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IPTF14hls
iPTF14hls is an unusual supernova star that erupted continuously for about 1,000 days beginning in September 2014 before becoming a remnant nebula. It had previously erupted in 1954. None of the theories nor proposed hypotheses fully explain all the aspects of the object. Observations The star iPTF14hls was discovered in September 2014 by the Intermediate Palomar Transient Factory, and it was first made public in November 2014 by the CRTS survey as CSS141118:092034+504148. Based on that information, it was confirmed as an exploding star in January 2015. It was thought then that it was a single supernova event ( Type II-P) that would dim in about 100 days, but instead, it continued its eruption for about 1,000 days while fluctuating in brightness at least five times. The brightness varied by as much as 50%, going through five peaks. Also, rather than cooling down with time as expected of a Type II-P supernova, the object maintains a near-constant temperature of about 500 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pulsational Pair-instability Supernova
A pulsational pair-instability supernova is a supernova impostor event that generally occurs in stars at around 100 to 130 solar mass (), as opposed to a typical pair-instability supernova which occurs in stars of 130 to . Like pair-instability supernovae, pulsational pair-instability supernovae are caused by draining of a star's energy in the production of electron-positron pairs but, whereas a pair-instability supernova completely disrupts the star in a massive supernova, the star's pulsational pair-instability eruption sheds . This generally shrinks it down to a mass of less than , too small for electron-positron pair creation, where it then undergoes a core-collapse supernova or hypernova. It is possible that this is what occurred during the 1843 eruption of the primary star of the Eta Carinae star system although there is no substantial evidence supporting this. Stellar behaviours Below Thermal gamma rays in the cores of stars of less than are not energetic enough to prod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spectral Signature
Spectral signature is the variation of reflectance or emittance of a material with respect to wavelengths (i.e., reflectance/emittance as a function of wavelength). The spectral signature of stars indicates the composition of the stellar atmosphere. The spectral signature of an object is a function of the incidental EM wavelength and material interaction with that section of the electromagnetic spectrum. The measurements can be made with various instruments, including a task specific spectrometer, although the most common method is separation of the red, green, blue and near infrared portion of the EM spectrum as acquired by digital cameras. Calibrating spectral signatures under specific illumination are collected in order to apply a correction to airborne or satellite imagery digital images. The user of one kind of spectroscope looks through it at a tube of ionized gas. The user sees specific lines of colour falling on a graduated scale. Each substance will have its own uni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SN 1993J
SN 1993J is a supernova observed in Bode's Galaxy. It was discovered on 28 March 1993 by amateur astronomer Francisco Garcia Diaz in Lugo, Spain. At the time, it was the second-brightest Type II supernova observed in the twentieth century behind SN 1987A, peaking at a visible apparent magnitude of 10.7 on March 30, with a second peak of 10.86 on April 18. The spectral characteristics of the supernova changed over time. Initially, it looked more like a Type II supernova (a supernova formed by the explosion of a giant star) with strong hydrogen spectral line emission, but later the hydrogen lines faded and strong helium spectral lines appeared, making the supernova look more like a Type Ib. Moreover, the variations in SN 1993J's luminosity over time were not like the variations observed in other Type II supernovae but did resemble the variations observed in Type Ib supernovae. Hence, the supernova has been classified as a Type IIb supernova, an intermediate class between Type II an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SN 2009ip
SN 2009ip was a supernova discovered in 2009 in the spiral galaxy NGC 7259 in the constellation of Piscis Austrinus Piscis Austrinus is a constellation in the southern celestial hemisphere. The name is Latin for "the southern fish", in contrast with the larger constellation Pisces, which represents a pair of fish. Before the 20th century, it was also known as .... Since the brightness waned after days post-discovery, it was redesignated as Luminous blue variable (LBV) supernova impostor. During the following years several luminous outbursts were detected from the SN 2009ip. In September 2012 SN 2009ip was classified as a young type IIn supernova. References Further reading * * * * * * * * * * * * * * * * * External links Light curves and spectra on thOpen Supernova Catalog Rochester Academy of Science Supernovae Astronomical objects discovered in 2009 Piscis Austrinus Luminous blue variables Long stubs with short prose {{var-star-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SN 1998S
SN 1998S was a type IIn supernova that was detected in NGC 3877 in March 1998. At the time of discovery, SN 1998S was the brightest type IIn event observed, although later outshone by SN 2010jl SN 2010jl was a luminous Type II supernova, type IIn supernova that was discovered on November 3, 2010, in the irregular galaxy UGC 5189A. It is 48.9 ± 3.4 Parsec, Mpc distant from the Solar System. It showed an infrared excess which lasted for o .... It was discovered on 1998 March 2.68 UT in NGC 3877 by Z. Wan at a broadband (unfiltered) optical magnitude of +15.2. Its spectrum showed prominent H and He emission lines with narrow peaks and broad wings, superimposed on a blue continuum. These narrow lines indicate the presence of a dense circumstellar medium (CSM) in the vicinity of the supernova. The high luminosity of SN1998S is due to the interaction of fast material (ejecta) with previously-expelled slowly-expanding material (CSM), which can more effectively convert kinetic ene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nathan Smith (astronomer)
