The cat is defined as being in estrus, in heat or in season (i.e. likely to become pregnant if mated) if it shows behavioral characteristics that are typical of a female cat in heat and if it stands for the male cat and allows mating to occur (i.e. is receptive to mating).he feline estrus cycle, otherwise known as the female reproductive cycle or heat cycle of the female cat, is a repetitive cycle of seasonally and hormonally driven fluctuations in a female cat's fertility and sexual receptivity.
Type Ib/c and II-L, and possibly most Type IIn, supernovae are only thought to be produced from stars having near-solar metallicity levels that result in high mass loss from massive stars, hence they are less common in older, more-distant galaxies.
That is why they are closer towards the red side of the spectrum. Eventually the fusion of heavier elements will cause the formation of iron in most stars and the fusion process can't continue. Gravity then takes over and causes the star to collapse inward causing the material to rebound into what is a type 2 supernova. The only difference really is that with smaller stars like the sun the fusion won't continue until there is iron, but rather the star will blow off outer layers since the star is not big enough and will leave behind a white dwarf.