Independent distance determinations to Milky Way Cepheids in open clusters and associations. 1: The binary Cepheid DL CAS in NGC 129

1994 ◽  
Vol 107 ◽  
pp. 2093 ◽  
Author(s):  
Wolfgang P. Gieren ◽  
Douglas L. Welch ◽  
Jean-Claude Mermilliod ◽  
Jaymie M. Matthews ◽  
Gisela Hertling
Keyword(s):  
Milky Way ◽  
Open Clusters ◽  
Open Clusters And Associations

scholarly journals Independent Distance Determinations to Milky Way Cepheids in Open Clusters: A progress report on four stars

1995 ◽  
Vol 155 ◽  
pp. 361-362
Author(s):  
Wolfgang P. Giere ◽  
Jaymie M. Matthews ◽  
Jean-Claude Mermilliod ◽  
Douglas Welch
Keyword(s):  
Surface Brightness ◽  
Milky Way ◽  
Zero Point ◽  
Progress Report ◽  
Open Clusters ◽  
Open Clusters And Associations ◽  
Preliminary Results

AbstractWe have undertaken a programme to calibrate the Cepheid PL relation zero-point by obtaining distances of Cepheids in open clusters and associations via the visual surface brightness technique. Results are now available for four stars (SZ Tau, CF Cas, CV Mon and DL Cas) and others are currently under analysis. Preliminary results suggest the ‘ZAMS-fitting’ distances to the host clusters are systematically smaller than those we derive from Cepheid surface brightnesses.

Independent Distance Determinations to Milky Way Cepheids in Open Clusters and Associations. III. CV MON in Anon Van Den Bergh

1996 ◽  
Vol 111 ◽  
pp. 2059 ◽  
Author(s):  
Wolfgang P. Gieren ◽  
Jean-Claude Mermilliod ◽  
Jaymie M. Mathews ◽  
Douglas L. Welch
Keyword(s):  
Milky Way ◽  
Open Clusters ◽  
Open Clusters And Associations

scholarly journals Reanalysis of nearby open clusters using Gaia DR1/TGAS and HSOY

2018 ◽  
Vol 615 ◽  
pp. A12 ◽  
Author(s):  
Steffi X. Yen ◽  
Sabine Reffert ◽  
Elena Schilbach ◽  
Siegfried Röser ◽  
Nina V. Kharchenko ◽  
...  
Keyword(s):  
Milky Way ◽  
Open Cluster ◽  
Star Clusters ◽  
Open Clusters ◽  
Parameter Estimates ◽  
Cluster Membership ◽  
Fitting Procedure ◽  
Cluster Data ◽  
The Galaxy ◽  
Automatic Tool

Context. Open clusters have long been used to gain insights into the structure, composition, and evolution of the Galaxy. With the large amount of stellar data available for many clusters in the Gaia era, new techniques must be developed for analyzing open clusters, as visual inspection of cluster color-magnitude diagrams is no longer feasible. An automatic tool will be required to analyze large samples of open clusters. Aims. We seek to develop an automatic isochrone-fitting procedure to consistently determine cluster membership and the fundamental cluster parameters. Methods. Our cluster characterization pipeline first determined cluster membership with precise astrometry, primarily from TGAS and HSOY. With initial cluster members established, isochrones were fitted, using a χ2 minimization, to the cluster photometry in order to determine cluster mean distances, ages, and reddening. Cluster membership was also refined based on the stellar photometry. We used multiband photometry, which includes ASCC-2.5 BV, 2MASS JHKs, and Gaia G band. Results. We present parameter estimates for all 24 clusters closer than 333 pc as determined by the Catalogue of Open Cluster Data and the Milky Way Star Clusters catalog. We find that our parameters are consistent to those in the Milky Way Star Clusters catalog. Conclusions. We demonstrate that it is feasible to develop an automated pipeline that determines cluster parameters and membership reliably. After additional modifications, our pipeline will be able to use Gaia DR2 as input, leading to better cluster memberships and more accurate cluster parameters for a much larger number of clusters.

scholarly journals Extended Main-sequence Turnoff as a Common Feature of Milky Way Open Clusters

2018 ◽  
Vol 869 (2) ◽  
pp. 139 ◽  
Author(s):  
G. Cordoni ◽  
A. P. Milone ◽  
A. F. Marino ◽  
M. Di Criscienzo ◽  
F. D’Antona ◽  
...  
Keyword(s):  
Main Sequence ◽  
Milky Way ◽  
Open Clusters

scholarly journals A Gaia DR2 view of the open cluster population in the Milky Way

2018 ◽  
Vol 618 ◽  
pp. A93 ◽  
Author(s):  
T. Cantat-Gaudin ◽  
C. Jordi ◽  
A. Vallenari ◽  
A. Bragaglia ◽  
L. Balaguer-Núñez ◽  
...  
Keyword(s):  
Stellar Evolution ◽  
Milky Way ◽  
Galactic Plane ◽  
Galactic Disk ◽  
Open Cluster ◽  
Open Clusters ◽  
Number Of Clusters ◽  
History Of ◽  
Gaia Dr2

Context. Open clusters are convenient probes of the structure and history of the Galactic disk. They are also fundamental to stellar evolution studies. The second Gaia data release contains precise astrometry at the submilliarcsecond level and homogeneous photometry at the mmag level, that can be used to characterise a large number of clusters over the entire sky. Aims. In this study we aim to establish a list of members and derive mean parameters, in particular distances, for as many clusters as possible, making use of Gaia data alone. Methods. We compiled a list of thousands of known or putative clusters from the literature. We then applied an unsupervised membership assignment code, UPMASK, to the Gaia DR2 data contained within the fields of those clusters. Results. We obtained a list of members and cluster parameters for 1229 clusters. As expected, the youngest clusters are seen to be tightly distributed near the Galactic plane and to trace the spiral arms of the Milky Way, while older objects are more uniformly distributed, deviate further from the plane, and tend to be located at larger Galactocentric distances. Thanks to the quality of Gaia DR2 astrometry, the fully homogeneous parameters derived in this study are the most precise to date. Furthermore, we report on the serendipitous discovery of 60 new open clusters in the fields analysed during this study.

