Hale-Bopp

The "Great Comet of 1997" — one of the brightest, longest-visible comets of modern times.

Orbits Sun

Naked-eye visible for a record 18 months (May 1996 – Dec 1997).
Brightest comet since 1811 at peak in April 1997.
Unusually large nucleus (~60 km).

About Hale-Bopp

C/1995 O1 (Hale-Bopp), discovered independently by Alan Hale and Thomas Bopp on 23 July 1995, became one of the most spectacular comets of the 20th century. It was visible to the naked eye for a record 18 months — from May 1996 to December 1997 — and outshone every star except Sirius in the spring of 1997. Its nucleus, estimated at 60 km across, is among the largest known.

Physical Properties

Mean radius30 km

Orbit

OrbitsSun

Semi-major axis186 AU

Eccentricity0.995086

Inclination89.43°

Perihelion0.914 AU

Aphelion370.8 AU

Orbital period2533 yr

Gallery

Hand-picked mission imagery of Hale-Bopp sourced from NASA and partner archives. Click any photo for full resolution and source attribution.

Comet Hale-Bopp's nucleus and dust jets, from the Hubble Space Telescope. NASA/JPL/STScI · Public Domain u2014 NASA Media Usage Guidelines

Hubble sees material ejected from the nucleus of comet Hale-Bopp. — Hubble sees material ejected from the nucleus of… NASA/JPL/STScI

Imagery on this page is provided by the original mission teams. Full attribution terms: Image Rights & Credits.

Sources & Further Reading

Numerical values (radius, mass, orbital elements, temperatures) are drawn from NASA NSSDC Planetary Fact Sheets, JPL Horizons, and the JPL Small-Body Database. Last refreshed: 2026-06-08 01:37:02.