135-Myr Aligned Orbit Reveals How Migration Locks in Before Disks Dissipate

The SOYSAUCE II preprint (arXiv:2606.09973, v1, 8 Jun 2026) validates TIC 150070085 b, a 3.6 R_E planet on a 10.47-day orbit around a 135±10 Myr member of Alessi 84, and flags a candidate 3.0 R_E companion near 3:2 resonance. Using MAROON-X Rossiter-McLaughlin observations, the team measures a sky-projected obliquity |λ| = 18±12°, consistent with alignment. Methodology relies on TESS photometry for transit timing variations, ground-based follow-up for validation, and color-magnitude plus rotation data to refine cluster age; sample size is a single system. As a preprint the result awaits peer review and carries the usual limitations of young-star activity jitter and the inability to constrain true 3D obliquity. This measurement bridges the gap between <50 Myr systems still embedded in gas disks and Gyr-old mature populations where alignment is the norm. It supports disk-driven migration models in which eccentricity damping and inclination damping occur before the disk dissipates, rather than later high-eccentricity migration. Complementary evidence appears in the aligned orbit of the ~120 Myr planet DS Tuc Ab (Zhou et al. 2020, AJ) and the statistical preference for low obliquity among planets younger than 300 Myr compiled by Albrecht et al. (2022, ApJ). The near-resonant candidate further implies that convergent migration can trap pairs before atmospheric escape strips envelopes, directly linking formation pathways to future habitability assessments once JWST transmission spectra become feasible.