Overview
- A paper published November 9 reports that Chandra captured a powerful X-ray blast during an outburst and the data point to an unseen compact companion orbiting AT 2016blu every 113 days.
- Astronomers have tracked at least 27 bright optical eruptions from the luminous blue variable in NGC 4559 since 2012 that recur roughly every 113 days without destroying the star.
- The team’s model says the compact object pulls stellar gas at closest approach, forms a hot accretion disk that emits X-rays, and those X-rays heat pre-existing ejected gas so it glows in visible light.
- Estimated mass transfer is far above classical limits for a neutron star, raising questions about how the system sustains apparently super‑Eddington accretion and whether the accretor is a black hole or neutron star.
- The system is bright enough in X-rays to be a candidate ultra‑luminous X‑ray source, observers plan follow-up multiwavelength monitoring, and amateur contributions to the long optical record were crucial to timing the Chandra observation.