Later spectroscopic analysis suggested that the star was not a nova, but had instead undergone a very late thermal pulse similar to that of V605 Aquilae, causing it to vastly expand.

V605 Aquilae, which was discovered in 1919, is the only other star known to have been observed during the high luminosity phase of a very late thermal pulse, and models predict that Sakurai's Object, over the next few decades, will follow a similar life cycle.

Nakano wrote that "While the outburst [suggests] a slow or symbiotic nova, the lack of obvious emission lines one year after brightening is very unusual.

[16][17] Observations from the United Kingdom Infrared Telescope (UKIRT) in 1999 revealed that the star is in a RCB-like phase with the release of dust and huge loss of mass.

[5] Sakurai's Object is a highly evolved post-asymptotic giant branch star which has, following a brief period on the white dwarf cooling track, undergone a helium shell flash (also known as a very late thermal pulse).

[6] Observations of Sakurai's Object show increasing reddening and pulsing activity, suggesting that the star is exhibiting thermal instability during its final helium-shell flash.

[5] V605, discovered in 1919, is the only other known star observed during the high luminosity phase of a very late thermal pulse, and Sakurai's Object is modeled to increase in temperature in the next few decades to match the current state of V605.

[10] For example, Sakurai's Object is a prime target to study the recombination that occurs after planetary nebulae are ionized, because the conditions would be very difficult to replicate in a laboratory.