Proper motions of stars in the open cluster M 37.

1966 ◽  
Vol 71 ◽  
pp. 736 ◽  
Author(s):  
A. R. Upgren
Keyword(s):  
Open Cluster ◽  
Proper Motions

Relative proper motions in the region of the open cluster NGC 1664.

1973 ◽  
Vol 78 ◽  
pp. 53 ◽  
Author(s):  
S. J. Kerridge ◽  
R. M. Nelson ◽  
W. S. Mesrobian
Keyword(s):  
Open Cluster ◽  
Proper Motions

scholarly journals The dynamics of an extremely young cluster probed for the first time

2009 ◽  
Vol 5 (S266) ◽  
pp. 386-389
Author(s):  
Christine Ducourant ◽  
Sylvain Bontemps ◽  
Didier Despois ◽  
Philippe André ◽  
Ramachrisna Teixeira ◽  
...  
Keyword(s):  
Velocity Field ◽  
Proper Motion ◽  
Velocity Dispersion ◽  
Open Cluster ◽  
Extended Period ◽  
Early Evolution ◽  
Proper Motions ◽  
Crucial Importance ◽  
Cluster Systems ◽  
First Time

AbstractWe present a proper-motion program that we have developed at ESO to measure, for the first time, proper motions of members of the nearby (125 pc), very young (4 × 105 yr) infrared ρ Ophiuchi cluster. Repeated imaging over an extended period will allow us to measure the global proper motion of the cluster and its velocity dispersion and will provide access to the ~ 1 km s−1 velocities for objects as faint as K = 15.7 mag. Access to the velocity field of such an extremely young cluster is of crucial importance to investigate the origin and early evolution of open cluster systems.

scholarly journals The extended main-sequence turn-off of the Milky Way open cluster Collinder 347

2019 ◽  
Vol 490 (2) ◽  
pp. 2414-2420 ◽  
Author(s):  
Andrés E Piatti ◽  
Charles Bonatto
Keyword(s):  
Main Sequence ◽  
Milky Way ◽  
Open Cluster ◽  
Age Difference ◽  
Proper Motions ◽  
Gaussian Distributions ◽  
Young Object ◽  
Magnitude Diagram ◽  
Chemical Content ◽  
Gaia Dr2

ABSTRACT We made use of the Gaia DR2 archive to comprehensively study the Milky Way open cluster Collinder 347, known until now as a very young object of solar metal content. However, the G versus GBP − GRP colour–magnitude diagram (CMD) of bonafide probable cluster members, selected on the basis of individual stellar proper motions, their spatial distribution, and placement in the CMD, reveals the existence of a Hyades-like age open cluster (log(t /yr) = 8.8) of moderately metal-poor chemical content ([Fe/H]  = −0.4 dex), with a present-day mass of 3.3 × 103 M⊙. The cluster exhibits an extended main-sequence turn-off (eMSTO) of nearly 500 Myr, while that computed assuming Gaussian distributions from photometric errors, stellar binarity, rotation, and metallicity spread yields an eMSTO of ∼340 Myr. Such an age difference points to the existence within the cluster of stellar populations with different ages.

scholarly journals Stellar population of Sco OB2 revealed by Gaia DR2 data

2019 ◽  
Vol 623 ◽  
pp. A112 ◽  
Author(s):  
F. Damiani ◽  
L. Prisinzano ◽  
I. Pillitteri ◽  
G. Micela ◽  
S. Sciortino
Keyword(s):  
Stellar Population ◽  
Main Sequence ◽  
Open Cluster ◽  
Proper Motions ◽  
Lower Mass ◽  
Global Pattern ◽  
Field Star ◽  
Photometric Measurements ◽  
Stellar Masses ◽  
Gaia Dr2

