gamma}=-1.1+/-0.1) is slightly shallower than the canonical value, but the difference is marginal. In addition, the mass function varies systematically, and is a strong function of radius-it is very shallow at the center, and very steep at the outer ring suggesting the cluster is mass segregated. We confirm the mass segregation for the massive stars (m>~8 M_{sun}_) by a minimum spanning tree analysis. Using a Monte Carlo method, we estimate the total mass of NGC6231 to be about 2.6(+/-0.6)*10^3^M_{sun}_. We constrain the age of NGC 6231 by comparison with evolutionary isochrones. The age of the low-mass stars ranges from 1 to 7Myr with a slight peak at 3Myr. However, the age of the high-mass stars depends on the adopted models and is 3.5+/-0.5Myr from the non-rotating or moderately rotating models of Brott et al. (2011, cat. J/A+A/530/A115) as well as the non-rotating models of Ekstrom et al. (2012, cat. J/A+A/537/A146). But the age is 4.0-7.0Myr if the rotating models of Ekstrom et al. (2012, cat. J/A+A/537/A146) are adopted. This latter age is in excellent agreement with the timescale of ejection of the high-mass runaway star HD153919 from NGC6231, albeit the younger age cannot be entirely excluded.
- ID:
- ivo://CDS.VizieR/J/A+A/416/537
- Title:
- UBVI and HST photometry of young stellar clusters
- Short Name:
- J/A+A/416/537
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- These tables contain a combination of ground-based and HST archive data for stellar clusters in 18 nearby spiral galaxies. Structural parameters for each cluster are measured on HST images, while UBVI photometry is from ground-based data obtained with the Danish 1.54m telescope at ESO La Silla, the 2.56m Nordic Optical Telescope in La Palma, Canary Islands, and the 3m Shane Telescope at Lick Observatory, California. Photometry in the STMAG system based on the HST data is also given (table 7) for each cluster for the available bandpasses.
- ID:
- ivo://CDS.VizieR/J/A+A/407/919
- Title:
- UBVI and JHK photometry in Lindsay 1
- Short Name:
- J/A+A/407/919
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Results of UBVI stellar photometry of SMC star cluster Lindsay 1. The frames were obtained in October 1999 with the 1.3m Warsaw telescope, Las Campanas Observatory with the 2048x2048 CCD camera. Missing magnitudes and colors of the stars are replaced with value 100.00.
- ID:
- ivo://CDS.VizieR/J/A+A/407/527
- Title:
- UBVIc and JHK photometry of NGC 1582 and NGC 1663
- Short Name:
- J/A+A/407/527
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present CCD UBV(I)c observations obtained in the field of the previously unstudied northern open clusters NGC 1582 and NGC 1663. For the former, we also provide high-resolution spectra of the brightest stars and complement our data with Two-Micron All Sky-Survey (2MASS) near-infrared photometry and with astrometric data from the Tycho-2 catalog. From the analysis of all these data, we argue that NGC 1582 is a very poor, quite large and heavily contaminated open cluster. It turns out to have a reddening E(B-V)=0.35+/-0.03, to be situated 1100+/-100pc from the Sun and to have an age of 300+/-100Myr. On the other hand, we were not able to unambiguously clarify the nature of NGC 1663. By assuming it is a real cluster and from the analysis of its photometric diagrams, we found a color excess value E(B-V)=0.20, an intermediate age value (~2000Myr) and a distance of about 700pc. The distribution of the stars in the region however suggests we are probably facing an open cluster remnant. As an additional result, we obtained aperture photometry of three previously unclassified galaxies placed in the field of NGC 1663 and performed a preliminary morphological classification of them.
