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Steady Energy Source in Her X-l?

Nature Physical Science volume 246, pages 36–37 (1973)Cite this article

Abstract

OBSERVATIONS of the Her X-l system show that the X-ray emission above ˜ 2 keV has three cycles : a pulsation period of 1.2 s; a 1.7-d orbital period associated with the motion of Her X-l about HZ Her; and a 35-d cycle during which the source is in a high, observable state for some 12 d, followed by a 23-d low period during which no X rays are observed1,2. Optical emission from HZ Her shows periodic brightness changes with a 1.7-d period, such that the phase of maximum brightness coincides with the maximum in the pulsed X-ray intensity3,4. These observations have been interpreted in terms of HZ Her as a late A or early F star which has a bright side as a result of heating due to radiation from Her X-l (refs 3 to 7).

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References

  1. Tananbaum, H., Gursky, H., Kellogg, E., Levinson, R., Schreier, E., and Giacconi, R., Astrophys. J. Lett., 174, L143 (1972).

    Article  ADS  Google Scholar 

  2. Giacconi, R., Murray, S., Gursky, H., Kellogg, E., Schreier, E., and Tananbaum, H., Astrophys. J., 178, 281 (1972).

    Article  ADS  Google Scholar 

  3. Bahcall, J. N., and Bahcall, N. A., Astrophys. J. Lett., 178, L1 (1972).

    Article  ADS  Google Scholar 

  4. Forman, W., Jones, C. A., and Liller, W., Astrophys. J. Lett., 177, L103 (1972).

    Article  ADS  Google Scholar 

  5. Davidsen, A., Henry, J. P., Middleditch, J., and Smith, H. E., Astrophys. J. Lett., 177, L97 (1972).

    Article  ADS  Google Scholar 

  6. Crampton, D., and Hutchings, J. B., Astrophys. J. Lett., 178, L65 (1972).

    Article  ADS  Google Scholar 

  7. Lyutiy, V. M., Sunyaev, R. A., and Cherepashchuk, A. M., Astron. Zhu., 50, 3 (1973). Sov. Astro. AJ, 17, 1 (1973).

    ADS  Google Scholar 

  8. Pringle, J., Nature phys. Sci., 243, 90 (1973).

    Article  ADS  Google Scholar 

  9. Petro, L., and Hiltner, W. A., Astrophys. J. Lett., 181, L39 (1973).

    Article  ADS  Google Scholar 

  10. Boynton, P. E., Canterna, R., Crosa, L., Deeter, J., and Gerend, P., Astrophys. J. (in the press).

  11. Giacconi, R., Gursky, H., Kellogg, E., Levinson, R., Schreier, E., and Tananbaum, H., Astrophys. J., 184, 227 (1973).

    Article  ADS  Google Scholar 

  12. Brecher, K., Nature, 239, 325 (1972).

    Article  ADS  Google Scholar 

  13. Doxsey, R., Bradt, H. V., Levine, A., Murthy, G. T., Rappaport, S., and Spada, G., Astrophys. J. Lett., 182, L25 (1973).

    Article  ADS  Google Scholar 

  14. Clark, G. W., Bradt, H. V., Lewin, W. H. G., Markert, T. H., Schnopper, H. W., and Sprott, G. F., Astrophys. J. Lett., 177, L109 (1972).

    Article  ADS  Google Scholar 

  15. Ulmer, M. P., Baity, W. A., Wheaton, W. A., and Peterson, L. E., Astrophys. J. Lett., 178, L61 (1972).

    Article  ADS  Google Scholar 

  16. Groth, E. J., and Nelson, M. R., Astrophys. J. Lett., 178, L111 (1972).

    Article  ADS  Google Scholar 

  17. Lamb, D. Q., and Sorvari, J. M., IAU Cire. No. 2422 (1972).

  18. Groth, E. J., Young, S. Z., Papaliolios, C., Pennypacker, C. R., Spada, G., and Middleditch, J., IAU Cire. No. 2523 (1973).

  19. Pringle, J. E., and Rees, M. J., Astr. Astrophys., 21, 1 (1972).

    ADS  Google Scholar 

  20. Davidson, K., and Ostriker, J. P., Astrophys. J., 179, 585 (1973).

    Article  ADS  Google Scholar 

  21. Lamb, F. K., Pethick, C. J., and Pines, D., Astrophys. J., 184, 271 (1973).

    Article  ADS  Google Scholar 

  22. Rosenbluth, M. N., Ruderman, M., Dyson, F., Bahcall, J. N., Shaham, J., and Ostriker, J., Astrophys. J., 184, 907 (1973).

    Article  ADS  Google Scholar 

  23. Pines, D., Pethick, C. J., and Lamb, F. K., Proc. Sixth Texas Symposium on Relativistic Astrophysics, Ann. N.Y. Acad. Sci. (in the press).

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Author information

Authors and Affiliations

  1. Institute for Advanced Study, Princeton, New Jersey, 08540

    Y. AVNI, J. N. BAHCALL & P. C. JOSS

  2. Princeton University Observatory, Princeton, New Jersey, 08540

    N. A. BAHCALL

  3. University of Illinois, Urbana, Illinois, 61801

    F. K. LAMB, C. J. PETHICK & D. PINES

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  1. Y. AVNI
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AVNI, Y., BAHCALL, J., JOSS, P. et al. Steady Energy Source in Her X-l?. Nature Physical Science 246, 36–37 (1973). https://doi.org/10.1038/physci246036a0

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  • DOI: https://doi.org/10.1038/physci246036a0

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