scholarly journals White Dwarfs in the Solar Neighborhood

2007 ◽  
Vol 119 (861) ◽  
pp. 1345-1347
Author(s):  
John P. Subasavage
Keyword(s):  
White Dwarfs ◽  
Solar Neighborhood

scholarly journals Contribution of White Dwarfs to Cluster Masses

1998 ◽  
Vol 11 (1) ◽  
pp. 430-432
Author(s):  
Ted Von Hippel
Keyword(s):  
Stellar Evolution ◽  
Mass Fraction ◽  
Globular Clusters ◽  
White Dwarfs ◽  
Literature Search ◽  
Galactic Disk ◽  
Dynamical Evolution ◽  
Open Clusters ◽  
Solar Neighborhood ◽  
Current Evidence

The study of cluster white dwarfs (WDs) has been invigorated recently bythe Hubble Space Telescope (HST). Recent WD studies have been motivated by the new and independent cluster distance (Renzini et al. 1996), age (von Hippel et al. 1995; Richer et al. 1997), and stellar evolution (Koester & Reimers 1996) information that cluster WDs can provide. An important byproduct of these studies has been an estimate of the WD mass contribution in open and globular clusters. The cluster WD mass fraction is of importance for understanding the dynamical state and history of star clusters. It also bears an important connection to the WD mass fractions of the Galactic disk and halo. Current evidence indicates that the open clusters (e.g. von Hippel et al. 1996; Reid this volume) have essentially the same luminosity function (LF) as the solar neighborhood population. The case for the halo is less clear, despite the number of very good globular cluster LFs down to nearly 0.1 solar masses (e.g. Cool et al. 1996; Piotto, this volume), as the field halo LF is poorly known. For most clusters dynamical evolution should cause evaporation of the lowest mass members, biasing clusters to have flatter present-day mass functions (PDMFs) than the disk and halo field populations. Dynamical evolution should also allow cluster WDs to escape, though not in the same numbers as the much lower mass main sequence stars. The detailed connection between cluster PDMFs and the field IMF awaits elucidation from observations and the new combined N-body and stellar evolution models (Tout, this volume). Nevertheless, the WD mass fraction of clusters already provides an estimate for the WD mass fraction of the disk and halo field populations. A literature search to collect cluster WDs and a simple interpretive model follow. This is a work in progress and the full details of the literature search and the model will be published elsewhere.

Observations of White Dwarfs in the Solar Neighborhood

2004 ◽  
Vol 127 (3) ◽  
pp. 1702-1711 ◽  
Author(s):  
Adela Kawka ◽  
Stphane Vennes ◽  
John R. Thorstensen
Keyword(s):  
White Dwarfs ◽  
Solar Neighborhood

scholarly journals The Luminosity Function of White Dwarfs in the Local Disk and Halo

1989 ◽  
Vol 114 ◽  
pp. 15-23 ◽  
Author(s):  
James Liebert ◽  
Conard C. Dahn ◽  
David G. Monet
Keyword(s):  
White Dwarfs ◽  
Luminosity Function ◽  
Solar Neighborhood ◽  
Star Formation History ◽  
Empirical Estimates ◽  
Formation History ◽  
History Of ◽  
Cool White Dwarfs ◽  
Local Disk

The luminosity function (LF) and total space density of white dwarfs in the solar neighborhood contain important information about the star formation history of the stellar population, and provide an independent method of measuring its age. The first empirical estimates of the LF for degenerate stars were those of Weidemann (1967), Kovetz and Shaviv (1976) and Sion and Liebert (1977). The follow-up investigations made possible by the huge Luyten Palomar proper motion surveys, however, added many more faint white dwarfs to the known sample. While the number of known cool white dwarfs grew to nearly one hundred, these did not include any that were much fainter intrinsically than the coolest degenerates found from the early Luyten, van Biesbroeck and Eggen-Greenstein lists.

