scholarly journals A new look at Sco OB1 association with Gaia DR2

2020 ◽  
Vol 495 (1) ◽  
pp. 1349-1359 ◽  
Author(s):  
L Yalyalieva ◽  
G Carraro ◽  
R Vazquez ◽  
L Rizzo ◽  
E Glushkova ◽  
...  
Keyword(s):  
Open Cluster ◽  
Three Dimensional ◽  
Star Formation History ◽  
Optical Data ◽  
Dimensional Structure ◽  
Fundamental Parameters ◽  
Time Estimates ◽  
Young Open Cluster ◽  
Pms Stars ◽  
Gaia Dr2

ABSTRACT We present and discuss photometric optical data in the area of the OB association Sco OB1 covering about 1 deg2. UBVI photometry is employed in tandem with Gaia DR2 data to investigate the three-dimensional structure and the star formation history of the region. By combining parallaxes and proper motions, we identify seven physical groups located between the young open cluster NGC 6231 and the bright nebula IC 4628. The most prominent group coincides with the sparse open cluster Trumpler 24. We confirm the presence of the intermediate-age star cluster VdB-Hagen 202, which is unexpected in this environment, and provide for the first time estimates of its fundamental parameters. After assessing individual groups membership, we derive mean proper motion components, distances, and ages. The seven groups belong to two different families. To the younger family (family I) belong several pre-main-sequence (PMS) stars as well. These are evenly spread across the field, and also in front of VdB-Hagen 202. VdB-Hagen 202, and two smaller, slightly detached, groups of similar properties form family II, which do not belong to the association, but are caught in the act of passing through it. As for the younger population, this forms an arc-like structure from the bright nebula IC 4628 down to NGC 6231, as previously found. Moreover, the PMS stars density seems to increase from NGC 6231 northward to Trumpler 24.

scholarly journals Star formation in the outer Galaxy: membership and fundamental parameters of the young open cluster NGC 1893

2011 ◽  
Vol 527 ◽  
pp. A77 ◽  
Author(s):  
L. Prisinzano ◽  
J. Sanz-Forcada ◽  
G. Micela ◽  
M. Caramazza ◽  
M. G. Guarcello ◽  
...  
Keyword(s):  
Star Formation ◽  
Open Cluster ◽  
Fundamental Parameters ◽  
Young Open Cluster

Investigation of the nearby open clusters with Gaia DR2 data

2019 ◽  
Vol 14 (S351) ◽  
pp. 502-506
Author(s):  
Anton F. Seleznev ◽  
Vladimir M. Danilov ◽  
Giovanni Carraro
Keyword(s):  
Three Dimensional ◽  
Open Clusters ◽  
Dimensional Structure ◽  
Proper Motions ◽  
Membership Probability ◽  
First Results ◽  
Alpha Persei ◽  
Mass Functions ◽  
Tidal Tails ◽  
Gaia Dr2

AbstractGaia DR2 catalog provides a unique possibility to study the three-dimensional structure and the three-dimensional velocity field of the nearby open clusters. We can either select stars with a maximum membership probability and the most accurate values for the proper motions, parallaxes, and the radial velocities, or study these clusters statistically using overwhelmingly large areas of sky of tens by tens degrees. The second approach allows us to reveal the extensive outer parts of the clusters - a corona and the tidal tails and to study the luminosity and mass functions of these clusters. We present the first results of the investigation of several nearby open clusters, including Pleiades, Alpha Persei, Ruprecht 147.

scholarly journals NGC 3293 revisited by the Gaia-ESO Survey

2014 ◽  
Vol 9 (S307) ◽  
pp. 140-141
Author(s):  
Thierry Semaan ◽  
Thierry Morel ◽  
Eric Gosset ◽  
Juan Zorec ◽  
Yves Frémat ◽  
...  
Keyword(s):  
Massive Stars ◽  
Open Cluster ◽  
Second Step ◽  
Chemical Abundances ◽  
Hot Stars ◽  
Fundamental Parameters ◽  
Medium Resolution ◽  
Young Open Cluster ◽  
Extended View

AbstractIn the framework of the Gaia-ESO survey we have determined the fundamental parameters of a large number of B-type stars in the Galactic, young open cluster NGC 3293. The determination of the stellar parameters is based on medium-resolution spectra obtained with FLAMES/GIRAFFE at ESO-VLT. As a second step, we adopted the accurate parameters to determine the chemical abundances of these hot stars. We present a comparison of our results with those obtained by the 'VLT-FLAMES survey of massive stars' (Evans et al. 2005). Our study increases the number of objects analysed and provides an extended view of this cluster.

scholarly journals Triggered massive star formation in the open cluster NGC 1893

2003 ◽  
Vol 212 ◽  
pp. 562-563
Author(s):  
Amparo Marco ◽  
Ignacio Negueruela
Keyword(s):  
Star Formation ◽  
Emission Line ◽  
Massive Star ◽  
Main Sequence ◽  
Open Cluster ◽  
Star Forming ◽  
Young Open Cluster ◽  
H Ii Region ◽  
Pms Stars ◽  
Bright Emission

