Abstract
The microquasar SS 433 exhibits in Hα intermittent flares. A sequence of observations made in 2004 showed flaring Doppler shifted to both the red and the blue simultaneously. The mean shifts varied from day to day, following the orbital phase of the compact object. At the time, this behaviour was interpreted as indicating an origin in the outer rim of the accretion disk. A new analysis of these old data, presented in this paper, shows that the flares are not eclipsed by the Companion that eclipses the photosphere surrounding the compact object. They are therefore not intermittent sightings of an accretion disk. The alternative explanation is plasma expelled through the L2 point, following the phase of the orbit as it invades the space beyond the system. That space has been mapped with comparatively recent GRAVITY observations of a similar flare in Brγ, indeed revealing a strong rotation component.
Highlights
Flares: A New Analysis Reveals TheirThe Galactic microquasar SS 433 is famous as an example of super-Eddington mass transfer, but with most of the mass lost by the Companion ejected in the form of polar winds
General reviews are to be found in [1,2]. All these details are of particular interest because SS 433 would be classified as an Ultra-Luminous X-ray source were we looking down its throat [3], and the emission spectra of those ULX with optical counterparts are very like those of SS 433 [4]
This new analysis links optical flares in Hα with the GRAVITY flaring and a common origin: expulsion through the L2 point, because the rotational phase of the 2004 flares follow the orbital phase of the compact object
Summary
The Galactic microquasar SS 433 is famous as an example of super-Eddington mass transfer, but with most of the mass lost by the Companion ejected in the form of polar winds. These are very rough figures; fits in [5] yield supposedly orbital speeds of ~100 km s−1 at radii of ~10 A and ~1000 km s−1 at ~A Both sets of numbers are at least superficially consistent with a circumbinary disk, but the contained mass would have to be ~400 MJ for a specific angular momentum of A×1000 km s−1. It is natural to ask if the 2004 sequence of Hα flaring can cast further light on the origin, given that an accretion disk is ruled out This new analysis links optical flares in Hα with the GRAVITY flaring and a common origin: expulsion through the L2 point, because the rotational phase of the 2004 flares follow the orbital phase of the compact object.
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