Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
---|---|
Constellation | Ursa Minor |
Right ascension | 14h 12m 55.867s [1] |
Declination | +79° 22′ 03.895″ [1] |
Characteristics | |
Evolutionary stage | Neutron star |
Astrometry | |
Distance | ≤2000 [1] pc |
Details [1] | |
Rotation | 59.199071070 ms |
Age | 285,000 years |
Other designations | |
Database references | |
SIMBAD | data |
In astronomy, Calvera (also known as 1RXS J141256.0+792204 [3] ) is an X-ray source in the constellation Ursa Minor, identified in 2007 as an isolated neutron star. [4] [5] It is one of the hottest [6] and closest of its kind to Earth. [7]
It is named after the villain in the 1960 film The Magnificent Seven , as it is the eighth such neutron star known within 500 parsecs of Earth, and the seven previously discovered isolated neutron stars are called 'The Magnificent Seven'.
There is a ring of radio emission almost a degree in diameter, offset about 4′.9 from Calvera itself, which is possibly its supernova remnant. [8]
A neutron star is the collapsed core of a massive supergiant star, which had a total mass of between 10 and 25 solar masses (M☉), possibly more if the star was especially metal-rich. Except for black holes, neutron stars are the smallest and densest known class of stellar objects. Neutron stars have a radius on the order of 10 kilometers (6 mi) and a mass of about 1.4 M☉. They result from the supernova explosion of a massive star, combined with gravitational collapse, that compresses the core past white dwarf star density to that of atomic nuclei.
A supernova is a powerful and luminous explosion of a star. A supernova occurs during the last evolutionary stages of a massive star or when a white dwarf is triggered into runaway nuclear fusion. The original object, called the progenitor, either collapses to a neutron star or black hole, or is completely destroyed to form a diffuse nebula. The peak optical luminosity of a supernova can be comparable to that of an entire galaxy before fading over several weeks or months.
A super-luminous supernova is a type of stellar explosion with a luminosity 10 or more times higher than that of standard supernovae. Like supernovae, SLSNe seem to be produced by several mechanisms, which is readily revealed by their light-curves and spectra. There are multiple models for what conditions may produce an SLSN, including core collapse in particularly massive stars, millisecond magnetars, interaction with circumstellar material, or pair-instability supernovae.
A stellar black hole is a black hole formed by the gravitational collapse of a star. They have masses ranging from about 5 to several tens of solar masses. The process is observed as a hypernova explosion or as a gamma ray burst. These black holes are also referred to as collapsars.
3C 58 or 3C58 is a pulsar and supernova remnant within the Milky Way. The object is listed as No. 58 in the Third Cambridge Catalogue of Radio Sources.
A pulsar is a highly magnetized rotating neutron star that emits beams of electromagnetic radiation out of its magnetic poles. This radiation can be observed only when a beam of emission is pointing toward Earth, and is responsible for the pulsed appearance of emission. Neutron stars are very dense and have short, regular rotational periods. This produces a very precise interval between pulses that ranges from milliseconds to seconds for an individual pulsar. Pulsars are one of the candidates for the source of ultra-high-energy cosmic rays.
A millisecond pulsar (MSP) is a pulsar with a rotational period less than about 10 milliseconds. Millisecond pulsars have been detected in radio, X-ray, and gamma ray portions of the electromagnetic spectrum. The leading theory for the origin of millisecond pulsars is that they are old, rapidly rotating neutron stars that have been spun up or "recycled" through accretion of matter from a companion star in a close binary system. For this reason, millisecond pulsars are sometimes called recycled pulsars.
Cassiopeia A (Cas A) is a supernova remnant (SNR) in the constellation Cassiopeia and the brightest extrasolar radio source in the sky at frequencies above 1 GHz. The supernova occurred approximately 11,000 light-years (3.4 kpc) away within the Milky Way; given the width of the Orion Arm, it lies in the next-nearest arm outwards, the Perseus Arm, about 30 degrees from the Galactic anticenter. The expanding cloud of material left over from the supernova now appears approximately 10 light-years (3 pc) across from Earth's perspective. It has been seen in wavelengths of visible light with amateur telescopes down to 234 mm (9.25 in) with filters.
W49B is a nebula in Westerhout 49 (W49). The nebula is a supernova remnant, probably from a type Ib or Ic supernova that occurred around 1,000 years ago. It may have produced a gamma-ray burst and is thought to have left a black hole remnant.
The Hulse–Taylor pulsar is a binary star system composed of a neutron star and a pulsar which orbit around their common center of mass. It is the first binary pulsar ever discovered.
A binary pulsar is a pulsar with a binary companion, often a white dwarf or neutron star. Binary pulsars are one of the few objects which allow physicists to test general relativity because of the strong gravitational fields in their vicinities. Although the binary companion to the pulsar is usually difficult or impossible to observe directly, its presence can be deduced from the timing of the pulses from the pulsar itself, which can be measured with extraordinary accuracy by radio telescopes.
The Tolman–Oppenheimer–Volkoff limit is an upper bound to the mass of cold, non-rotating neutron stars, analogous to the Chandrasekhar limit for white dwarf stars. If the mass of a neutron star reaches the limit it will collapse to a denser form, most likely a black hole.
A radio-quiet neutron star is a neutron star that does not seem to emit radio emissions, but is still visible to Earth through electromagnetic radiation at other parts of the spectrum, particularly X-rays and gamma rays.
PSR B1828-11 is a pulsar approximately 10,000 light-years away in the constellation of Scutum. The star exhibits variations in the timing and shape of its pulses: this was at one stage interpreted as due to a possible planetary system in orbit around the pulsar, though the model required an anomalously large second period derivative of the pulse times. The planetary model was later discarded in favour of precession effects as the planets could not cause the observed shape variations of the pulses. While the generally accepted model is that the pulsar is a neutron star undergoing free precession, a model has been proposed that interprets the pulsar as a quark star undergoing forced precession due to an orbiting "quark planet". The entry for the pulsar on SIMBAD lists this hypothesis as being controversial.
1RXS J160929.1−210524 is a pre-main-sequence star approximately 456 light-years away in the constellation of Scorpius.
PSR B1937+21 is a pulsar located in the constellation Vulpecula a few degrees in the sky away from the first discovered pulsar, PSR B1919+21. The name PSR B1937+21 is derived from the word "pulsar" and the declination and right ascension at which it is located, with the "B" indicating that the coordinates are for the 1950.0 epoch. PSR B1937+21 was discovered in 1982 by Don Backer, Shri Kulkarni, Carl Heiles, Michael Davis, and Miller Goss.
PSR J0108−1431 is a solitary pulsar located at a distance of about 130 parsecs (424 light-years) in the constellation Cetus. This pulsar was discovered in 1994 during the Parkes Southern Pulsar Survey. It is considered a very old pulsar with an estimated age of 166 million years and a rotation period of 0.8 seconds. The rotational energy being generated by the spin-down of this pulsar is 5.8 × 1023 W and the surface magnetic field is 2.5 × 107 T. As of 2008, it is the second faintest known pulsar.
PSR J0348+0432 is a pulsar–white dwarf binary system in the constellation Taurus. It was discovered in 2007 with the National Radio Astronomy Observatory's Robert C. Byrd Green Bank Telescope in a drift-scan survey.
PSR J0659+1414 is a pulsar. It produces single peaked pulsed gamma rays.