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Hale-Bopp

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Credit: E. Kolmhofer, H. Raab (Johannes-Kepler-Observatory, CC BY-SA 3.0) CC BY-SA 3.0 — attribution required
COMET

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).

Physical Properties

30 km

Orbit

Sun
186 AU
0.995086
89.43°
0.914 AU
370.8 AU
2533 yr

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: 2026-04-18 18:19:27.

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.