We have carried out a search for emission line pre-main sequence (PMS) stars in the area of the star-forming young open cluster NGC 1893 by means of slitless spectroscopy. We find 19 emission line stars with spectral types spanning the range from early B-type to G-type. All the PMS stars are confined to two small regions: the outer rim of the molecular cloud associated with the H ii region IC 410 and the vicinity of the bright emission cometary nebulae Sim 129 and Sim 130. The overall spatial distribution of PMS stars strongly suggests, that present day star formation in NGC 1893 is triggered by the O-type stars in the cluster.

scholarly journals Structure, kinematics, and ages of the young stellar populations in the Orion region

2019 ◽  
Vol 628 ◽  
pp. A123 ◽  
Author(s):  
E. Zari ◽  
A. G. A. Brown ◽  
P. T. de Zeeuw
Keyword(s):  
Star Formation ◽  
Clustering Algorithm ◽  
Age Distribution ◽  
Three Dimensional ◽  
Star Formation History ◽  
Dimensional Structure ◽  
Mean Velocity ◽  
Fitting Procedure ◽  
Sequence Of Events ◽  
Kinematic Modelling

We present a study of the three dimensional structure, kinematics, and age distribution of the Orion OB association, based on the second data release of the Gaia satellite (Gaia DR2). Our goal is to obtain a complete picture of the star formation history of the Orion complex and to relate our findings to theories of sequential and triggered star formation. We selected the Orion population with simple photometric criteria, and we constructed a three dimensional map in galactic Cartesian co-ordinates to study the physical arrangement of the stellar clusters in the Orion region. The map shows structures that extend for roughly 150 pc along the line of sight, divided in multiple sub-clusters. We separated different groups by using the density-based clustering algorithm DBSCAN. We studied the kinematic properties of all the groups found by DBSCAN first by inspecting their proper motion distribution, and then by applying a kinematic modelling code based on an iterative maximum likelihood approach, which we used to derive their mean velocity, velocity dispersion, and isotropic expansion. We derived ages and extinction values for all the groups by using an isochrone fitting procedure. We confirm the presence of an old population (∼15 Myr) towards the 25 Ori region, and we find that groups with ages of 12 − 15 Myr are present also towards the Belt region. We notice the presence of a population of ∼10 Myr also in front of the Orion A molecular cloud. Our findings suggest that star formation in Orion does not follow a simple sequential scenario, but instead consists of multiple events, which caused kinematic and physical sub-structure. To fully explain the detailed sequence of events, specific simulations and further radial velocity data are needed.

scholarly journals Updated parameters of 1743 open clusters based on Gaia DR2

2021 ◽  
Vol 504 (1) ◽  
pp. 356-371
Author(s):  
W S Dias ◽  
H Monteiro ◽  
A Moitinho ◽  
J R D Lépine ◽  
G Carraro ◽  
...  
Keyword(s):  
Maximum Likelihood ◽  
Open Cluster ◽  
Open Clusters ◽  
Individual Member ◽  
Homogeneous Sample ◽  
Membership Probability ◽  
Fundamental Parameters ◽  
The Mean ◽  
Gaia Dr2

ABSTRACT In this study, we follow up our recent paper (Monteiro et al. 2020) and present a homogeneous sample of fundamental parameters of open clusters in our Galaxy, entirely based on Gaia DR2 data. We used published membership probability of the stars derived from Gaia DR2 data and applied our isochrone fitting code, updated as in Monteiro et al. (2020), to GBP and GRPGaia DR2 data for member stars. In doing this, we take into account the nominal errors in the data and derive distance, age, and extinction of each cluster. This work therefore provides parameters for 1743 open clusters and, as a by-product, a list of likely not physical or dubious open clusters is provided as well for future investigations. Furthermore, it was possible to estimate the mean radial velocity of 831 clusters (198 of which are new and unpublished so far), using stellar radial velocities from Gaia DR2 catalogue. By comparing the open cluster distances obtained from isochrone fitting with those obtained from a maximum likelihood estimate of individual member parallaxes, we found a systematic offset of (−0.05 ± 0.04) mas.

scholarly journals White dwarf-open cluster associations based on Gaia DR2

2020 ◽  
Vol 645 ◽  
pp. A13
Author(s):  
M. Prišegen ◽  
M. Piecka ◽  
N. Faltová ◽  
M. Kajan ◽  
E. Paunzen
Keyword(s):  
Open Cluster ◽  
Open Clusters ◽  
Photometric Data ◽  
Mass Relation ◽  
Physical Processes ◽  
Satellite Mission ◽  
Cluster Membership ◽  
Fundamental Parameters ◽  
Data Release ◽  
Gaia Dr2

