This week’s character is 星 (sing1) which means “star” but is also used to refer to the days of the week. For example, Monday is 星期一 (sing1 kei4 yat1).
It’s made of up two characters that we learned earlier! The top part is the character 日 (jat6) and the bottom part is 生 (saang1/sang1).
It used to be written with THREE 日 (jat6) characters (晶 zing1 for sparkling) but was later simplified to just the one 日 (jat6) character.
I like to think that we use 星 (sing1) to refer to the days of the week because the character symbolizes the birth of a new day.