A Complete, Multicolour Survey of Absolute Proper Motions in the Anticentre Direction at Intermediate Latitude: Kinematics of the Galaxy’S Stellar Populations

1994 ◽  
pp. 447-449
Author(s):  
D. K. Ojha ◽  
O. Bienaymé ◽  
A. C. Robin
Keyword(s):  
Stellar Populations ◽  
Proper Motions

Internal kinematics of multiple stellar populations in globular clusters

2019 ◽  
Vol 14 (S351) ◽  
pp. 324-328
Author(s):  
Mattia Libralato
Keyword(s):  
High Precision ◽  
Globular Clusters ◽  
Hubble Space Telescope ◽  
Stellar Populations ◽  
Stellar Systems ◽  
Proper Motions ◽  
Space Telescope ◽  
Formation And Evolution ◽  
Galactic Globular Clusters ◽  
Shed Light

AbstractSpectroscopy and photometry have revealed existence, complexity and properties of the multiple stellar populations (mPOPs) hosted in Galactic globular clusters. However, the conundrum of the formation and evolution of mPOPs is far from being completely exploited: the available pieces of information seem not enough to shed light on these topics. Astrometry, and in particular high-precision proper motions, can provide us the sought-after answers about how mPOPs formed and have evolved in these ancient stellar systems. In the following, I present a brief overview of the observational results on the internal kinematics of the mPOPs in some GCs thanks to Hubble Space Telescope high-precision proper motions.

scholarly journals Galactic Structure with GSC-II Material

1998 ◽  
Vol 179 ◽  
pp. 228-230
Author(s):  
A. Spagna ◽  
M.G. Lattanzi ◽  
G. Massone ◽  
B.J. McLean ◽  
B.M. Lasker
Keyword(s):  
Stellar Populations ◽  
Galactic Structure ◽  
Proper Motions ◽  
The Galaxy ◽  
Photographic Photometry

Faint surveys of accurate colors and proper motions are fundamental for studying the physical and kinematical properties of the stellar populations in the Galaxy. A program designed to address such issues has been initiated on selected fields utilizing prototype material from the GSC-II project (see McLean et al. in this volume, p. 431). Photographic photometry V, B–V, V–Rc, is derived down to V = 18.5 with a precision of about 0.1 mag, together with absolute proper motions to σμ ≃ 3 mas/yr.

scholarly journals A Complete, Multicolour Survey of Absolute Proper Motions in the Anticentre Direction at Intermediate Latitude: Kinematics of the Galaxy's Stellar Populations

1994 ◽  
Vol 161 ◽  
pp. 447-449
Author(s):  
D.K. Ojha ◽  
O. Bienaymé ◽  
A.C. Robin
Keyword(s):  
Stellar Populations ◽  
Proper Motions ◽  
The Galaxy ◽  
Ubv Photometry ◽  
Better Than

We present the observational results of UBV photometry and absolute proper motions in the anticentre direction at intermediate latitude (l = 167.5°, b = 47.4°) for an 8.6 square degree field. The sample is complete down to V = 17, and the accuracy of the proper motions is better than per century for stars brighter than V = 16. It is attempted here to make an investigation of the structure and kinematics of the Galaxy from absolute proper motions. Details of the present work can be found elsewhere (Ojha et al. 1993).

scholarly journals A spectroscopic survey of late-type giants in the Milky Way disk and local halo substructure

2007 ◽  
Vol 3 (S248) ◽  
pp. 506-507
Author(s):  
A. A. Sheffield ◽  
S. R. Majewski ◽  
A. M. Cheung ◽  
C. M. Hampton ◽  
J. D. Crane ◽  
...  
Keyword(s):  
High Velocity ◽  
Milky Way ◽  
Stellar Populations ◽  
Radial Velocities ◽  
Solar Neighborhood ◽  
Proper Motions ◽  
Late Type ◽  
Halo Stars ◽  
Medium Resolution ◽  
Galactic Stellar Populations

AbstractWe report the results of a survey of late-type giants aimed at understanding the nature of the disk and nearby halo Galactic stellar populations. We have obtained medium resolution (2–4 Å) spectra for 749 late K and early M giants at mid-latitudes selected from the 2MASS catalog with the FOBOS system at Fan Mountain Observatory. These spectra provide radial velocities (RVs) at the 5 km s−1 level, spectroscopic [Fe/H] good to σ[Fe/H] = 0.25 dex, and information on the relative abundances of Mg/Fe and Na/Fe in these stars. Proper motions from UCAC2 are used to search for local substructures, in particular the leading arm of the Sagittarius tidal streamer passing through the solar neighborhood. The combined proper motions and RVs yield full 6D stellar space motions. We have, by way of kinematics, relatively cleanly isolated the thick disk from the typically high velocity substructures that compose the nearby halo.We find evidence for substructure in the kinematics and metallicities of local halo stars.

scholarly journals Kinematics of multiple stellar populations in Globular Clusters with Gaia

2019 ◽  
Vol 14 (S351) ◽  
pp. 281-284
Author(s):  
G. Cordoni ◽  
A. P. Milone ◽  
A. Mastrobuono-Battisti ◽  
A. F. Marino ◽  
E. P. Lagioia ◽  
...  
Keyword(s):  
Globular Clusters ◽  
Velocity Dispersion ◽  
Stellar Populations ◽  
Field Of View ◽  
Large Field ◽  
Proper Motions ◽  
Physical Processes ◽  
Internal Dynamics ◽  
Data Release ◽  
First Time

