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.
A supernova (/ Ë s uË p Ér n oÊ v É / plural: supernovae / Ë s uË p Ér n oÊ v iË / or supernovas, abbreviations: SN and SNe) is a transient astronomical event that occurs during the last stellar evolutionary stages of a massive star's life, whose dramatic and catastrophic destruction is marked by one final titanic explosion.