SCP 06F6
Encyclopedia
Astronomical object
Astronomical objects or celestial objects are naturally occurring physical entities, associations or structures that current science has demonstrated to exist in the observable universe. The term astronomical object is sometimes used interchangeably with astronomical body...
of unknown type, discovered on 21 February 2006 in the constellation Boötes
Boötes
Boötes is a constellation in the northern sky, located between 0° and +60° declination, and 13 and 16 hours of right ascension on the celestial sphere. The name comes from the Greek Βοώτης, Boōtēs, meaning herdsman or plowman...
during a survey of galaxy cluster
Galaxy cluster
A galaxy cluster is a compact cluster of galaxies. Basic difference between a galaxy group and a galaxy cluster is that there are many more galaxies in a cluster than in a group. Also, galaxies in a cluster are more compact and have higher velocity dispersion. One of the key features of cluster is...
CL 1432.5+3332.8 with the Hubble Space Telescope
Hubble Space Telescope
The Hubble Space Telescope is a space telescope that was carried into orbit by a Space Shuttle in 1990 and remains in operation. A 2.4 meter aperture telescope in low Earth orbit, Hubble's four main instruments observe in the near ultraviolet, visible, and near infrared...
's Advanced Camera for Surveys
Advanced Camera for Surveys
The Advanced Camera for Surveys is a third generation axial instrument aboard the Hubble Space Telescope . The initial design and scientific capabilities of ACS were defined by a team based at Johns Hopkins University. ACS was assembled and tested extensively at Ball Aerospace & Technologies Corp...
Wide Field Channel.
According to research authored by Kyle Barbary of the Supernova Cosmology Project
Supernova Cosmology Project
The Supernova Cosmology Project is one of two research teams that determined the likelihood of an accelerating universe and therefore a positive Cosmological constant, using data from the redshift of Type Ia supernovae...
, the object brightened over a period of roughly 100 days, reaching a peak intensity of magnitude
Apparent magnitude
The apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, adjusted to the value it would have in the absence of the atmosphere...
21; it then faded over a similar period.
Barbary et al. report that the spectrum
Spectrum
A spectrum is a condition that is not limited to a specific set of values but can vary infinitely within a continuum. The word saw its first scientific use within the field of optics to describe the rainbow of colors in visible light when separated using a prism; it has since been applied by...
of light emitted from the object does not match known supernova
Supernova
A supernova is a stellar explosion that is more energetic than a nova. It is pronounced with the plural supernovae or supernovas. Supernovae are extremely luminous and cause a burst of radiation that often briefly outshines an entire galaxy, before fading from view over several weeks or months...
types, and is dissimilar to any known phenomena
Phenomenon
A phenomenon , plural phenomena, is any observable occurrence. Phenomena are often, but not always, understood as 'appearances' or 'experiences'...
in the Sloan Digital Sky Survey
Sloan Digital Sky Survey
The Sloan Digital Sky Survey or SDSS is a major multi-filter imaging and spectroscopic redshift survey using a dedicated 2.5-m wide-angle optical telescope at Apache Point Observatory in New Mexico, United States. The project was named after the Alfred P...
database. The light in the blue region shows broad line features, while the red region shows continuous emission. The spectrum shows a handful of spectral lines, but when astronomers try to trace any one of them to an element the other lines fail to match up with any other known elements.
Because of its uncommon spectrum, the team was not able to determine the distance to the object using standard redshift
Redshift
In physics , redshift happens when light seen coming from an object is proportionally increased in wavelength, or shifted to the red end of the spectrum...
techniques; it is not even known whether the object is within or outside the Milky Way. Furthermore, no Milky Way star or external galaxy has been detected at this location, meaning any source is very faint.
The European X-ray satellite XMM Newton made an observation in early August 2006 which appears to show an X-ray glow around SCP 06F6, two orders of magnitude more luminous than that of supernovae.
Observations from the Palomar Transient Factory
Palomar Transient Factory
The Palomar Transient Factory is an astronomical wide-field survey designed to search for optical transient and variable sources. It is fully automated, including a wide-field survey camera, an automated realtime data reduction pipeline, a dedicated photometric follow up telescope, and a full...
reported in 2009, indicate a redshift z = 1.189 and a peak magnitude of −23.5 absolute (comparable to SN2005ap) making SCP 06F6 one of the most luminous transient phenomenon known as of that date.
