Komentarz do Diwrej ha-jamim I 2:26

Now Jerahmeel had another wife whose name was Atarah According to the simple meaning of the verse, she was an Israelitess, but in Yebamoth of the Palestinian Talmud (this is not found in our editions of Yebamoth, but in Yer. Sanh. 2:3) it is written that he took a gentile woman with whom to crown himself (עֲטָרָה). She was a beautiful princess.

she was the mother of Onam (I heard) that “mother” is like (Judg. 5:7): “I arose as a mother in Israel.” And she was the mother of Onam, and Onam is an expression meaning that he was humble and weak, an expression of mourning (אוֹנֵן), and like (Deut. 26:14): “I have not eaten of it in my mourning (בְאֹנִי),” and like (Num. 11:1): “... were as if in mourning over themselves (כְּמִתְאוֹנְנִים)” Sheshan, who gave his daughter to his Egyptian slave, Jarha, was descended from him, and [the Chronicler] tells of their disgrace; that is to say, they were not deserving of the kingship, and Ishmael the son of Nethaniah, the son of Elishama, who assassinated Gedaliah the son of Ahikam, was descended from him (Jer. 41:1).