Arundhati was another name for sanctity and there is an interesting story in the puranas which narrates her marriage to Sage Vasishta. So high was her purity that Arundhati turned sand to rice.
Once, Sage Vasistha was going around in search of a person who would cook the sand in his hand and turn it into rice and feed him with that.
Sage Vasistha travelled around the world looking for a person who could perform this unheard deed.
Finally he met Arundhati in a village. She promised him that he could convert the sand in his hands to rice and feed him.
She put the sand in a pot and then meditated on the Supreme Deity.
Her devotion and single-pointed attention converted the sand into rice. She cooked it and fed Vasishta.
Impressed by this, Sage Vasishta married Arundhati.
Arundhati shines as a as star in the sky. It is a tradition to look at the star on Holy occasions.