- ID:
- ivo://CDS.VizieR/J/AJ/143/41
- Title:
- UBVIc CCD photometry of star clusters Tr14 and Tr16
- Short Name:
- J/AJ/143/41
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new UBVIc CCD photometry of the young open clusters Trumpler 14 (Tr 14) and Trumpler 16 (Tr 16) in the {eta} Carina Nebula (NGC 3372). We also identify the optical counterpart of Chandra X-ray sources and Two Micron All Sky Survey point sources. The members of the clusters were selected from the proper-motion study, spectral types, reddening characteristics, and X-ray or near-IR excess emission. An abnormal reddening law R_V,cl_=4.4+/-0.2 was obtained for the stars in the {eta} Carina Nebula using the 141 early-type stars with high proper-motion membership probability (P_{mu}_>=70%). We determined the distance to each cluster and conclude that Tr 14 and Tr 16 have practically the same distance modulus of V_0_-M_V_=12.3+/-0.2mag (d=2.9+/-0.3kpc). The slope of the initial mass function was determined to be {Gamma}=-1.3+/-0.1 for Tr 14, {Gamma}=-1.3+/-0.1 for Tr 16, and {Gamma}=-1.4+/-0.1 for all members in the observed region for the stars with log m>=0.2. We also estimated the age of the clusters to be about 1-3Myr from the evolutionary stage of evolved stars and low-mass pre-main-sequence stars.
- ID:
- ivo://CDS.VizieR/J/A+A/381/884
- Title:
- UBVI CCD photometry in NGC 2571
- Short Name:
- J/A+A/381/884
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- CCD UBVI imaging photometry was carried out in the field of the open cluster NGC 2571. From the analysis of our data we state the cluster is at a distance of 1380+/-130pc and its age is 50+/-10x10^6yr. The cluster mass function has a slope larger than a typical Salpeter's law. There are two notorious features in NGC 2571: the cluster contains a high proportion of stars located below the reference line that are serious candidates to be metallic line stars (probably Am-Fm), and shows also a sharp gap along its main sequence that cannot be explained by a random process nor by a biased rejection of cluster members. A striking blue object was detected in the cluster field that could be a white dwarf candidate. We carried out CCD imaging photometry in the Kron-Cousins UBVI system on April 27 and 29, 1994 using a 1024x1024pix CCD with a scale of 0.37"/pix and a field of view of 6.3'x6.3' attached to the 1.54-m Danish telescope at ESO, La Silla, Chile.
- ID:
- ivo://CDS.VizieR/J/MNRAS/341/805
- Title:
- UBVI CCD photometry of Cep OB3b
- Short Name:
- J/MNRAS/341/805
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of a low-mass pre-main-sequence (PMS) stellar population in the younger subgroup of the Cepheus OB3 association, Cep OB3b, using UBVI CCD photometry and follow-up spectroscopy. The optical survey covers approximately 1300arcmin^2^ on the sky and gives a global photometric and astrometric catalogue for more than 7000 objects. The location of a PMS population is well defined in a V versus (V-I) colour-magnitude diagram.
- ID:
- ivo://CDS.VizieR/J/MNRAS/310/982
- Title:
- UBVI CCD Photometry of M11 - II.
- Short Name:
- J/MNRAS/310/982
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This directory contains Johnson-Cousins UBVI photometric data for M11 (NGC 6705) and a neighboring field (around PN G027.4-03.5). The photometric data for M11 are tightly matched to the SAAO E-region standard system (Menzies et al. SAAO Circ., 1989SAAOC..13....1M; Menzies et al., 1991MNRAS.248..642M; Kilkenny et al., 1998MNRAS.294...93K). For the PN G027.4-03.5 region, the standard system of Landolt (1992, Cat. <II/183>) was used and small systematic difference in photometry between the two tables may be present, in particular in (U-B). Table 2 contains UBVI data for 14,179 stars brighter than V=17mag in M11 (about 40arcmin x 40arcmin region). The star numbers and proper motion memberships by McNamara et al. (1977A&AS...27..117M) and Su et al. (1998, Cat. <J/A+AS/128/255>) are also identified and included. Table 3 contains UBVI data for 3,676 stars around PN G027.4-03.5.