Nathan Smith may refer to: Sports *Nathan Smith (Irish cricketer) (born 1995), Irish cricketer * Nathan Smith (New Zealand cricketer) (born 1998), New Zealand cricketer * Nathan Smith (rugby league, born 1983), Australian rugby league player for Penrith Panthers * Nathan Smith (rugby league, born 1988), Australian rugby league footballer for the Parramatta Eels * Nathan Smith (footballer, born 1987), English-born Jamaican football player *Nathan Smith (soccer, born 1994), American soccer player * Nathan Smith (footballer, born 1996), English football player * Nathan Smith (golfer) (born 1978), American amateur golfer *Nate Smith (golfer) (born 1983), American professional golfer on the Nationwide Tour * Nathan Smith (ice hockey, born 1982), Canadian NHL player * Nathan Smith (ice hockey, born 1998), American Olympic hockey player *Nathan Smith (biathlete) Nathan Smith (born 25 December 1985) is a Canadian biathlete. Career Smith competed for Canada at the 2014 Winter Olympics ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jennifer E Andrews (astronomer)
Jennifer or Jenifer may refer to: People *Jennifer (given name) *Jenifer (singer), French pop singer *Jennifer Warnes, American singer who formerly used the stage name Jennifer *Daniel of St. Thomas Jenifer *Daniel Jenifer Film and television * ''Jennifer'' (1953 film), a film starring Ida Lupino * ''Jennifer'' (1978 film), a horror film by Brice Mack * ''Jennifer'', a 1998 Ghanaian film starring Brew Riverson Jnr * "Jenifer" (''Masters of Horror''), an episode of ''Masters of Horror'' Music * The Jennifers, a British band, some of whose members later formed Supergrass * ''Jenifer'' (album), an album by French singer Jenifer * ''Jennifer'' (album), a 1972 album by Jennifer Warnes * "Jennifer", a 1974 song by Faust from ''Faust IV'' * "Jennifer", a 1983 song by Eurythmics from ''Sweet Dreams (Are Made of This)'' (album) * "Jennifer", a 2001 song by M2M from ''The Big Room'' Other uses * Hurricane Jennifer * Project Jennifer, a CIA attempt to recover a Soviet submari ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetar
A magnetar is a type of neutron star with an extremely powerful magnetic field (~109 to 1011 T, ~1013 to 1015 G). The magnetic-field decay powers the emission of high-energy electromagnetic radiation, particularly X-rays and gamma rays.Ward; Brownlee, p.286 The existence of magnetars was proposed in 1992 by Robert Duncan and Christopher Thompson following earlier work by Katz on the Soft Gamma Repeater SGR 0525-66, then called a gamma-ray burst. Their proposal sought to explain the properties of transient sources of gamma rays, now known as soft gamma repeaters (SGRs). Over the following decade, the magnetar hypothesis became widely accepted, and was extended to explain anomalous X-ray pulsars (AXPs). , 24 magnetars have been confirmed. It has been suggested that magnetars are the source of fast radio bursts (FRB), in particular as a result of findings in 2020 by scientists using the Australian Square Kilometre Array Pathfinder (ASKAP) radio telescope. Description Like ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Supernova Impostor
Supernova impostors are stellar explosions that appear at first to be a supernova but do not destroy their progenitor stars. As such, they are a class of extra-powerful novae. They are also known as Type V supernovae, Eta Carinae analogs, and giant eruptions of luminous blue variables (LBV). Appearance, origin and mass loss Supernova impostors appear as remarkably faint supernovae of spectral type IIn—which have hydrogen in their spectrum and narrow spectral lines that indicate relatively low gas speeds. These impostors exceed their pre-outburst states by several magnitudes, with typical peak absolute visual magnitudes of −11 to −14, making these outbursts as bright as the most luminous stars. The trigger mechanism of these outbursts remains unexplained, though it is thought to be caused by violating the classical Eddington luminosity limit, initiating severe mass loss. If the ratio of radiated energy to kinetic energy is near unity, as in Eta Carinae, then we might e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antimatter
In modern physics, antimatter is defined as matter composed of the antiparticles (or "partners") of the corresponding subatomic particle, particles in "ordinary" matter, and can be thought of as matter with reversed charge and parity, or going backward in time (see CPT symmetry). Antimatter occurs in natural processes like cosmic ray collisions and some types of radioactive decay, but only a tiny fraction of these have successfully been bound together in experiments to form antiatoms. Minuscule numbers of antiparticles can be generated at particle accelerators, but total artificial production has been only a few nanograms. No Macroscopic scale, macroscopic amount of antimatter has ever been assembled due to the extreme cost and difficulty of production and handling. Nonetheless, antimatter is an essential component of widely available applications related to beta decay, such as positron emission tomography, radiation therapy, and industrial imaging. In theory, a particle and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photosphere
The photosphere is a star's outer shell from which light is radiated. It extends into a star's surface until the plasma becomes opaque, equivalent to an optical depth of approximately , or equivalently, a depth from which 50% of light will escape without being scattered. A photosphere is the region of a luminous object, usually a star, that is transparent to photons of certain wavelengths. Stars, except neutron stars, have no solid or liquid surface. Therefore, the photosphere is typically used to describe the Sun's or another star's visual surface. Etymology The term ''photosphere'' is derived from Ancient Greek roots, φῶς, φωτός/''phos'', ''photos'' meaning "light" and σφαῖρα/''sphaira'' meaning "sphere", in reference to it being a spherical surface that is perceived to emit light. Temperature The surface of a star is defined to have a temperature given by the effective temperature in the Stefan–Boltzmann law. Various stars have photospheres of vari ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
