Searching for the Onset of Magnetic Dynamos in the Earliest Protostars

X-rays from young, pre-main sequence (pre-MS) stars play an important role in the chemical evolution of circumstellar disks and the eventual formation of planets. Low‑mass (≲2 M⊙) pre-MS stars are prolific X‑ray sources because their rapid spin and vigorous magnetic dynamo heat their coronae to several million degrees Kelvin. Decades of observations with Chandra and XMM‑Newton have cata- logued thousands of such stars, confirming that hot coronae are a standard feature of pre‑MS evolution. Yet, the epoch at which coronal activity begins remains uncertain and has important implications towards accretion physics and early disk chemistry. The earliest protostellar stage of evolution, the so-called ’Class 0’ phase, represents the first∼100,000 years of a star’s life. Numerical simulations pre- dict that even during this phase dynamo‑driven magnetic fields can arise, but observational evidence of X‑ray emission from Class 0 objects is scarce. High‑sensitivity, high‑resolution surveys with ALMA and the VLA have uncovered several hundred nearby Class 0 protostars. Harnessing∼25 years of archival Chandra and XMM‑Newton data, we present a preliminary analysis of X‑ray counterparts among this Class 0 sample. The detection of X‑ray emission in these candidates likely represent the youngest cohort of X‑ray emitting protostars identified to date, offering important insight into the onset of coronal activity and its influence on the earliest stages of star and planet formation.