Context. The Sco OB2 association is the nearest OB association, extending over approximately 2000 square degrees on the sky. Only its brightest and most massive members are already known (from HIPPARCOS) across its entire size, while studies of its lower mass population refer only to small portions of its extent. Aims. In this work we exploit the capabilities of Gaia DR2 measurements to search for Sco OB2 members across its entire size and down to the lowest stellar masses. Methods. We used both Gaia astrometric (proper motions and parallaxes) and photometric measurements (integrated photometry and colors) to select association members, using minimal assumptions derived mostly from the HIPPARCOS studies. Gaia resolves small details in both the kinematics of individual Sco OB2 subgroups and their distribution with distance from the Sun. We developed methods to explore the 3D kinematics of a stellar population covering large sky areas. Results. We find nearly 11 000 pre-main-sequence (PMS) members of Sco OB2 (with less than 3% field-star contamination), plus ∼3600 main-sequence (MS) candidate members with a larger (10–30%) field-star contamination. A higher confidence subsample of ∼9200 PMS (and ∼1340 MS) members is also selected (<1% contamination for the PMS), however this group is affected by larger (∼15%) incompleteness. We separately classify stars in compact and diffuse populations. Most members belong to one of several kinematically distinct diffuse populations, whose ensemble clearly outlines the shape of the entire association. Upper Sco is the densest region of Sco OB2. It is characterized by a complex spatial and kinematical structure and has no global pattern of motion. Other dense subclusters are found in Lower Centaurus-Crux and in Upper Centaurus-Lupus; the richest example of the latter, which has been recently identified, is coincident with the group near V1062 Sco. Most of the clustered stars appear to be younger than the diffuse PMS population, suggesting star formation in small groups that rapidly disperse and are diluted, reaching space densities lower than field stars while keeping memory of their original kinematics. We also find that the open cluster IC 2602 has a similar dynamics to Sco OB2, and its PMS members are currently evaporating and forming a diffuse (size ∼10°) halo around its double-peaked core.

scholarly journals Proper Motion Survey in the Pleiades

1995 ◽  
Vol 148 ◽  
pp. 228-231
Author(s):  
J. Souchay ◽  
E. Schilbach
Keyword(s):  
Proper Motion ◽  
Open Cluster ◽  
Photometric Data ◽  
Proper Motions ◽  
Total Field

AbstractAs a first step of our open cluster programme a catalogue of proper motions and photographic U, B, V, R magnitudes for stars up to 18 mag within a region centered near Alcyone is presented. The catalogue is based on MAMA measurements of plates taken with Tautenburg and OCA (CERGA) Schmidt telescopes. The photometric survey includes ca. 65000 stars and covers a total field of about 25 square degrees. Proper motions have been obtained for ca. 40000 stars within a central 17 square degree region of this field. For the majority of stars in the survey an accuracy of 0.08 mag and 2 mas/year has been estimated for photometric data and proper motions, respectively. The results of the determination of the Pleiades membership up to 18th magnitude is presented.

scholarly journals NGC 2587: a sparse open cluster projected onto a populous star field

2009 ◽  
Vol 5 (S266) ◽  
pp. 504-507
Author(s):  
Andrés E. Piatti ◽  
Juan J. Clariá ◽  
Andrea V. Ahumada
Keyword(s):  
Heliocentric Distance ◽  
Open Cluster ◽  
Interstellar Extinction ◽  
New Method ◽  
Proper Motions ◽  
Solar Metallicity ◽  
Cluster Values ◽  
Star Field

AbstractWe present CCD BVIKC photometry in the field of the open cluster NGC 2587. We developed a new method to clean statistically the colour–magnitude diagrams. NGC 2587 is found to be slightly younger than the Hyades and probably of solar metallicity. From 18 probable members with measured proper motions, we derived the following mean cluster values: μα = −4.3 ± 3.6 mas yr−1 and μδ = −2.5 ± 3.4 mas yr−1. Colour excesses, E(B − V) = 0.10 and E(V − I) = 0.15 mag, and a heliocentric distance of 3.7 ± 0.7 kpc are obtained. The interstellar extinction in the cluster direction is found to follow the normal reddening law.

