Particle.news
Download on the App Store

Early Images of 2021 Novae Reveal Colliding Outflows and Delayed Ejections

An arXiv preprint links ejecta geometry to shock-driven gamma rays from nearby stellar eruptions.

Overview

  • Using the CHARA Array, astronomers imaged nova V1674 Herculis just 2–3 days after discovery and found two perpendicular outflows whose interaction likely produced the observed gamma rays.
  • Observations of the very slow nova V1405 Cassiopeiae indicate the bulk envelope was not expelled for more than 50 days, consistent with a temporary common-envelope phase before ejection.
  • Gemini spectra tracked evolving gas signatures that matched the imaged structures, reinforcing a picture of colliding flows that generate shocks and high-energy emission.
  • The results challenge the long-held view of novae as single, impulsive blasts by revealing multiple, interacting outflows and postponed mass loss.
  • The findings appear in a Dec. 8 arXiv preprint led by Elias Aydi and remain pending peer review, with further early imaging needed to assess how common these behaviors are.