**IAU Circular**
**Definition**
The IAU Circular is a formal publication issued by the International Astronomical Union (IAU) that announces new astronomical discoveries, such as novae, supernovae, comets, and other transient celestial events. It serves as an official rapid communication tool for the global astronomical community.
—
## Overview
The IAU Circulars have been published since 1922 and are distributed to professional astronomers and observatories worldwide. They provide timely and concise information about newly observed phenomena, including coordinates, brightness, and other relevant observational data. The circulars play a crucial role in coordinating follow-up observations and confirming discoveries.
## Purpose and Content
The primary purpose of the IAU Circular is to disseminate verified information about transient astronomical events quickly. Typical content includes announcements of new comets, novae, supernovae, variable stars, and other noteworthy celestial occurrences. Each circular is numbered sequentially and contains brief reports submitted by astronomers, often accompanied by observational details and references.
## Distribution and Access
Historically distributed in printed form, the IAU Circulars are now primarily available electronically to subscribers, including research institutions and observatories. This rapid distribution system ensures that astronomers worldwide can respond promptly to new discoveries, facilitating collaborative research and observation.
—
**Meta Description:**
The IAU Circular is an official publication by the International Astronomical Union that announces new astronomical discoveries and transient events. It provides rapid communication to the global astronomical community.