Massive White Dwarfs in Young Star Clusters
Abstract
We have carried out a search for massive white dwarfs (WDs) in the direction of young open star clusters using the Gaia DR2 database. The aim of this survey was (1) to provide robust data for new and previously known high-mass WDs regarding cluster membership, (2) to highlight WDs previously included in the initial final mass relation (IFMR) that are unlikely members of their respective clusters according to Gaia astrometry, and (3) to select an unequivocal WD sample that could then be compared with the host clusters' turnoff masses. All promising WD candidates in each cluster color–magnitude diagram were followed up with spectroscopy from Gemini in order to determine whether they were indeed WDs and derive their masses, temperatures, and ages. In order to be considered cluster members, white dwarfs were required to (1) have proper motions and parallaxes within 2σ, 3σ, or 4σ of those of their potential parent cluster based on how contaminated the field was in their region of the sky, (2) have a cooling age that was less than the cluster age, and (3) have a mass that was broadly consistent with the IFMR. A number of WDs included in current versions of the IFMR turned out to be nonmembers, and a number of apparent members, based on Gaia's astrometric data alone, were rejected, as their mass and/or cooling times were incompatible with cluster membership. In this way, we developed a highly selected IFMR sample for high-mass WDs that, surprisingly, contained no precursor masses significantly in excess of ~ 6 M_⊙.
Additional Information
© 2021. The American Astronomical Society. Received 2020 December 5; revised 2021 January 12; accepted 2021 January 15; published 2021 May 17. The research was supported by NSERC Canada, Compute Canada, and a Burke Fellowship at Caltech. Spectra were obtained at the international Gemini Observatory. We used the Montreal White Dwarf website (http://www.astro.umontreal.ca/bergeron/CoolingModels), the PARSEC stellar models (http://stev.oapd.inaf.it/cgi-bin/cmd), the MIST stellar models (http://waps.cfa.harvard.edu/MIST) and the VizieR catalog access tool, CDS, Strasbourg, France (doi:10.26093/cds/vizier). This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. Facilities: Gaia(DR2) - , Gemini North and South. - Software: Astropy (Astropy Collaboration et al. 2013, 2018), Cloudy (Ferland et al. 2013), SExtractor (Bertin & Arnouts 1996).Attached Files
Published - Richer_2021_ApJ_912_165.pdf
Accepted Version - 2101.08300.pdf
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Additional details
- Eprint ID
- 109483
- Resolver ID
- CaltechAUTHORS:20210611-102236029
- Natural Sciences and Engineering Research Council of Canada (NSERC)
- Compute Canada
- Sherman Fairchild Foundation
- Gaia Multilateral Agreement
- Created
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2021-06-11Created from EPrint's datestamp field
- Updated
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2021-06-11Created from EPrint's last_modified field
- Caltech groups
- TAPIR