AbstractThe internal dynamics of multiple stellar populations in Globular Clusters (GCs) provides unique constraints on the physical processes responsible for their formation. Specifically, the present-day kinematics of cluster stars, such as rotation and velocity dispersion, seems to be related to the initial configuration of the system. In recent work (Milone et al. 2018), we analyzed for the first time the kinematics of the different stellar populations in NGC 0104 (47 Tucanae) over a large field of view, exploiting the Gaia Data Release 2 proper motions combined with multi-band ground-based photometry. In this paper, based on the work by Cordoni et al. (2019), we extend this analysis to six GCs, namely NGC 0288, NGC 5904 (M 5), NGC 6121 (M 4), NGC 6752, NGC 6838 (M 71) and further explore NGC 0104. Among the analyzed clusters only NGC 0104 and NGC 5904 show significant rotation on the plane of the sky. Interestingly, multiple stellar populations in NGC 5904 exhibit different rotation curves.

scholarly journals The proper motion of sub-populations in ω Centauri

2020 ◽  
Vol 637 ◽  
pp. A46 ◽  
Author(s):  
N. Sanna ◽  
E. Pancino ◽  
A. Zocchi ◽  
F. R. Ferraro ◽  
P. B. Stetson
Keyword(s):  
Globular Cluster ◽  
Proper Motion ◽  
Stellar Populations ◽  
Small Region ◽  
Proper Motions ◽  
High Quality ◽  
Original Analysis ◽  
Data Release ◽  
Multi Band

The galactic globular cluster ω Centauri is the most massive of its kind, with a complex mix of multiple stellar populations and several kinematic and dynamical peculiarities. Different mean proper motions have been detected among the three main sub-populations, implying that the most metal-rich one is of accreted origin. This particular piece of evidence has been a matter of debate because the available data have either not been sufficiently precise or limited to a small region of the cluster to ultimately confirm or refute the result. Using astrometry from the second Gaia data release and recent high-quality, multi-band photometry, we are now in a position to resolve the controversy. We reproduced the original analysis using the Gaia data and found that the three populations have the same mean proper motion. Thus, there is no need to invoke an accreted origin for the most metal-rich sub-population.

scholarly journals The Stellar Kinematics in the Main Meridional Section of the Galaxy

1993 ◽  
Vol 156 ◽  
pp. 231-235
Author(s):  
N. V. Kharchenko
Keyword(s):  
Main Part ◽  
Chemical Properties ◽  
Stellar Populations ◽  
Galactic Rotation ◽  
Proper Motions ◽  
Stellar Kinematics ◽  
Meridional Section ◽  
The Galaxy ◽  
And Chemical Properties

In the framework of the programme of studying the meridional section of the Galaxy (MEGA) the catalogue of stellar data (about 26500 stars) had been compiled and investigated. The main part of the catalogue consist of the proper motions of stars with respect to the galaxies. The stellar kinematical characteristics in the direction of the galactic rotation, the parameters of velocity ellipsoid and the relation between kinematical, spatial and chemical properties of stellar populations have been determined.

scholarly journals When the tale comes true: multiple populations and wide binaries in the Orion Nebula Cluster

2019 ◽  
Vol 627 ◽  
pp. A57 ◽  
Author(s):  
Tereza Jerabkova ◽  
Giacomo Beccari ◽  
Henri M. J. Boffin ◽  
Monika G. Petr-Gotzens ◽  
Carlo F. Manara ◽  
...  
Keyword(s):  
Star Formation ◽  
Binary Stars ◽  
Stellar Populations ◽  
Age Difference ◽  
Orion Nebula ◽  
Proper Motions ◽  
Wide Binary ◽  
Ratio Distribution ◽  
Single Burst ◽  
The Individual

Context. Recently published high-quality OmegaCAM photometry of the 3 × 3 deg around the Orion Nebula Cluster (ONC) in r, and i filters revealed three well-separated pre-main sequences in the color-magnitude diagram (CMD). The objects belonging to the individual sequences are concentrated toward the center of the ONC. The authors concluded that there are two competitive scenarios: a population of unresolved binaries and triples with an exotic mass ratio distribution, or three stellar populations with different ages (≈1 Myr age differences). Aims. We use Gaia DR2 in combination with the photometric OmegaCAM catalog to test and confirm the presence of the putative three stellar populations. We also study multiple stellar systems in the ONC for the first time using Gaia DR2. Methods. We selected ONC members based on parallaxes and proper motions and take advantage from OmegaCAM photometry that performs better than Gaia DR2 photometry in crowded regions. We identify two clearly separated sequences with a third suggested by the data. We used Pisa stellar isochrones to estimate ages of the stellar populations with absolute magnitudes computed using Gaia parallaxes on a star by star basis. Results. (1) We confirm that the second and third sequence members are more centrally concentrated toward the center of the ONC. In addition we find an indication that the parallax and proper motion distributions are different among the members of the stellar sequences. The age difference among stellar populations is estimated to be 1−2 Myr. (2) We use Gaia proper motions and other measures to identify and remove as many unresolved multiple system candidates as possible. Nevertheless we are still able to recover two well-separated sequences with evidence for the third one, supporting the existence of the three stellar populations. (3) Due to having ONC members with negligible fore- or background contamination we were able to identify a substantial number of wide binary objects (separation between 1000 and 3000 au) and with relative proper motions of the binary components consistent with zero. This challenges previously inferred values that suggested no wide binary stars exist in the ONC. Our inferred wide-binary fraction is ≈5%. Conclusions. We confirm the three populations correspond to three separated episodes of star formation. Based on this result, we conclude that star formation is not happening in a single burst in this region. In addition we identify 5% of wide-binary stars in the ONC that were thought not to be present.

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