The following document lists the file abstract/ASALAMA_SS433.abs
from catalogue VI/111.
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SCIENTIFIC ABSTRACT We propose to study the infrared spectral variability of the peculiar object SS433, a binary system and black hole candidate from which plasma is ejected at 0.26c in two oppositly directed, precessing jets. Despite copious observations performed since its discovery in 1978 at many wavelengths, the physical nature of the black-hole candidate SS433 is still uncertain. The IRAS (12, 25 micron) and ground-based NIR observations indicate that a turnover in the energy distribution will be found in the ISO wavelength range. Proposed explanationss could be either free-free emission from an ionized plasma or thermal emission from an accretion disk. With our PHT observations (using PHT-S, -P and -C), some of which will be repeated within the binary and precessional cycles, we aim to derive observational constraints to the theories that model the shape and physical properties of the emitting region. OBSERVATION SUMMARY The IR emission of SS433 will be measured with PHT-S (both ranges), PHT-P (in the 11.5, 25 and 60 micron filters) and PHT-C (in the C_100 filter), as CONCATENATED OBSERVATIONS. Half-way through the precessional cycle of 163 days, the PHT-S observations should be repeated 3 times, equally spaced within the binary cycle of 13 days. The requested S/N is at least 10 for all observations, which are chopped, in Triangular mode, with a throw of 90 arcsec with PHT-S, 120 arcsec with PHT-P and 150 arcs with PHT-C. Diffraction limited apertures of 18, 52 and 99 arcsec will be used with the 11.5, 25 and 60 microns filters, respectively.