A New Wide Pair of Cool White Dwarfs in the Solar Neighborhood

2002 ◽  
Vol 565 (1) ◽  
pp. 539-544 ◽  
Author(s):  
R.‐D. Scholz ◽  
G. P. Szokoly ◽  
M. Andersen ◽  
R. Ibata ◽  
M. J. Irwin
Keyword(s):  
White Dwarfs ◽  
Solar Neighborhood ◽  
Cool White Dwarfs

scholarly journals VISITORS FROM THE HALO: 11 Gyr OLD WHITE DWARFS IN THE SOLAR NEIGHBORHOOD

2010 ◽  
Vol 715 (1) ◽  
pp. L21-L25 ◽  
Author(s):  
Mukremin Kilic ◽  
Jeffrey A. Munn ◽  
Kurtis A. Williams ◽  
P. M. Kowalski ◽  
Ted von Hippel ◽  
...  
Keyword(s):  
White Dwarfs ◽  
Solar Neighborhood

scholarly journals Extended stellar systems in the solar neighborhood

2020 ◽  
Vol 639 ◽  
pp. A64 ◽  
Author(s):  
Sebastian Ratzenböck ◽  
Stefan Meingast ◽  
João Alves ◽  
Torsten Möller ◽  
Immanuel Bomze
Keyword(s):  
Support Vector Machines ◽  
White Dwarfs ◽  
Planet Formation ◽  
Dynamical Evolution ◽  
Solar Neighborhood ◽  
Support Vector ◽  
Stellar Systems ◽  
High Fidelity ◽  
Vector Machines ◽  
Formation And Evolution

Context. Nearby stellar streams carry unique information on the dynamical evolution and disruption of stellar systems in the Galaxy, the mass distribution in the disk, and they provide unique targets for planet formation and evolution studies. Recently, Meingast 1, a 120° stellar stream with a length of at least 400 pc, was dicovered. Aims. We aim to revisit the Meingast 1 stream to search for new members within its currently known 400 pc extent, using Gaia DR2 data and an innovative machine learning approach. Methods. We used a bagging classifier of one-class support vector machines with Gaia DR2 data to perform a 5D search (positions and proper motions) for new stream members. The ensemble was created by randomly sampling 2.4 million hyper-parameter realizations admitting classifiers that fulfill a set of prior assumptions. We used the variable prediction frequency resulting from the multitude of classifiers to estimate a stream membership criterion, which we used to select high-fidelity sources. We used the HR diagram and the Cartesian velocity distribution as test and validation tools. Results. We find about 2000 stream members with high fidelity, or about an order of magnitude more than previously known, unveiling the stream’s population across the entire stellar mass spectrum, from B stars to M stars, including white dwarfs. We find that, apart from being slightly more metal poor, the HRD of the stream is indistinguishable from that of the Pleiades cluster. For the mass range at which we are mostly complete, ∼0.2 M⊙ <  M <  ∼4 M⊙, we find a normal IMF, allowing us to estimate the total mass of stream to be about 2000 M⊙, making this relatively young stream by far the most massive one known. In addition, we identify several white dwarfs as potential stream members. Conclusions. The nearby Meingast 1 stream, due to its richness, age, and distance, is a new fundamental laboratory for star and planet formation and evolution studies for the poorly studied and gravitationally unbound star formation mode. We also demonstrate that one-class support vector machines can be effectively used to unveil the full stellar populations of nearby stellar systems with Gaia data.

scholarly journals The Future Is Now: The Formation of Single Low‐Mass White Dwarfs in the Solar Neighborhood

2007 ◽  
Vol 671 (1) ◽  
pp. 761-766 ◽  
Author(s):  
Mukremin Kilic ◽  
K. Z. Stanek ◽  
M. H. Pinsonneault
Keyword(s):  
White Dwarfs ◽  
Solar Neighborhood ◽  
The Future ◽  
Low Mass

scholarly journals SPITZEROBSERVATIONS OF THE OLDEST WHITE DWARFS IN THE SOLAR NEIGHBORHOOD

2009 ◽  
Vol 696 (2) ◽  
pp. 2094-2103 ◽  
Author(s):  
Mukremin Kilic ◽  
Piotr M. Kowalski ◽  
William T. Reach ◽  
Ted von Hippel
Keyword(s):  
White Dwarfs ◽  
Solar Neighborhood
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