Optical observations of the eclipsing binary radio pulsar PSR1957 + 20
| Autor: | A. P. Smale, G. Machin, B. J. M. Hassall, P. A. Charles, Paul J. Callanan, Keith O. Mason, J. van Paradijs, J. Allington-Smith, Tim Naylor |
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| Rok vydání: | 1988 |
| Předmět: |
Physics
Brightness Multidisciplinary Astrophysics::High Energy Astrophysical Phenomena Astronomy White dwarf Astrophysics::Cosmology and Extragalactic Astrophysics Astrophysics Light curve Pulsar Millisecond pulsar Binary star Astrophysics::Solar and Stellar Astrophysics H-alpha Roche lobe Astrophysics::Earth and Planetary Astrophysics Astrophysics::Galaxy Astrophysics |
| Zdroj: | Nature. 334:684-686 |
| ISSN: | 1476-4687 0028-0836 |
| DOI: | 10.1038/334684a0 |
| Popis: | The recently discovered1 1.6 ms binary radio pulsar PSR1957 + 20 shows radio eclipses whose duration indicates that the occulting body is substantially larger than the Roche lobe of the low-mass (∼10–2M⊙) companion star. This suggests1–4 that this companion is evaporating through the action of a strong pulsar energy flux5. An optical counterpart has been detected which shows brightness variations in phase with the 9.2 h orbital cycle6. We have obtained optical charge coupled device (CCD) images which show that the counterpart is one component of a close visual pair separated by ∼0.7 arcsec. At maximum both are equally bright with combined V magnitude of 19.9, while at minimum PSR1957 + 20 is invisible. From spectroscopic observations we find that the contaminating star is a normal G star. The spectrum of PSR1957 + 20 shows intermittent Hα emission. We confirm that the optical brightness of PSR1957 + 20 varies in phase with the radio Doppler velocity curve1, and find that the amplitude is probably more than 3 magnitudes, minimum light coinciding with the radio eclipse. The optical light curve is consistent with heating of a hydrogen-rich low-mass white dwarf by high-energy radiation from the nearby millisecond pulsar. |
| Databáze: | OpenAIRE |
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