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A Massive White Dwarf Companion to the Eccentric Binary Pulsar System PSR B2303+46

van Kerkwijk, M. H. and Kulkarni, S. R. (1999) A Massive White Dwarf Companion to the Eccentric Binary Pulsar System PSR B2303+46. Astrophysical Journal Letters, 516 (1). L25-L28. ISSN 2041-8205. doi:10.1086/311991.

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Pulsars in close, eccentric binary systems are usually assumed to have another neutron star as a companion. These double neutron star binaries have proven to be the best laboratories for experimental general relativity and are the most secure candidates for gravitational wave interferometers. We present deep B, V, and R images of the field containing the eccentric binary pulsar system PSR B2303+46. We find a faint, blue object [B = 26.60 ± 0.09; (B-R)_0 = -0.4 ± 0.2] coincident with the timing position. We suggest that this object is the optical counterpart to the PSR B2303+46 system. The counterpart is too bright to reflect emission from the pulsar or a neutron star companion. Most likely, the companion of PSR B2303+46 is not a neutron star but a massive white dwarf. We show that the observations are consistent with a hot white dwarf companion (T_(eff) 5×10^4 K) with cooling age equal the characteristic age of the pulsar (t_(cool) ≃ 30 Myr) and mass within the range set by timing observations and the Chandrasekhar mass (1.2 < M_C < 1.4 M_☉). Given the eccentric orbit, the white dwarf must have formed before the neutron star, from what was originally the more massive star in the binary. Due to mass transfer, the originally less massive star could become sufficiently massive to end its life in a supernova explosion and form the radio pulsar. We constrain the mass of the pulsar to be in the range 1.24 < M_(PSR) < 1.44 M_☉.

Item Type:Article
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URLURL TypeDescription DOIArticle
Kulkarni, S. R.0000-0001-5390-8563
Additional Information:© 1999 The American Astronomical Society. Received 1999 January 11; accepted 1999 February 22; published 1999 March 9. We are grateful to Dave Monet for providing us with preliminary astrometric results from USNO-A2.0. We acknowledge support by a fellowship of the Royal Netherlands Academy of Arts and Sciences (M. H. v. K.) and by grants from NASA and NSF (S. R. K.). The observations reported here were obtained at the W. M. Keck Observatory, which is operated by the California Association for Research in Astronomy, a scientific partnership among California Institute of Technology, the University of California, and the NASA. It was made possible by the generous financial support of the W. M. Keck Foundation.
Funding AgencyGrant Number
Royal Netherlands Academy of Arts and SciencesUNSPECIFIED
W. M. Keck FoundationUNSPECIFIED
Subject Keywords:binaries: close; pulsars: individual (PSR B2303+46); stars: evolution
Issue or Number:1
Record Number:CaltechAUTHORS:20131106-110948354
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Official Citation:A Massive White Dwarf Companion to the Eccentric Binary Pulsar System PSR B2303+46 M. H. van Kerkwijk and S. R. Kulkarni 1999 ApJ 516 L25
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:42271
Deposited By: Tony Diaz
Deposited On:06 Nov 2013 19:18
Last Modified:10 Nov 2021 16:20

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