Understanding the impact of magnetic fields and turbulence on the lifetime of the First core

Yuichi Sakamoto  (Kagoshima University)

In the early stages of the star formation process, theoretical predictions suggest the formation of a very short-lived object supported by pressure with a radius of approximately 1 AU, known as the First core. Although several candidate objects for the First core have been identified, none have been definitively discovered yet. The probability of discovery is proportional to the lifetime of the First core, making it crucial to determine this lifetime for future observations. Previous simulations have indicated that the lifetime of the First core is influenced by factors such as the rotation of the initial molecular cloud core and the strength of the magnetic field, with estimates ranging from a few hundred to a few thousand years. Some long-lived First cores, lasting over 10,000 years, have been reported, such as by Tomida et al. (2010). However, earlier studies often neglected magnetic fields and turbulence, and simplified radiative transfer. Therefore, this study conducts radiation non-ideal magnetohydrodynamic simulations to estimate the lifetime of the First core, considering both magnetic fields and turbulence.