19P/Borrelly

Comet· orbits the Sun

19P/Borrelly is a Jupiter-family comet that comes back to the inner Solar System about every 6.9 years. NASA's Deep Space 1 flew 2,171 km from its nucleus on 22 September 2001, and its pictures were the first high-resolution images of the nucleus of a Jupiter-family comet.

Open in 3D viewSee 19P/Borrelly in the live, interactive 3D map

Key facts

Perihelion

1.31 AU

Aphelion

5.91 AU

Orbital period

6.86 years

Eccentricity

0.6374

Science

Physical

Nucleus: ≈ 8.0 × 3.15 km (Deep Space 1)
Composition: A dark nucleus of ice and dust, shaped like a bowling pin, with jets of dust streaming from its sunlit side. Deep Space 1's infrared spectrometer found the surface hot and dry — about 300 to 345 K, with no water ice detected on it (Soderblom et al. 2002). Its mass has not been measured, so no density or gravity is shown.

Orbital

Semi-major axis: 3.61 AU; From catalogued orbital elements (MPC)
Eccentricity: 0.6374; From catalogued orbital elements (MPC)
Inclination: 29.30 °; From catalogued orbital elements (MPC)
Orbital period: 6.86 years; From catalogued orbital elements (MPC)
Perihelion: 1.31 AU; Computed from the orbital elements
Aphelion: 5.91 AU; Computed from the orbital elements
Mean orbital velocity: 15.7 km/s; Computed from the orbital elements

Activity

Perihelion distance: 1.31 AU
Becomes active within: 5 AU of the Sun

Radiation & temperature

Insolation: 0.0768 S⊕ · 8% of the sunlight Earth receives; Computed from the distance to the Sun (inverse-square; Earth's sunlight = 1), before any atmosphere.
Geometric albedo: 0.03; Geometric albedo 0.029 ± 0.006 (Buratti et al. 2004) — its Bond albedo, 0.009 ± 0.002, is among the lowest measured in the Solar System.
Equilibrium temperature: 145 K (-128 °C); Computed from albedo + distance from the Sun (airless black body); uses the geometric albedo as an estimate

Discovery & history

Discovered: December 28, 1904
By: Alphonse Borrelly (Marseille Observatory)
Name: Named after its discoverer, the French astronomer Alphonse Borrelly.

Alphonse Borrelly found it at Marseille Observatory on 28 December 1904. On 22 September 2001 NASA's Deep Space 1 flew past it, 2,171 km from the nucleus, on an extended mission after its star tracker had failed; its pictures were the first high-resolution images of the nucleus of a Jupiter-family comet.

2001Deep Space 1Flyby
Photographed the nucleus from 2,171 km, driven there by its ion engine.

Images

The nucleus of comet Borrelly from about 3,417 km, 160 seconds before Deep Space 1's closest approach — about 45 m per pixel — NASA / JPL (public domain) · NASA Photojournal

Borrelly's 8 km nucleus, lit from below, with a jagged line between day and night — NASA / JPL (public domain) · NASA Photojournal

Borrelly's nucleus, its dust jets and its coma from about 4,800 km — a composite in false colour — NASA / JPL (public domain) · NASA Photojournal

Images from open archives · credit shown per image