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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).[2]
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 expect an ejected mass of about 0.16 solar masses.
Examples

Possible examples of supernova impostors include the Great Eruption of Eta Carinae, P Cygni, SN 1961V,[3] SN 1954J, SN 1997bs, SN 2008S in NGC 6946, and SN 2010dn[1] where detections of the surviving progenitor stars are claimed.

One supernova impostor that made news after the fact was the one observed on October 20, 2004, in the galaxy UGC 4904 by Japanese amateur astronomer Koichi Itagaki. This LBV star exploded just two years later, on October 11, 2006, as supernova SN 2006jc.[4]
References

Smith, Nathan; Weidong, Li; Silverman, Jeffrey; Ganeshalingam, Mo; Filippenko, Alexei (2011). "Luminous Blue Variable eruptions and related transients: Diversity of progenitors and outburst properties". Monthly Notices of the Royal Astronomical Society. 415: 773–810.arXiv:1010.3718. Bibcode:2011MNRAS.415..773S. doi:10.1111/j.1365-2966.2011.18763.x.
Smith, Nathan; Ganeshalingam, Mohan; Chornock, Ryan; Filippenko, Alexei; Weidong, Li; et al. (2009). "SN 2008S: A Cool Super-Eddington Wind in a Supernova Impostor". Astrophysical Journal Letters. 697 (1): L49–L53.arXiv:0811.3929. Bibcode:2009ApJ...697L..49S. doi:10.1088/0004-637X/697/1/L49.
Kochanek, C.S.; Szczygiel, D.M.; Stanek, K.Z. (2010). "The Supernova Impostor Impostor SN 1961V: Spitzer Shows That Zwicky Was Right (Again)". Solar and Stellar Astrophysics. 737: 76.arXiv:1010.3704. Bibcode:2011ApJ...737...76K. doi:10.1088/0004-637X/737/2/76.

"NASA – Supernova Imposter Goes Supernova". Nasa.gov. Retrieved 2010-01-13.

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Supernovae
Classes

Type Ia Type Ib and Ic Type II (IIP, IIL, IIn, and IIb) Hypernova Superluminous Pair-instability


Physics of

Calcium-rich Carbon detonation Foe Near-Earth Phillips relationship Nucleosynthesis
P-process R-process Neutrinos

Related

Imposter
pulsational pair-instability Failed Gamma-ray burst Kilonova Luminous red nova Nova Pulsar kick Quark-nova Symbiotic nova

Progenitors

Hypergiant
yellow Luminous blue variable Supergiant
blue red yellow White dwarf
related links Wolf–Rayet star

Remnants

Supernova remnant
Pulsar wind nebula Neutron star
pulsar magnetar related links Stellar black hole
related links Compact star
quark star exotic star Zombie star Local Bubble Superbubble
Orion–Eridanus

Discovery

Guest star History of supernova observation Timeline of white dwarfs, neutron stars, and supernovae

Lists

Candidates Notable Massive stars Most distant Remnants In fiction

Notable

Barnard's Loop Cassiopeia A Crab
Crab Nebula iPTF14hls Tycho's Kepler's SN 1987A SN 185 SN 1006 SN 2003fg Remnant G1.9+0.3 SN 2007bi SN 2011fe SN 2014J SN Refsdal Vela Remnant

Research

ASAS-SN Calán/Tololo Survey High-Z Supernova Search Team Katzman Automatic Imaging Telescope Monte Agliale Supernovae and Asteroid Survey Nearby Supernova Factory Sloan Supernova Survey Supernova/Acceleration Probe Supernova Cosmology Project SuperNova Early Warning System Supernova Legacy Survey Texas Supernova Search

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Stars
Formation

Accretion Molecular cloud Bok globule Young stellar object
Protostar Pre-main-sequence Herbig Ae/Be T Tauri FU Orionis Herbig–Haro object Hayashi track Henyey track

Evolution

Main sequence Red-giant branch Horizontal branch
Red clump Asymptotic giant branch
super-AGB Blue loop Protoplanetary nebula Planetary nebula PG1159 Dredge-up OH/IR Instability strip Luminous blue variable Blue straggler Stellar population Supernova Superluminous supernova / Hypernova

Spectral classification

Early Late Main sequence
O B A F G K M Brown dwarf WR OB Subdwarf
O B Subgiant Giant
Blue Red Yellow Bright giant Supergiant
Blue Red Yellow Hypergiant
Yellow Carbon
S CN CH White dwarf Chemically peculiar
Am Ap/Bp HgMn Helium-weak Barium Extreme helium Lambda Boötis Lead Technetium Be
Shell B[e]

Remnants

White dwarf
Helium planet Black dwarf Neutron
Radio-quiet Pulsar
Binary X-ray Magnetar Stellar black hole X-ray binary
Burster

Hypothetical

Blue dwarf Green Black dwarf Exotic
Boson Electroweak Strange Preon Planck Dark Dark-energy Quark Q Black Gravastar Frozen Quasi-star Thorne–Żytkow object Iron Blitzar

Stellar nucleosynthesis

Deuterium burning Lithium burning Proton–proton chain CNO cycle Helium flash Triple-alpha process Alpha process Carbon burning Neon burning Oxygen burning Silicon burning S-process R-process Fusor Nova
Symbiotic Remnant Luminous red nova

Structure

Core Convection zone
Microturbulence Oscillations Radiation zone Atmosphere
Photosphere Starspot Chromosphere Stellar corona Stellar wind
Bubble Bipolar outflow Accretion disk Asteroseismology
Helioseismology Eddington luminosity Kelvin–Helmholtz mechanism

Properties

Designation Dynamics Effective temperature Luminosity Kinematics Magnetic field Absolute magnitude Mass Metallicity Rotation Starlight Variable Photometric system Color index Hertzsprung–Russell diagram Color–color diagram

Star systems

Binary
Contact Common envelope Eclipsing Symbiotic Multiple Cluster
Open Globular Super Planetary system

Earth-centric
observations

Sun
Solar System Sunlight Pole star Circumpolar Constellation Asterism Magnitude
Apparent Extinction Photographic Radial velocity Proper motion Parallax Photometric-standard

Lists

Proper names
Arabic Chinese Extremes Most massive Highest temperature Lowest temperature Largest volume Smallest volume Brightest
Historical Most luminous Nearest
Nearest bright With exoplanets Brown dwarfs White dwarfs Milky Way novae Supernovae
Candidates Remnants Planetary nebulae Timeline of stellar astronomy

Related articles

Substellar object
Brown dwarf Sub-brown dwarf Planet Galactic year Galaxy Guest Gravity Intergalactic Planet-hosting stars Tidal disruption event

Physics Encyclopedia

World

Index

Hellenica World - Scientific Library

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