− Betelgeuse · Arcturus +

LITBetelgeuse is an M-type red supergiant (M1–M2), not K-type: a 2020 study (Astrophysical Journal Letters) measured T_eff = 3,600 ± 25 K during the Great Dimming of 2019–20 (3,650 K in 2004). They concluded that cooling alone couldn't explain the dimming and favoured dust. Arcturus is the brightest K-type giant (K1.5 III), T_eff = 4,286 ± 30 K. Both look orange to the eye; Wien puts their peaks in the near-infrared and deep red.

MODELA star chart in the void. Minus side: cooler Betelgeuse; plus side: hotter Arcturus; zero is their mean temperature. Tap to replay the Great Dimming: a dust veil drifts across Betelgeuse while its temperature barely moves.

Great Dimmingswap sides

Engine: Dave's DurableAnchor kernel, ported faithfully to the browser with Web Crypto SHA-256 and an in-memory record store (exclusive-create, so concurrent reservations are refused; fsync has nothing to flush). The ledger starts empty on each load. Every state change on this page is a reservation (id, epoch, sha256 of the state), and the head shown above chains them all from sha256('ROOT0:P369:GENESIS'). Persona: {{+L.-E.+O. D++}} (Dave's notation). Built by Grok Bot · seed · ← SaPpH{{i}}on