SS 433
Encyclopedia
SS 433 is one of the most exotic star system
s observed. It is an eclipsing X-ray binary
system, with the primary most likely a black hole
, or possibly a neutron star
., pp. 23–24. The spectrum of the secondary companion star suggests that it is a late A-type star. SS 433 is a microquasar, the first discovered.
SS 433's designation comes from its catalogers, Case Western Reserve astronomers Nicholas Sanduleak
and C. Bruce Stephenson. It was the 433rd entry in their 1977 catalog of stars with strong emission lines.
W50
, which is thought to be approximately 10,000 years old. The primary, whether black hole or neutron star, is the remnant collapsed stellar core of the supernova explosion which created W50
. SS 433 is located approximately 18,000 light-year
s away from us, in the constellation of Aquila
, is 14th magnitude in the visible spectrum
, and is both an X-ray
and a radio source.
formed around the central object. The accretion disc is subject to extreme heating as it spirals into the primary and this heating causes the accretion disc to give off intense X-rays and opposing jets of hot hydrogen along the axis of rotation, above and below the plane of the accretion disc. The material in the jets travels at 26% of the speed of light
., pp. 23–24; , p. 508. The companion star presumably had lower mass than the original primary object and was therefore longer lived. Estimates for its mass range from 3, p. 25 to 30 solar mass
es. The primary and secondary orbit each other at a very close distance in stellar terms, with an orbital period of 13.1 days., p. 510.
around an axis inclined about 79° to a line between us and SS 433. The angle between the jets and the axis is around 20°, and the precessional period is around 162.5 days. Precession means that the jets sometimes point more towards the Earth, and sometimes more away, producing both blue and red Doppler shifts in the observed visible spectrum., p. 508. Also, the precession means that the jets corkscrew through space in an expanding helical spray. As they impact the supernova remnant clouds, they distort W50 into an elongated shape.
Observations in 2004 by the Very Long Baseline Array
for 42 consecutive days gave new data and understanding of the action of the jets. It appears that the jets are sometimes impacting material shortly after being created and thus brightening. The material the jets are impacting appears to be replaced some of the time, but not always, leading to variations in the brightening of the jets.
The spectrum of SS 433 is affected not just by Doppler shifts but also by relativity
: when the effects of the Doppler shift are subtracted, there is a residual redshift which corresponds to a velocity of about 12,000 kilometers per second
. This does not represent an actual velocity of the system away from the Earth; rather, it is due to time dilation
, which makes moving clocks appear to stationary observers to be ticking more slowly. In this case, the relativistically moving excited atoms in the jets appear to vibrate more slowly and their radiation thus appears red-shifted., p. 508.
Star system
A star system or stellar system is a small number of stars which orbit each other, bound by gravitational attraction. A large number of stars bound by gravitation is generally called a star cluster or galaxy, although, broadly speaking, they are also star systems.-Binary star systems:A stellar...
s observed. It is an eclipsing X-ray binary
X-ray binary
X-ray binaries are a class of binary stars that are luminous in X-rays.The X-rays are produced by matter falling from one component, called the donor to the other component, called the accretor, which is compact: a white dwarf, neutron star, or black hole.The infalling matter releases...
system, with the primary most likely a black hole
Black hole
A black hole is a region of spacetime from which nothing, not even light, can escape. The theory of general relativity predicts that a sufficiently compact mass will deform spacetime to form a black hole. Around a black hole there is a mathematically defined surface called an event horizon that...
, or possibly a neutron star
Neutron star
A neutron star is a type of stellar remnant that can result from the gravitational collapse of a massive star during a Type II, Type Ib or Type Ic supernova event. Such stars are composed almost entirely of neutrons, which are subatomic particles without electrical charge and with a slightly larger...
., pp. 23–24. The spectrum of the secondary companion star suggests that it is a late A-type star. SS 433 is a microquasar, the first discovered.
SS 433's designation comes from its catalogers, Case Western Reserve astronomers Nicholas Sanduleak
Nicholas Sanduleak
Nicholas Sanduleak was an American astronomer.-Biography:Sanduleak's parents were born in Romania. His family moved to Cleveland soon after he was born, where Sanduleak did undergraduate work at the Case Institute of Technology, receiving a B.S. in 1956...
and C. Bruce Stephenson. It was the 433rd entry in their 1977 catalog of stars with strong emission lines.
Location
SS 433 lies within supernova remnantSupernova remnant
A supernova remnant is the structure resulting from the explosion of a star in a supernova. The supernova remnant is bounded by an expanding shock wave, and consists of ejected material expanding from the explosion, and the interstellar material it sweeps up and shocks along the way.There are two...
W50
W50 (nebula)
W50 or SNR G039.7-02.0 is a Supernova remnant located in the Aquila constellation, about 18,000 light years away. In its centre lies the micro-quasar SS 433, whose jets are distorting the remnant's shell. Most likely W50 and SS443 are related objects, remnants from a supernova which occurred about...
