The FAST: Locally rare, brief events have an outsized impact on the Universe.
The heavy elements needed for life are synthesized in and dispersed by supernovae and neutron star mergers. Similarly, a single stellar superflare can evaporate an ocean or catalyze prebiotic pathways. The STAR-X wide field UV/X-ray design and fast and flexible operations captures these events.
The FURIOUS: Black holes grow extremely rapidly at early times in the Universe and are critical to galaxy evolution.
STAR-X will uniquely probe the physics of rapid accretion that allowed massive black holes to grow so quickly in the early Universe. STAR-X will catch transient, extreme black hole feeding events, such as TDEs, where entire stars are disrupted.
The FORMING: Distant galaxy clusters provide maximal leverage in evolutionary studies of structure formation and chemical enrichment.
STAR-X will conduct deep surveys and discover the elusive diffuse emission from the largest bound objects in the Universe (clusters of galaxies), shortly after their birth. STAR-X's combination of excellent imaging and low particle background (due to orbit choice) makes this possible in a way that no other mission can.
The STAR-X science goals and objectives also address key Decadal priorities:
STAR-X fills the gap in X-ray and UV time domain coverage in the late 2020s, providing simultaneous X-ray and UV observations that complement optical, infrared, and gravitational wave facilities.