4U 1626-67 : A prograde spinning X-ray pulsar in A 2500 S binary system.
Abstract
The binary period of 4U 1626-67 was found from an analysis of its optical pulsations. A single lower frequency sideband of the 2.4% amplitude 7.68-s optical pulsations from this X-ray pulsar was detected on at least three different nights in Fourier transforms of high-speed photometry obtained with the CTIO 4 m telescope. The 0.42% sidelobe pulsations have a frequency which is 0.4011(2) mHz lower than the frequency of the direct pulsations near 130.26 mHz. The weaker sidelobe pulsations are interpreted as arising from X-ray to optical reprocessing on the companion star and are shifted to the lower frequency by the rotation frequency of the binary orbit because the X-ray pulsar spins in the same sense as the orbital motion (direct or prograde).
- Publication:
-
The Astrophysical Journal
- Pub Date:
- March 1981
- DOI:
- 10.1086/158772
- Bibcode:
- 1981ApJ...244.1001M
- Keywords:
-
- Binary Stars;
- Pulsars;
- Stellar Radiation;
- Stellar Spectrophotometry;
- X Ray Sources;
- Fourier Transformation;
- Heao 1;
- Orbital Elements;
- Power Spectra;
- Stellar Motions;
- Astronomy