Śrīmad-Bhāgavatam · Text 6.12.33
Who is speaking and story frame
वज्रस्तु तत्कन्धरमाशुवेग:
कृन्तन् समन्तात् परिवर्तमान: ।
न्यपातयत् तावदहर्गणेन
यो ज्योतिषामयने वार्त्रहत्ये ॥ ३३ ॥
vajras tu tat-kandharam āśu-vegaḥ
kṛntan samantāt parivartamānaḥ
nyapātayat tāvad ahar-gaṇena
yo jyotiṣām ayane vārtra-hatye
Although the thunderbolt revolved around Vṛtrāsura’s neck with great speed, separating his head from his body took one complete year — 360 days, the time in which the sun, moon and other luminaries complete a northern and southern journey. Then, at the suitable time for Vṛtrāsura to be killed, his head fell to the ground.
Read this verse on Vedabase.ioThis verse has no purport; its meaning is explained by the verses around it.