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A 1.05 M_☉ Companion to PSR J2222–0137: The Coolest Known White Dwarf?

Kaplan, David L. and Boyles, Jason and Dunlap, Bart H. and Tendulkar, Shriharsh P. and Deller, Adam T. and Ransom, Scott M. and McLaughlin, Maura A. and Lorimer, Duncan R. and Stairs, Ingrid H. (2014) A 1.05 M_☉ Companion to PSR J2222–0137: The Coolest Known White Dwarf? Astrophysical Journal, 789 (2). Art. No. 119. ISSN 0004-637X. doi:10.1088/0004-637X/789/2/119.

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The recycled pulsar PSR J2222–0137 is one of the closest known neutron stars (NSs) with a parallax distance of 267_(-0.9)^(+1.2) pc and an edge-on orbit. We measure the Shapiro delay in the system through pulsar timing with the Green Bank Telescope, deriving a low pulsar mass (1.20 ± 0.14 M_☉) and a high companion mass (1.05 ± 0.06 M_☉) consistent with either a low-mass NS or a high-mass white dwarf. We can largely reject the NS hypothesis on the basis of the system's extremely low eccentricity (3 × 10^(–4))—too low to have been the product of two supernovae under normal circumstances. However, despite deep optical and near-infrared searches with Southern Astrophysical Research and the Keck telescopes we have not discovered the optical counterpart of the system. This is consistent with the white dwarf hypothesis only if the effective temperature is <3000 K, a limit that is robust to distance, mass, and atmosphere uncertainties. This would make the companion to PSR J2222–0137 one of the coolest white dwarfs ever observed. For the implied age to be consistent with the age of the Milky Way requires the white dwarf to have already crystallized and entered the faster Debye-cooling regime.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Kaplan, David L.0000-0001-6295-2881
Tendulkar, Shriharsh P.0000-0003-2548-2926
Deller, Adam T.0000-0001-9434-3837
Alternate Title:A 1.05 M☉ Companion to PSR J2222–0137: The Coolest Known White Dwarf?
Additional Information:© 2014 American Astronomical Society. Received 2014 April 4; accepted 2014 May 20; published 2014 June 20. We thank an anonymous referee for useful suggestions, and T. Tauris, M. van Kerkwijk, P. Bergeron, and R. O’Shaughnessy for helpful discussions. D.L.K. is supported by the National Science Foundation grant AST-1312822. M.A.M. and D.R.L. are supported by WVEPSCOR, the NSF PIRE Program, and the Research Corporation for Scientific Advancement. JRB acknowledges support from WVEPSCoR, the National Radio Astronomy Observatory, the National Science Foundation (AST 0907967), and the Smithsonian Astrophysical Observatory (Chandra Proposal 12400736). A.T.D. was supported by an NWO Veni Fellowship. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. Based on observations obtained at the Southern Astrophysical Research (SOAR) telescope, which is a joint project of the Ministério da Ciência, Tecnologia, e Inovação (MCTI) da República Federativa do Brasil, the U.S. National Optical Astronomy Observatory (NOAO), the University of North Carolina at Chapel Hill (UNC), and Michigan State University (MSU). Funding for SDSS-III has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, and the U.S. Department of Energy Office of Science. The SDSS-IIIWeb site is made extensive use of SIMBAD, ADS, and Astropy (; Astropy Collaboration et al. 2013). Pulsar research at UBC is supported by an NSERC Discovery grant. Facilities: GBT, Keck:I (LRIS), Keck:II (NIRC2)
Funding AgencyGrant Number
Research CorporationUNSPECIFIED
National Radio Astronomy ObservatoryUNSPECIFIED
NSFAST 0907967
Smithsonian Astrophysical Observatory12400736
Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO)UNSPECIFIED
W. M. Keck FoundationUNSPECIFIED
Alfred P. Sloan FoundationUNSPECIFIED
Participating InstitutionsUNSPECIFIED
Department of Energy (DOE)UNSPECIFIED
Natural Sciences and Engineering Research Council of Canada (NSERC)UNSPECIFIED
Subject Keywords:binaries: general; pulsars: individual (PSR J2222-0137); stars: distances; stars: fundamental parameters
Issue or Number:2
Record Number:CaltechAUTHORS:20140807-125908951
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Official Citation:A 1.05 M ☉ Companion to PSR J2222–0137: The Coolest Known White Dwarf? David L. Kaplan et al. 2014 ApJ 789 119
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:48183
Deposited By: Ruth Sustaita
Deposited On:07 Aug 2014 21:13
Last Modified:10 Nov 2021 18:05

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