, which is thought to be approximately 10,000 years old. The primary, whether black hole or neutron star, is the remnant collapsed stellar core of the supernova explosion which created W50
W50 (nebula)
W50 or SNR G039.7-02.0 is a Supernova remnant located in the Aquila constellation, about 18,000 light years away. In its centre lies the micro-quasar SS 433, whose jets are distorting the remnant's shell. Most likely W50 and SS443 are related objects, remnants from a supernova which occurred about...
. SS 433 is located approximately 18,000 light-year
Light-year
A light-year, also light year or lightyear is a unit of length, equal to just under 10 trillion kilometres...
s away from us, in the constellation of Aquila
Aquila (constellation)
Aquila is a stellar constellation. Its name is Latin for 'eagle' and it is commonly represented as such. In mythology, Aquila was owned by the Roman god Jupiter and performed many tasks for him....
, is 14th magnitude in the visible spectrum
Visible spectrum
The visible spectrum is the portion of the electromagnetic spectrum that is visible to the human eye. Electromagnetic radiation in this range of wavelengths is called visible light or simply light. A typical human eye will respond to wavelengths from about 390 to 750 nm. In terms of...
, and is both an X-ray
X-ray
X-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma...
and a radio source.
System
The compact central object is consuming the companion star which rapidly loses mass into an accretion discAccretion disc
An accretion disc is a structure formed by diffuse material in orbital motion around a central body. The central body is typically a star. Gravity causes material in the disc to spiral inward towards the central body. Gravitational forces compress the material causing the emission of...
formed around the central object. The accretion disc is subject to extreme heating as it spirals into the primary and this heating causes the accretion disc to give off intense X-rays and opposing jets of hot hydrogen along the axis of rotation, above and below the plane of the accretion disc. The material in the jets travels at 26% of the speed of light
Speed of light
The speed of light in vacuum, usually denoted by c, is a physical constant important in many areas of physics. Its value is 299,792,458 metres per second, a figure that is exact since the length of the metre is defined from this constant and the international standard for time...
., pp. 23–24; , p. 508. The companion star presumably had lower mass than the original primary object and was therefore longer lived. Estimates for its mass range from 3, p. 25 to 30 solar mass
Solar mass
The solar mass , , is a standard unit of mass in astronomy, used to indicate the masses of other stars and galaxies...
es. The primary and secondary orbit each other at a very close distance in stellar terms, with an orbital period of 13.1 days., p. 510.
Observational data
The jets from the primary are emitted perpendicular to its accretion disk. The jets and disk precessPrecession
Precession is a change in the orientation of the rotation axis of a rotating body. It can be defined as a change in direction of the rotation axis in which the second Euler angle is constant...
around an axis inclined about 79° to a line between us and SS 433. The angle between the jets and the axis is around 20°, and the precessional period is around 162.5 days. Precession means that the jets sometimes point more towards the Earth, and sometimes more away, producing both blue and red Doppler shifts in the observed visible spectrum., p. 508. Also, the precession means that the jets corkscrew through space in an expanding helical spray. As they impact the supernova remnant clouds, they distort W50 into an elongated shape.
Observations in 2004 by the Very Long Baseline Array
Very Long Baseline Array
The Very Long Baseline Array is a system of ten radio telescopes controlled remotely from the Array Operations Center in Socorro, New Mexico by the National Radio Astronomy Observatory. The array works together as the world's largest dedicated, full-time astronomical instrument using the...
for 42 consecutive days gave new data and understanding of the action of the jets. It appears that the jets are sometimes impacting material shortly after being created and thus brightening. The material the jets are impacting appears to be replaced some of the time, but not always, leading to variations in the brightening of the jets.
The spectrum of SS 433 is affected not just by Doppler shifts but also by relativity
Special relativity
Special relativity is the physical theory of measurement in an inertial frame of reference proposed in 1905 by Albert Einstein in the paper "On the Electrodynamics of Moving Bodies".It generalizes Galileo's...
: when the effects of the Doppler shift are subtracted, there is a residual redshift which corresponds to a velocity of about 12,000 kilometers per second
Second
The second is a unit of measurement of time, and is the International System of Units base unit of time. It may be measured using a clock....
. This does not represent an actual velocity of the system away from the Earth; rather, it is due to time dilation
Time dilation
In the theory of relativity, time dilation is an observed difference of elapsed time between two events as measured by observers either moving relative to each other or differently situated from gravitational masses. An accurate clock at rest with respect to one observer may be measured to tick at...
, which makes moving clocks appear to stationary observers to be ticking more slowly. In this case, the relativistically moving excited atoms in the jets appear to vibrate more slowly and their radiation thus appears red-shifted., p. 508.
Further reading
- Observations of SS 433, Bruce Margon, in Annual review of astronomy and astrophysics, volume 22, Palo Alto, CA: Annual Reviews, Inc., 1984, pp. 507–536. DOI 10.1146/annurev.aa.22.090184.002451.
- The Quest for SS433, David H. Clark. New York: Viking, 1985. ISBN 0-670-80388-X.
- High-mass X-ray binary
- Image SS 433