Relative proper motions of stars in the region of the open cluster NGC 2281.

1959 ◽  
Vol 64 ◽  
pp. 170 ◽  
Author(s):  
S. Vasilevskis ◽  
A. G. A. Balz
Keyword(s):  
Open Cluster ◽  
Proper Motions

scholarly journals Hipparcos: An Example Of Astrophysical Uses Of Astrometric Data

1988 ◽  
Vol 133 ◽  
pp. 259-264
Author(s):  
A.E. Gómez ◽  
F. Crifo
Keyword(s):  
Spectral Type ◽  
Open Cluster ◽  
Proper Motions ◽  
Distribution Versus ◽  
Mean Error ◽  
Double Stars ◽  
Rr Lyrae ◽  
Scale Calibration ◽  
Stellar Masses ◽  
Astrometric Data

Hipparcos will measure positions, proper motions and parallaxes for about 110 000 stars brighter than B = 13, with an expected mean error of 2.10−3 arcsec in positions and parallaxes and 2.10−3 arcsec/year in proper motions. The contents of the first provisional catalogue with respect to astrophysical problems is described, and the star distribution versus spectral type, magnitude and distance is given. All types of stars are well represented (spectral types, various evolutionary stages, giants, white dwarfs, …). Precise parallaxes for 29 000 stars closer than 100 pc will provide a new base for luminosity calibration, and will allow accurate stellar masses to be determined from double stars with known orbits. Precise proper motions, in conjunction with the improved distances, will substantially improve our knowledge of galactic structure. All types of stars used for the cosmic distance scale calibration are well represented: Cepheids, RR Lyrae, supergiants, open cluster stars.

scholarly journals A catalogue of open cluster radii determined from Gaia proper motions

2020 ◽  
Vol 495 (3) ◽  
pp. 2882-2893 ◽  
Author(s):  
Néstor Sánchez ◽  
Emilio J Alfaro ◽  
Fátima López-Martínez
Keyword(s):  
Open Cluster ◽  
Good Alternative ◽  
Spatial Distributions ◽  
Proper Motions ◽  
Position Space ◽  
Cluster Radius ◽  
Characteristic Radius ◽  
Data Release ◽  
Using Data ◽  
The Relationship

ABSTRACT In this work, we improve a previously published method to calculate in a reliable way the radius of an open cluster (OC). The method is based on the behaviour of stars in the proper motion space as the sampling changes in the position space. Here, we describe the new version of the method and show its performance and robustness. Additionally, we apply it to a large number of OCs using data from Gaia second data release to generate a catalogue of 401 clusters with reliable radius estimations. The range of obtained apparent radii goes from Rc = 1.4 ± 0.1 arcmin (for the cluster FSR 1651) to Rc = 25.5 ± 3.5 arcmin (for NGC 2437). Cluster linear sizes follow very closely a lognormal distribution with a mean characteristic radius of Rc = 3.7 pc, and its high radius tail can be fitted by a power law as $N \propto R_c^{-3.11\pm 0.35}$. Additionally, we find that number of members, cluster radius, and age follow the relationship $N_c \propto R_c^{1.2\pm 0.1} \cdot T_c^{-1.9\pm 0.4}$ where the younger and more extensive the cluster, the more members it presents. The proposed method is not sensitive to low density or irregular spatial distributions of stars and, therefore, is a good alternative or complementary procedure to calculate OC radii not having previous information on star memberships.

scholarly journals A method for determining the radius of an open cluster from stellar proper motions

2018 ◽  
Vol 475 (3) ◽  
pp. 4122-4132 ◽  
Author(s):  
Néstor Sánchez ◽  
Emilio J Alfaro ◽  
Fátima López-Martínez
Keyword(s):  
Open Cluster ◽  
Proper Motions ◽  
Stellar Proper Motions
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