Answer

Vasupujya Bhagwan ka Chyavan Kalyanak Jeth Sud 9 (Shukla Navami) ko manaaya jata hai. Kuch Jain sources mein iske saath Prānat Shatabhishā nakshatra bhi diya gaya hai. ( jainqq.org)

Explanation

Chyavan Kalyanak woh pavitra kshan hota hai jab Tirthankar ka jiva maa ke garbh mein aata hai. Vasupujya Bhagwan ke liye yeh tithi Jyeshtha Shukla Navami batayi gayi hai. ( jainqq.org)

Takeaway

Yeh Panch Kalyanakon mein ek bahut mangal aur gauravshali avsar hai. ( jainfoundation.in)