2I/Borisov
The second confirmed interstellar object and the first that was unmistakably a comet, discovered in August 2019 by amateur astronomer Gennadiy Borisov. Its eccentricity of about 3.4 made its interstellar origin certain. Unlike 1I/ʻOumuamua it showed an active dust coma and tail, letting astronomers study the chemistry of a comet formed around another star; it proved unusually rich in carbon monoxide.
Note
The first interstellar object with clear cometary activity, allowing spectroscopy of material from another planetary system.
Physical & orbital character
How it was identified
Knowledge connections
- Trajectory classInterstellar Hyperbolic Trajectory
- Associated withExcess Hyperbolic Velocity
- Associated withSpectroscopic Composition Analysis
- Catalogued inMinor Planet Center
- Catalogued inNASA Jet Propulsion Laboratory
Sources
The primary and reference sources this topic draws on.
- Minor Planet CenterIAU Minor Planet Center
Designations and orbits of asteroids, comets, and minor bodies.
- NASA JPLJet Propulsion Laboratory / Solar System Dynamics
Orbital data, ephemerides, and small-body parameters for planets, asteroids, and comets.
- NASANational Aeronautics and Space Administration
Mission data, planetary science, space telescopes, and public-domain imagery.
Most NASA-produced imagery is in the public domain; individual items are checked for usage terms before publication.
- ESAEuropean Space Agency
European missions, observatories, and space science imagery.
- ESOEuropean Southern Observatory
Southern-hemisphere observatory data and imagery (VLT, ALMA partner).