NL Novalike variables

- Variable stars which are insufficiently studied objects resembling novae by the characteristics of their light changes or by spectral features. This type includes, in addition to variables showing novalike outbursts, objects with no burst ever observed; the spectra of novalike variables resemble those of old novae, and small light changes resemble those typical for old novae at minimum light. However, quite often a detailed investigation makes it possible to reclassify some representatives of this highly inhomogeneous group of objects to other types. GCVS

The novalike group of variable stars is classified as insufficiently studied stars. These stars include stars with no observed bursts. They are included in this group because the spectra resemble old novae at minimum light. Quite often a detailed investigation makes it possible to reclassify some representatives of this highly inhomogeneous group into some other type of variable star.

We do not know exactly how novae look for the long interval between outbursts. According to the hibernation hypothesis, accretion can be dramatically reduced and novae may then not have the appearance of a novalike star. If the accretion rate and the magnetic field strength of the white dwarf are low enough then quasi-periodic disk instabilities can occur and the object will be classified as a dwarf nova. If the white dwarf is massive enough, greater than 0.6 solar mass, nova explosions can occur, and the object is classified as a nova if such an event has occurred in the last few decades and was properly recorded. In all other cases,

Observation

Mixed stars ✓v^ no amplitude no period <®> Visual, CCD/PEP

that is when signatures of accretion on the white dwarf via a disk or an accretion column are present in the spectrum and the object cannot be clearly classified as N or DN, it is classified as NL.

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