startrax — Jaxstro — Anna Rosen, Ph.D.

A differentiable map from (initial mass, age, metallicity) to full stellar state — winds, mass loss, lifetimes, remnants — with a differentiable binary-evolution layer in progress.

Readiness

In developmentIn active development

What's working

Three panels. Left: Hertzsprung-Russell tracks for 20 to 50 solar-mass stars, coloured by evolutionary phase from main sequence through Hertzsprung gap, core helium burning, early asymptotic giant branch and helium star. Centre: current stellar mass against age, showing tracks that coincide until winds switch on near 4 to 6 megayears and then drop by different amounts under weak, fiducial and strong wind controls, each ending in a marker for eventual neutron-star or black-hole formation. Right: a heat map of the change in remnant mass across initial mass and eruptive-wind control, negligible below 40 solar masses and strongly signed above it, with an inset showing pre-supernova mass falling linearly with the wind control and its exact adjoint derivative. — PreliminaryDifferentiable massive-star evolution connects uncertain winds to remnant outcomes. (a) Phase-colored H–R tracks and (b) mass-loss histories for $20$ – $50\,M_\odot$ stars under weak, fiducial, and strong wind controls (dotted, solid, and dashed). The tracks coincide before wind activation and diverge as mass loss reshapes their evolution; symbols indicate eventual neutron-star or black-hole formation. (c) Wind-induced changes in remnant mass across the $(M_{\rm ZAMS},W)$ response surface. The inset demonstrates an exact local adjoint sensitivity of pre-supernova mass—enabling gradient-based inference through stellar evolution rather than repeated parameter sweeps.

What's coming

In active development. The differentiable binary-evolution layer is the current front.