scholarly journals Ensemble evolutionary studies of white dwarfs in open star clusters

2019 ◽  
Vol 15 (S357) ◽  
pp. 179-183
Author(s):  
Kurtis A Williams
Keyword(s):  
White Dwarfs ◽  
Binary Star ◽  
Open Cluster ◽  
Star Clusters ◽  
Mass Relation ◽  
Correlated Errors ◽  
Open Star Clusters ◽  
Open Star ◽  
Final Mass ◽  
Evolutionary Studies

AbstractWhite dwarfs (WDs) in open star clusters are a highly useful ensemble of stars. While numerous researchers use open cluster WDs to study the initial-final mass relation, numerous other evolutionary studies are also enabled by this sample of stars, including searches for stochastic mass loss, studies of binary star evolution, and measurements of metallicity impacts on WD formation and evolution. However, it is crucial to use astrometric data such as proper motions to remove contaminating field WDs from open cluster samples; multi-epoch ground based imaging is needed for most open cluster WDs. Also, the strongly correlated errors in the initial mass - final mass plane must be considered; we illustrate the importance of this consideration using a large open cluster WD sample and Monte Carlo techniques.

Double degenerate candidates in the open cluster NGC 6633

2019 ◽  
Vol 15 (S357) ◽  
pp. 20-23
Author(s):  
Joseph W. Barnett ◽  
Kurtis A. Williams
Keyword(s):  
White Dwarfs ◽  
Binary Star ◽  
Open Cluster ◽  
Star Clusters ◽  
Sequence Evolution ◽  
Total System ◽  
Open Star Clusters ◽  
Low Mass Stars ◽  
Cluster Membership ◽  
Open Star

AbstractThe study of white dwarfs, the end stage of stellar evolution for more than 95% of stars, is critical to bettering our understanding of the late stages of the lives of low mass stars. In particular, the post main sequence evolution of binary star systems is complex, and the identification and analysis of double degenerate systems is a crucial step in constraining models of binary star systems. Binary white dwarfs in open star clusters are particularly useful because cluster parameters such as distance, metal content, and total system age are more tightly constrained than for field double degenerates. Here we use the precision astrometry from the Gaia Data Release 2 catalog to study two other white dwarfs which were identified as candidate double degenerates in the field of the open star cluster NGC 6633. One of the two objects, LAWDS 4, is found to have astrometric properties fully consistent with that of the cluster. In such a case, the object is significantly overluminous for a single white dwarf, strongly indicating binarity. The second candidate binary, LAWDS 7, appears to be inconsistent with cluster membership, though a more thorough analysis is necessary to properly quantify the probability. At present we are proceeding to model the photometric and spectroscopic data for both objects as if they were cluster member double degenerates. Results of this latter analysis are forthcoming. Our results will add crucial data to the study of binary star evolution in open star clusters.

scholarly journals Study of possible regularities of the metallic distribution of open cluster stars according to the LAMOST catalog

2021 ◽  
Author(s):  
T. A. Permyakova ◽  
◽  
A. V. Loktin ◽  
Keyword(s):  
Open Cluster ◽  
Star Clusters ◽  
Absolute Magnitude ◽  
Systematic Errors ◽  
Stellar Magnitude ◽  
Open Star Clusters ◽  
Open Star ◽  
Statistical Studies ◽  
The Absolute

In this study were discussed the LAMOST catalog opportunities in the statistical studies of the spectra of stars in open star clusters (OSC). We considered the Pleiades and Praesepe clusters. We examined the absolute stellar magnitude — metallicity relationships for the members of these clusters. Contrary to expectations, a noticeable dependence of the metallicity on the absolute magnitude of the stars in the main sequences of the studied clusters was found, which may be associated with systematic errors in measuring the metallicities for visually faint stars.

scholarly journals Constraints on stellar evolution by observation of white dwarfs

1984 ◽  
Vol 105 ◽  
pp. 229-230 ◽  
Author(s):  
V. Weidemann
Keyword(s):  
White Dwarfs ◽  
Recent Observation ◽  
Open Cluster ◽  
High Mass ◽  
Mass Relation ◽  
List Type ◽  
Intermediate Mass Stars ◽  
Final Mass ◽  
Star Production ◽  
The Rich

The recent observation of white dwarfs in the open cluster NGC 2516 and the determination of their surface gravity and effective temperatures (Reimers and Koester, 1982) has enabled the establishment of the initial-final mass relation for low and intermediate mass stars which was published a few months ago and is presented here (Fig. 1 of Weidemann and Koester, 1983a). The most important conclusions drawn are: 1.The limiting mass for white dwarf progenitors is 8–9 M⊙ rather than 5–6 M⊙, with supernova production beyond;2.The rather flat run of the initial-final mass relation in the main range of star production, 1–5 M⊙, explains the observed narrow mass distribution of white dwarfs and central stars of planetary nebulae around 0.6 M⊙;3.High mass white dwarfs exist, as shown in the rich, young cluster NGC 2516, but are extremely rare in general.

scholarly journals The Dearth of Massive, Helium-rich White Dwarfs in Young Open Star Clusters

2004 ◽  
Vol 618 (2) ◽  
pp. L129-L132 ◽  
Author(s):  
Jasonjot Singh Kalirai ◽  
Harvey B. Richer ◽  
Brad M. S. Hansen ◽  
David Reitzel ◽  
R. Michael Rich
Keyword(s):  
White Dwarfs ◽  
Star Clusters ◽  
Open Star Clusters ◽  
Open Star

scholarly journals Massive open star clusters using the VVV survey

2012 ◽  
Vol 545 ◽  
pp. A54 ◽  
Author(s):  
A.-N. Chené ◽  
J. Borissova ◽  
J. R. A. Clarke ◽  
C. Bonatto ◽  
D. J. Majaess ◽  
...  
Keyword(s):  
Star Clusters ◽  
Open Star Clusters ◽  
Open Star

Photometric study of open star clusters in II quadrant: Teutsch 1 and Riddle 4

New Astronomy ◽  
2016 ◽  
Vol 42 ◽  
pp. 66-77 ◽  
Author(s):  
D. Bisht ◽  
R.K.S. Yadav ◽  
A.K. Durgapal
Keyword(s):  
Star Clusters ◽  
Photometric Study ◽  
Open Star Clusters ◽  
Open Star

scholarly journals A study of spatial structure of galactic open star clusters

2002 ◽  
Vol 383 (1) ◽  
pp. 153-162 ◽  
Author(s):  
Nilakshi ◽  
R. Sagar ◽  
A. K. Pandey ◽  
V. Mohan
Keyword(s):  
Spatial Structure ◽  
Star Clusters ◽  
Open Star Clusters ◽  
Open Star

scholarly journals Orbits of Open Star Clusters NGC 6067, NGC 2506 ANG IC 465

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Geeta Rangwal ◽  
R. K. S. Yadav ◽  
Alok K. Durgapal
Keyword(s):  
Proper Motion ◽  
Star Clusters ◽  
Open Star Clusters ◽  
Motion Data ◽  
Open Star ◽  
Galactic Clusters

The studies of the orbits of star clusters are very important to understand the evolution of these objects. The survival or dissolution of star clusters in galactic tides within which they orbit depends on their orbit history. The orbits of three galactic clusters namely NGC 6067, NGC 2506 and IC 4651 are calculated using newly available proper motion data taken from GAIA data. These orbits are traced backwards in time which is equal to the age of the clusters. The main parameters of the orbits such as eccentricity, apogalactic distance and perigalactic distance are calculated.

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