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.
In fact, supernovae come in different flavours, starting from different kinds of stars, ending up with different kinds of explosions, and producing different kinds of remnants. There are two main types of supernovae, the Type I and the Type II. I know this sounds a little counter intuitive, but let's start with the Type II first. These are the supernovae produced when massive stars die. We've done a whole show about that process, so if you want to watch it now, you can click here.