scholarly journals The evolution of the Milky Way: new insights from open clusters

2016 ◽  
Vol 463 (4) ◽  
pp. 4366-4382 ◽  
Author(s):  
Arumalla B. S. Reddy ◽  
David L. Lambert ◽  
Sunetra Giridhar
Keyword(s):  
Milky Way ◽  
Open Clusters

scholarly journals The Gaia-ESO Survey: membership probabilities for stars in 32 open clusters from 3D kinematics

2020 ◽  
Vol 496 (4) ◽  
pp. 4701-4716 ◽  
Author(s):  
R J Jackson ◽  
R D Jeffries ◽  
N J Wright ◽  
S Randich ◽  
G Sacco ◽  
...  
Keyword(s):  
Maximum Likelihood ◽  
Proper Motion ◽  
Milky Way ◽  
Open Clusters ◽  
Evolutionary Models ◽  
Valuable Resource ◽  
3D Kinematics ◽  
Cluster Membership ◽  
Data Release ◽  
Average Probability

ABSTRACT The Gaia-ESO Survey (GES) observed many open clusters as part of its programme to spectroscopically characterize the various Milky Way populations. GES spectroscopy and Gaia astrometry from its second data release are used here to assign membership probabilities to targets towards 32 open clusters with ages from 1 to 3800 Myr, based on maximum likelihood modelling of the 3D kinematics of the cluster and field populations. From a parent catalogue of 14 398 individual targets, 5032 stars with uniformly determined 3D velocities, Teff, log g, and chemistry are assigned cluster membership with probability >0.9, and with an average probability of 0.991. The robustness of the membership probabilities is demonstrated using independent membership criteria (lithium and parallax) in two of the youngest clusters. The addition of radial velocities improves membership discrimination over proper motion selection alone, especially in more distant clusters. The kinematically selected nature of the membership lists, independent of photometry and chemistry, makes the catalogue a valuable resource for testing stellar evolutionary models and investigating the time evolution of various parameters.

scholarly journals An Overview of the Globular Cluster System of the Galaxy

1988 ◽  
Vol 126 ◽  
pp. 37-48
Author(s):  
Robert Zinn
Keyword(s):  
Globular Cluster ◽  
Globular Clusters ◽  
Milky Way ◽  
Galactic Center ◽  
Galactic Plane ◽  
Cluster System ◽  
Open Clusters ◽  
The Galaxy ◽  
Globular Cluster System ◽  
Harlow Shapley

Harlow Shapley (1918) used the positions of globular clusters in space to determine the dimensions of our Galaxy. His conclusion that the Sun does not lie near the center of the Galaxy is widely recognized as one of the most important astronomical discoveries of this century. Nearly as important, but much less publicized, was his realization that, unlike stars, open clusters, HII regions and planetary nebulae, globular clusters are not concentrated near the plane of the Milky Way. His data showed that the globular clusters are distributed over very large distances from the galactic plane and the galactic center. Ever since this discovery that the Galaxy has a vast halo containing globular clusters, it has been clear that these clusters are key objects for probing the evolution of the Galaxy. Later work, which showed that globular clusters are very old and, on average, very metal poor, underscored their importance. In the spirit of this research, which started with Shapley's, this review discusses the characteristics of the globular cluster system that have the most bearing on the evolution of the Galaxy.

scholarly journals A PSF-based Approach to TESS High quality data Of Stellar clusters (PATHOS) – III. Exploring the properties of young associations through their variables, dippers, and candidate exoplanets

2020 ◽  
Vol 498 (4) ◽  
pp. 5972-5989
Author(s):  
D Nardiello
Keyword(s):  
Variable Stars ◽  
Open Clusters ◽  
Light Curves ◽  
Quality Data ◽  
Stellar Systems ◽  
Satellite Mission ◽  
Open Clusters And Associations ◽  
Star Forming ◽  
Star Forming Regions ◽  
Strong Candidate

ABSTRACT Young associations in star-forming regions are stellar systems that allow us to understand the mechanisms that characterize the stars in their early life and what happens around them. In particular, the analysis of the discs and of the exoplanets around young stars allows us to know the key processes that prevail in their evolution and understand the properties of the exoplanets orbiting older stars. The Transiting Exoplanet Survey Satellite mission is giving us the opportunity to extract and analyse the light curves of association members with high accuracy, but the crowding that affects these regions makes difficult the light curve extraction. In the PATHOS project, cutting-edge tools are used to extract high-precision light curves and identify variable stars and transiting exoplanets in open clusters and associations. In this work, I analysed the light curves of stars in five young (≲10 Myr) associations, searching for variables and candidate exoplanets. Using the rotational periods of the association members, I constrained the ages of the five stellar systems (∼2–10 Myr). I searched for dippers, and I investigated the properties of the dust that forms the circumstellar discs. Finally, I searched for transiting signals, finding six strong candidate exoplanets. No candidates with radius RP ≲ 0.9 RJ have been detected, in agreement with the expectations. The frequency of giant planets resulted to be ∼2–3 per cent, higher than that expected for field stars (≲ 1 per cent); the low statistic makes this conclusion not strong, and new investigations on young objects are mandatory to confirm this result.

Sign in / Sign up

Export Citation Format

Share Document