<i>UBVRI</i> imaging photometry of the open cluster Cr 272

Vazquez, R. A.; Baume, G.; Feinstein, A.; Prado, P.

doi:10.1051/aas:1997176

Cited by 63 publications

(120 citation statements)

References 6 publications

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“…Similarly to other regions with anomalous extinction laws (eg. Trumpler 16 or Trumpler 14 Vazquez et al 1996), we find stars belonging to both groups and to the field affected by normal and anomalous extinction, as if some of them were strongly affected by the denser interstellar medium while others were not. For some sources, the anomalies will be the result of circum-stellar envelopes, as is the case of star FM3060a -No 14 in our notation-which is surrounded by a ionized hydrogen veil (Moreno-Corral et al 2005).…”

Section: Haffner 18mentioning

confidence: 71%

Open clusters in the Third Galactic Quadrant III. Alleged binary clusters

Vazquez

Moitinho

Carraro³

et al. 2010

A&A

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Aims. We aim to determine accurate distances and ages of eight open clusters in order to: (1) assess their possible binarity (2) provide probes to trace the structure of the Third Galactic Quadrant. Methods. Cluster reddenings, distances, ages and metallicities are derived from ZAMS and isochrone fits in UBVRI photometric diagrams. Field contamination is reduced by restricting analysis to stars within the cluster limits derived from star counts. Further membership control is done by requiring that stars have consistent positions in several diagrams and by using published spectral types. Results. The derived distances, ages and metallicities have shown that none of the analysed clusters compose binary/double systems. Of the four candidate pairs, only NGC 2383/NGC 2384 are close to each other, but have different metallicities and ages. Ruprecht 72 and Ruprecht 158 are not clusters but fluctuations of the field stellar density. Haffner 18 is found to be the superposition of two stellar groups at different distances: Haffner 18(1) at 4.5 kpc and Haffner 18(2) between 9.5 and 11.4 kpc from the Sun. The derived distances and ages have been used to situate the clusters in the Galactic context. In particular, young stellar groups trace spiral structure at large Galactocentric radii. At least two clusters formed during the last few 10 8 yr in an interstellar medium with less than solar abundances. Conclusions. In contrast with the LMC, double clusters are apparently rare, or even non existent, in the undisturbed environment of the Third Galactic Quadrant. This leaves open the question of whether binary clusters form more easily toward denser and more violent regions of the Milky Way such as the inner Galaxy.

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Section: Haffner 18mentioning

confidence: 71%

Open clusters in the Third Galactic Quadrant III. Alleged binary clusters

Vazquez

Moitinho

Carraro³

et al. 2010

A&A

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“…Previous investigations by our group (Vázquez et al 1996;Baume et al 2003) presented optical observations (typically UBVRI) of young star clusters and star forming regions. To reduce the uncertainties, we complement these UBVRI data with H α photometry, kinematic information, and near/mid infrared data.…”

Section: Discussionmentioning

confidence: 99%

The Ara OB1a association

Baume

Carraro²,

Comerón³

et al. 2011

A&A

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Context. The Ara OB1a association is a nearby complex in the fourth Galactic quadrant where a number of young/embedded star clusters are projected close to more evolved, intermediate age clusters. It is also rich in interstellar matter, and contains evidence of the interplay between massive stars and their surrounding medium, such as the rim HII region NGC 6188. Aims. We provide robust estimates of the fundamental parameters (age and distance) of the two most prominent stellar clusters, NGC 6167 and NGC 6193, that may be used as a basis for studing the star formation history of the region. Methods. The study is based on a photometric optical survey (UBVIH α ) of NGC 6167 and NGC 6193 and their nearby field, complemented with data from 2MASS-VVV, UCAC3, and IRAC-Spitzer in this region. Results. We produce a uniform photometric catalogue and estimate more robustly the fundamental parameters of NGC 6167 and NGC 6193, in addition to the IRAS 16375-4854 source. As a consequence, all of them are located at approximately the same distance from the Sun in the Sagittarius-Carina Galactic arm. However, the ages we estimate differ widely: NGC 6167 is found to be an intermediate-age cluster (20-30 Myr), NGC 6193 a very young one (1-5 Myr) with PMS, H α emitters and class II objects, and the IRAS 16375-4854 source is the youngest of the three containing several YSOs. Conclusions. These results support a picture in which Ara OB1a is a region where star formation has proceeded for several tens of Myr until the present. The difference in the ages of the different stellar groups can be interpreted as a consequence of a triggered star formation process. In the specific case of NGC 6193, we find evidence of possible non-coeval star formation.

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“…Differences in distance can partially account for diverse estimates of mass and structural parameters. Its mass was first estimated to be 2000 M (Vazquez et al 1996). However, the photometry used A&A 515, A26 (2010) by these authors barely reached the turn-on point of the pre-main sequence (PMS), while they extrapolated the mass assuming a Salpeter initial mass function (IMF).…”

Section: Introductionmentioning

confidence: 99%

A MAD view of Trumpler 14

Sana

Momany

Gieles³

et al. 2010

A&A

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We present adaptive optics (AO) near-infrared observations of the core of the Tr 14 cluster in the Carina region obtained with the ESO multi-conjugate AO demonstrator, MAD. Our campaign yields AO-corrected observations with an image quality of about 0.2 across the 2 field of view, which is the widest AO mosaic ever obtained. We detected almost 2000 sources spanning a dynamic range of 10 mag. The pre-main sequence (PMS) locus in the colour−magnitude diagram is well reproduced by Palla & Stahler isochrones with an age of 3 to 5 × 10 5 yr, confirming the very young age of the cluster. We derive a very high (deprojected) central density n 0 ∼ 4.5(±0.5) × 10 4 pc −3 and estimate the total mass of the cluster to be about ∼4.3 +3.3 −1.5 × 10 3 M , although contamination of the field of view might have a significant impact on the derived mass. We show that the pairing process is largely dominated by chance alignment so that physical pairs are difficult to disentangle from spurious ones based on our single epoch observation. Yet, we identify 150 likely bound pairs, 30% of these with a separation smaller than 0.5 (∼1300 AU). We further show that at the 2σ level massive stars have more companions than lower-mass stars and that those companions are respectively brighter on average, thus more massive. Finally, we find some hints of mass segregation for stars heavier than about 10 M . If confirmed, the observed degree of mass segregation could be explained by dynamical evolution, despite the young age of the cluster.

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UBVRI imaging photometry of the open cluster Cr 272

Cited by 63 publications

References 6 publications

Open clusters in the Third Galactic Quadrant III. Alleged binary clusters

Open clusters in the Third Galactic Quadrant III. Alleged binary clusters

The Ara OB1a association

A MAD view of Trumpler 14

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