An Intermediate Luminosity Optical Transient (ILOT) is an astronomical object which undergoes an optically detectable explosive event with an

absolute magnitude Absolute magnitude () is a measure of the luminosity of a celestial object on an inverse Logarithmic scale, logarithmic Magnitude (astronomy), astronomical magnitude scale. An object's absolute magnitude is defined to be equal to the apparent mag ...

(''M'') brighter than a

classical nova A nova (plural novae or novas) is a transient astronomical event that causes the sudden appearance of a bright, apparently "new" star (hence the name "nova", which is Latin for "new") that slowly fades over weeks or months. Causes of the dramat ...

(''M'' ~ -8) but fainter than that of a supernova (''M'' ~ -17). That nine magnitude range corresponds to a factor of nearly 4000 in luminosity, so the ILOT class may include a wide variety of objects. The term ILOT first appeared in a 2009 paper discussing the nova-like event NGC 300 OT2008-1. As the term has gained more widespread use, it has begun to be applied to some objects like

KjPn 8 KjPn 8 is a bipolar planetary nebula which was discovered by M.A. Kazaryan and Eh. S. Parsamyan in 1971 and independently by Luboš Kohoutek in 1972. Very little was published about this nebula until 1995, when it was realized that KjPn 8 sits i ...

and

CK Vulpeculae CK Vulpeculae (also Nova Vulpeculae 1670) is an object whose exact nature is unknown. It was once considered to be the oldest reliably-documented nova. It consists of a compact central object surrounded by a bipolar nebula. Models sugge ...

for which no transient event has been observed, but which may have been dramatically affected by an ILOT event in the past. The number of ILOTs known is expected to increase substantially when the

Vera C. Rubin Observatory The Vera C. Rubin Observatory, previously referred to as the Large Synoptic Survey Telescope (LSST), is an astronomical observatory currently under construction in Chile. Its main task will be carrying out a synoptic astronomical survey, the L ...

becomes operational. A very wide variety of objects have been classified as ILOTs in the astronomical literature. Kashi and Soker proposed a model for the outburt of ASASSN-15qi, in which a Jupiter-mass planet is tidally destroyed and accreted onto a young

main sequence In astronomy, the main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Her ...

star. Red novae, believed be caused by the merger of two stars, are classified as ILOTs. Some

luminous blue variable Luminous blue variables (LBVs) are massive evolved stars that show unpredictable and sometimes dramatic variations in their spectra and brightness. They are also known as S Doradus variables after S Doradus, one of the brightest stars of the Larg ...

s, such as η Car have been classified as ILOTs. Some objects which have been classified as

failed supernova A failed supernova is an astronomical event in time domain astronomy in which a star suddenly brightens as in the early stage of a supernova, but then does not increase to the massive flux of a supernova. They could be counted as a subcategory of ...

e may be ILOTs. The common thread tying all of these objects together is a transfer of a large amount of mass (0.001 M_⊙ to a few M_⊙) from a planet or star to a companion star, over a short period of time, leading to a massive eruption. That large range in accretion mass explains the large range in ILOT event brightness.

References

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External links

The ILOT Club
Stellar phenomena Astronomical events

See also

References

External links