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SS 433:
Chandra Reveals Pileup on Cosmic Speedway
The most recent Chandra image of SS 433 shows two
high speed lobes of 50 million degree gas 5 trillion
kilometers apart on opposite sides of a binary black
hole system. As shown in the illustration (lower
right), the binary system, which has a diameter several
million times smaller than the distance between the
lobes, consists of a massive star and a black hole with
a disk of hot matter. Material is ejected from this disk in narrow jets that slowly wobble or precess around a circle (represented by blue circular arrow), from the sketched location of the jet at one extreme to the dotted white line at another.
The detection of the hot gas lobes so far away from
the central black hole came as a surprise since earlier
observations by Chandra and the Hubble Space Telescope
had indicated that gas was cooling as it expanded away
from the vicinity of the black hole in narrow jets.
This led scientists to predict that no hot gas would be
found further than a few million kilometers from the
black hole.
This observation implies that the gas in the jets has
been reheated, most likely by collisions between blobs
of gas. Long-term optical monitoring observations have
shown that matter is ejected every few minutes from the
vicinity of the black hole in bullet-like gaseous
blobs. The blobs apparently travel outward at about a
quarter of the speed of light for several months
without colliding until a faster blob rear-ends a
slower one, precipitating a pileup that reheats the
gas.
SS 433 is similar to the XTE
J1550-564 binary system, in that they both involve
black holes that are producing high speed jets of gas.
However, there are significant differences. The X-ray
emitting lobes in XTE J1550 are observed to be much
further from the black hole than those in SS 433, and
the X-rays from the XTE J1550 lobes appear to be
produced by a magnetized cloud of highly energetic
electrons, not clouds of hot gas as in SS 433. These
differences might be due to the mass of the companion
stars, which are quite dissimilar. In XTE J1550, the
companion star has a mass similar to that of the Sun,
whereas in SS 433, the companion star's mass is
estimated to be almost 20 times that of the Sun.
Perhaps the rapid rate of evaporation of matter from
the massive star could affect the behavior of the jets
in SS 433.
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Fast Facts for SS
433:
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Credit
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NASA/CXC/U.Amsterdam/S.Migliari et
al.
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Scale
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Image is 6.5 arcsec across
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Category
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Black
Holes
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Coordinates
(J2000)
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RA 19h 11m 49.5s | Dec +04º 58'
58" |
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Constellation
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Aquila
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Observation
Date
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June 27, 2000
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Observation
Time
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2.7 hours
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Obs.
ID
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659
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Color
Code
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Intensity
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Instrument
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ACIS
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Distance
Estimate
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About 16,000 light years
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Release Date
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December 11, 2002
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