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Discovery of the Orbit of the X-Ray Pulsar OAO 1657-415

Chakrabarty, Deepto and Grunsfeld, John M. and Prince, Thomas A. and Bildsten, Lars and Finger, Mark H. and Wilson, Robert B. and Fishman, Gerald J. and Meegan, Charles A. and Paciesas, William S. (1993) Discovery of the Orbit of the X-Ray Pulsar OAO 1657-415. Astrophysical Journal, 403 . L33-L37. ISSN 0004-637X. doi:10.1086/186715.

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Timing observations of the 38 s accreting X-ray pulsar OAO 1657-415 made with the BATSE large-area detectors on the Compton Gamma Ray Observatory have revealed a binary orbit with an X-ray eclipse by the stellar companion. Arrival time analysis of 20-60 keV data yielded the following best-fit orbital elements: P_(orb) = 10^d.4436 ± 0^d.0038, a_x sin i = 106.0 ± 0.5 lt-sec, e = 0.104 ± 0.005, ω = 93° ± 5°, T_(π/2) = JD 2,448,516.49 ± 0.05 TDB. From the pulsar mass function f_x(M) = 11.7 ± 0.2 M_⊙ and the measured eclipse half-angle θ_e = 29.7 ± 1.3 deg, we infer that the stellar companion is a supergiant of spectral class B0-B6. If the companion can be identified and its orbital velocity measured, the neutron star mass can be constrained. Both intrinsic spin-up and spin-down of the pulsar were measured during our observation.

Item Type:Article
Related URLs:
URLURL TypeDescription
Chakrabarty, Deepto0000-0001-8804-8946
Prince, Thomas A.0000-0002-8850-3627
Additional Information:Copyright 1993, American Astronomical Society. Received 1992 September 28; accepted 1992 November 5. We would like to acknowledge the significant contributions to this work made by the entire BATSE team at NASA/Marshall Space Flight Center, and useful discussions with Stuart Anderson and Paul Ray at Caltech. An anonymous referee made several helpful suggestions. This work was funded in part by NASA grants NAGW-1919, NAGW-2920, and NAG 5-1458, and a Lee A. DuBridge fellowship to L. B. funded by the Weingart Foundation.
Group:Space Radiation Laboratory
Funding AgencyGrant Number
NASANAG 5-1458
Lee A. DuBridge FellowshipUNSPECIFIED
Weingart FoundationUNSPECIFIED
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Other Numbering System NameOther Numbering System ID
Space Radiation Laboratory1992-07
Record Number:CaltechAUTHORS:20140512-104727413
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:45677
Deposited By: Deborah Miles
Deposited On:12 May 2014 22:11
Last Modified:10 Nov 2021 17:15

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