Context. Fundamental parameters and physical processes leading to the formation of white dwarfs (WDs) may be constrained and refined by discovering WDs in open clusters (OCs). Cluster membership can be utilized to establish the precise distances, luminosities, ages, and progenitor masses of such WDs. Aims. We compile a list of probable WDs that are OC members in order to facilitate WD studies that are impractical or difficult to conduct for Galactic field WDs. Methods. We use recent catalogs of WDs and OCs that are based on the second data release of the Gaia satellite mission (GDR2) to identify WDs that are OC members. This crossmatch is facilitated by the astrometric and photometric data contained in GDR2 and the derived catalogs. Assuming that most of the WD members are of the DA type, we estimate the WD masses, cooling ages, and progenitor masses. Results. We have detected several new likely WD members and reassessed the membership of the literature WDs that had been previously associated with the studied OCs. Several of the recovered WDs fall into the recently reported discontinuity in the initial-final mass relation (IFMR) around Mi ∼ 2.0 M⊙, which allows for tighter constrains on the IFMR in this regime.

scholarly journals Study of open cluster NGC 5617 in Gaia era

2019 ◽  
Vol 14 (S353) ◽  
pp. 22-23
Author(s):  
D. Bisht ◽  
Qingfeng Zhu
Keyword(s):  
Data Base ◽  
Proper Motion ◽  
Open Cluster ◽  
Open Clusters ◽  
Fundamental Parameters ◽  
Magnitude Diagram ◽  
Cluster Properties ◽  
Open Question ◽  
Gaia Dr2

AbstractIdentification of member stars in open clusters is still an open question. Thanks to Gaia DR2 data base, which improves our statistics regarding true members in clusters to understand cluster properties much better way. In this paper, we identify the cluster members using proper motion and colour magnitude diagram for NGC 5617. In addition to this, we have determined more precise fundamental parameters as well.

scholarly journals IC 4665 DANCe

2019 ◽  
Vol 631 ◽  
pp. A57 ◽  
Author(s):  
N. Miret-Roig ◽  
H. Bouy ◽  
J. Olivares ◽  
L. M. Sarro ◽  
M. Tamura ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Open Cluster ◽  
Mass Function ◽  
Contamination Rate ◽  
Magnitude Distribution ◽  
Star Forming ◽  
Fundamental Parameters ◽  
Star Forming Regions ◽  
Magnitude Range ◽  
Young Open Cluster

Context. The study of star formation is extremely challenging, due to the lack of complete and clean samples of young nearby clusters and star-forming regions. The recent Gaia DR2 catalogue complemented with the deep ground-based COSMIC DANCe catalogue offers a new database of unprecedented accuracy to revisit the membership of clusters and star-forming regions. The 30 Myr open cluster IC 4665 is one of the few well-known clusters of this age and it is an excellent target where evolutionary models can be tested and planetary formation studied. Aims. We provide a comprehensive membership analysis of IC 4665 and study the following properties: empirical isochrones, distance, magnitude distribution, present-day system mass function, and spatial distribution. Methods. We used the Gaia DR2 catalogue together with the DANCe catalogue to look for members via a probabilistic model of the distribution of the observable quantities in both the cluster and background populations. Results. We obtained a final list of 819 candidate members that cover a 12.4 magnitude range (7 <  J <  19.4). We find that 50% are new candidates, and we estimate a conservative contamination rate of 20%. This unique sample of members allows us to obtain a present-day system mass function in the range of 0.02–6 M⊙, which reveals a number of details not seen in previous studies. In addition, we find that a spherically symmetric spatial distribution is favoured by our final list of members for this young open cluster. Conclusions. Our membership analysis represents a significant increase in the quantity and quality (low contamination) with respect to previous studies. It offers an excellent opportunity to revisit other fundamental parameters such as age.

scholarly journals Cluster membership for the long-period Cepheid calibrator SV Vul

2020 ◽  
Vol 494 (2) ◽  
pp. 3028-3036 ◽  
Author(s):  
I Negueruela ◽  
R Dorda ◽  
A Marco
Keyword(s):  
Open Cluster ◽  
Hubble Constant ◽  
Cluster Membership ◽  
Long Period ◽  
Classical Cepheids ◽  
Good Accordance ◽  
Young Open Cluster ◽  
Red Supergiants ◽  
Stellar Properties ◽  
Gaia Dr2

ABSTRACT Classical Cepheids represent the first step of the distance scale ladder. Claims of tension between the locally calculated Hubble constant and the values deduced from Planck’s results have sparked new interest in these distance calibrators. Cluster membership provides an independent distance measurement, as well as astrophysical context for studies of their stellar properties. Here, we report the discovery of a young open cluster in the vicinity of SV Vul, one of the most luminous Cepheids known in the Milky Way. Gaia DR2 data show that SV Vul is a clear astrometric and photometric member of the new cluster, which we name Alicante 13. Although dispersed, Alicante 13 is moderately well populated, and contains three other luminous stars, one early-A bright giant and two low-luminosity red supergiants. The cluster is about 30 Ma old at a nominal distance of 2.5 kpc. With this age, SV Vul should have a mass around $10$ M⊙, in good accordance with its luminosity, close to the highest luminosity for Cepheids allowed by recent stellar models.

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