Daniel Rose
Abstract Circumstellar disk dissipation timescales constrain the window available for planet formation. At ∼9 Myr, IC 2395 lies at a critical epoch in primordial disk evolution, yet no kinematically selected disk census exists beyond the inner cluster core. A wide-field survey of IC 2395, extending to a 2° radius, establishes a kinematically selected disk census and evaluates the frequency of planet-forming environments in the outer cluster field. Using a high-purity catalogue of 173 members identified via Gaia DR3 kinematics, mid-infrared excesses are identified using AllWISE photometry. Candidates are classified into two tiers: cross-validated (corroborated by Gaia variability) and single-band detections. 21 disk candidates are identified, 90% of which lie beyond the footprint of prior Spitzer surveys. The candidates are concentrated among low-mass members (0.31–0.68 M ⊙ ), with no significant correlation between mass and excess (Spearman ρ = +0.07, p = 0.84). A secure disk fraction of 4.0% ± 1.5% is established by the cross-validated subsample, independently confirmed by Gaia DR3 young stellar object variability classification; a photometric 3 σ significance cut yields a consistent estimate of 2.9% ± 1.3%. An upper bound of 12.1% ± 2.5% is derived from all 21 W1 − W2 excess candidates, with a background-subtracted value of ∼10.1%. Gaia DR3 epoch photometry reveals diverse variability morphologies, including a dramatic dipper and multiple bursters, confirming ongoing magnetospheric accretion. By extending the survey radius, this work demonstrates that infrared excess sources indicative of inner-disk emission in IC 2395 are more abundant and widely distributed than previously recognized. The survival of these disks in the lower-density outer field provides a well-characterised sample for studying the final stages of disk evolution and planet formation.