Possible causes
Supernovae reach their maximum brightness in only 20 days, and then take much longer to fade away. Researchers had initially conjectured that SCP 06F6 might be an extremely remote supernova; relativistic time dilation might have caused a 20-day event to stretch out over a period of 100 days. But this explanation now seems unlikely. Other conjectures that have been advanced involve a collision between a white dwarfWhite dwarf
A white dwarf, also called a degenerate dwarf, is a small star composed mostly of electron-degenerate matter. They are very dense; a white dwarf's mass is comparable to that of the Sun and its volume is comparable to that of the Earth. Its faint luminosity comes from the emission of stored...
and an asteroid
Asteroid
Asteroids are a class of small Solar System bodies in orbit around the Sun. They have also been called planetoids, especially the larger ones...
, or the collision of a white dwarf with a black hole.
An analysis by a team from the University of Warwick
University of Warwick
The University of Warwick is a public research university located in Coventry, United Kingdom...
(Boris Gänsicke et al.) suggests that the light spectrum is "consistent with emission from a cool, carbon
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
-rich atmosphere at a redshift
Redshift
In physics , redshift happens when light seen coming from an object is proportionally increased in wavelength, or shifted to the red end of the spectrum...
of z~0.14", possibly representing the core collapse and explosion of a carbon star
Carbon star
A carbon star is a late-type star similar to a red giant whose atmosphere contains more carbon than oxygen; the two elements combine in the upper layers of the star, forming carbon monoxide, which consumes all the oxygen in the atmosphere, leaving carbon atoms free to form other carbon compounds,...
. Gänsicke's group concurs with Barbary et al. that SCP 06F6 may represent "a new class" of celestial object.
The analysis of Israeli astronomers of Technion, suggest four alternative explanations for SCP 06F6, in plausibility order: the tidal destruction of a CO white dwarf
White dwarf
A white dwarf, also called a degenerate dwarf, is a small star composed mostly of electron-degenerate matter. They are very dense; a white dwarf's mass is comparable to that of the Sun and its volume is comparable to that of the Earth. Its faint luminosity comes from the emission of stored...
by an intermediate-mass 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...
, a type Ia
Type Ia supernova
A Type Ia supernova is a sub-category of supernovae, which in turn are a sub-category of cataclysmic variable stars, that results from the violent explosion of a white dwarf star. A white dwarf is the remnant of a star that has completed its normal life cycle and has ceased nuclear fusion...
supernova
Supernova
A supernova is a stellar explosion that is more energetic than a nova. It is pronounced with the plural supernovae or supernovas. Supernovae are extremely luminous and cause a burst of radiation that often briefly outshines an entire galaxy, before fading from view over several weeks or months...
exploding inside the dense stellar wind of a carbon star
Carbon star
A carbon star is a late-type star similar to a red giant whose atmosphere contains more carbon than oxygen; the two elements combine in the upper layers of the star, forming carbon monoxide, which consumes all the oxygen in the atmosphere, leaving carbon atoms free to form other carbon compounds,...
, an asteroid
Asteroid
Asteroids are a class of small Solar System bodies in orbit around the Sun. They have also been called planetoids, especially the larger ones...
that was swallowed up by a white dwarf or, least likely, a core collapse supernova
Type II supernova
A Type II supernova results from the rapid collapse and violent explosion of a massive star. A star must have at least 9 times, and no more than 40–50 times the mass of the Sun for this type of explosion. It is distinguished from other types of supernova by the presence of hydrogen in its spectrum...
.
Observations in 2009 indicate that it may be a pair-instability supernova
Pair-instability supernova
A pair-instability supernova occurs when pair production, the production of free electrons and positrons in the collision between atomic nuclei and energetic gamma rays, reduces thermal pressure inside a supermassive star's core...
.
The event was similar to SN 2005ap
SN 2005ap
SN 2005ap was an extremely energetic type II supernova. It is reported to be the brightest supernova yet recorded, twice as bright as the previous record holder, SN 2006gy...
, and other unusually bright supernova suggesting that it was a new type of supernova.