Intermediate Luminosity Red Transient
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Intermediate Luminosity Red Transients (ILRT), is a subclass of stellar transients that occupy the luminosity gap between classical nova and typical supernovae.[1][2]
ILRTs are part of the broader category of Intermediate Luminosity Optical Transient or gap transients, which include diverse phenomena such as luminous red nova and supernova impostors. However, ILRTs are distinguished by their spectroscopic features and light curve shapes, often resembling faint Type II supernovae.[3][4]
Progenitors
Progenitors are dust-enshrouded, detected primarily in MIR but faint or undetected in optical pre-explosion images. Estimated masses are 8–12 M⊙, consistent with super-asymptotic giant branch (super-AGB) stars.[5][6]
Late-time observations show some ILRTs fading below progenitor luminosity in MIR, supporting terminal explosions.[7]
The favored explanation is electron capture supernova in a super-AGB stars with degenerate O-Ne-Mg cores. Electron capture on Ne and Mg reduces pressure support, triggering collapse.[1][8]
Alternatives include non-terminal outbursts or mergers, but fading below progenitor levels and low yields favor terminal electron capture supernova.[9]
