When the helium core ignites in an IMS , it may execute a blue loop .
When the helium core ignites in an IMS , it crosses the instability strip again , once while evolving to high temperatures and again evolving back towards the asymptotic giant branch .
When the helium core ignites in an IMS , it may execute a blue loop and crosses the instability strip again , once while evolving to high temperatures and again evolving back towards the asymptotic giant branch .