Photometric observations of the radio bright B[e]/X-ray binary CI Cam

UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
Anatoly S. Miroshnichenko, Associate Professor (Creator)
Institution
The University of North Carolina at Greensboro (UNCG )
Web Site: http://library.uncg.edu/

Abstract: We present multiwavelength (optical, IR, radio) observations of CI Cam, the optical counterpart to the transient X-ray source XTE J0421+560. Pre-outburst quiescent observations reveal the presence of a dusty envelope around the system. Pronounced short term variability is observed at all wavebands from U–K, but no indication of prior flaring of a similar magnitude to the 1998 April outburst is found in these data. Data obtained during the 1998 April X-ray flare reveal pronounced optical-radio flaring. The optical flux was observed to quickly return to quiescent levels, while the radio flare was of much longer duration. The optical component is likely to result from a combination of free–free/free–bound emission, emission line and thermal dust emission, caused by re-radiation of the Xray flux, while the behaviour of the multiwavelength radio data is consistent with emission from expanding eject a emitting via the synchrotron mechanism. Post-outburst (1998 August–1999 March) U–M broadband photometric observations reveal that while the optical (UBV ) flux remains at pre-outburst quiescent levels, near IR (JHKLM) fluxes exceed the pre-outburst fluxes by ~0.5 magnitudes. Modelling the pre- and post-outburst spectral energy distribution of CI Cam reveals that the structure and/or composition of the dusty component of the circumstellar envelope appears to have changed. Due to a lack of information on the precise chemical composition of the dust within the system several explanations for this behaviour are possible, such as the produc-tion of newdust at the inner edge of the envelope, or modification of the composition of the dust due to X-ray irradiation.

Additional Information

Publication
Astronomy and Astrophysics 356, 50–62 (2000)
Language: English
Date: 2000
Keywords
stars: binaries: general, stars: circumstellar matter, stars: individual: CI Cam, stars: winds, outflows, X-rays: stars