19P/Borrelly

Comet Borrelly /bɒˈrɛli/ or Borrelly's Comet (official designation: 19P/Borrelly) is a comet with a period of 6.85 years that was visited by the spacecraft Deep Space 1 in 2001. The comet last came to perihelion (closest approach to the Sun) on February 1, 2022^[1][8] and will next come to perihelion on December 11, 2028.^[2]

19P/Borrelly closest Earth approach on 2028-Dec-05

Date & time of closest approach	Earth distance (AU)	Sun distance (AU)	Velocity wrt Earth (km/s)	Velocity wrt Sun (km/s)	Uncertainty region (3-sigma)	Reference
2028-Dec-05 19:12 ± 6 min	0.413 AU (61.8 million km; 38.4 million mi; 161 LD)	1.31 AU (196 million km; 122 million mi; 510 LD)	17.3	33.3	± 41 thousand km	Horizons

19P/Borrelly

Discovery
Discovered by	Alphonse Borrelly
Discovery date	December 28, 1904
Designations
Alternative names	1905 II; 1911 VIII; 1918 IV; 1925 VIII; 1932 IV; 1953 IV; 1960 V; 1967 VIII; 1974 VII; 1981 IV; 1987 XXXIII; 1994 XXX
Orbital characteristics
Epoch 2022-08-09 (JD 2459800.5)
Aphelion	5.90 AU[1]
Perihelion	1.306 AU[1]
Semi-major axis	3.61 AU
Eccentricity	0.6377
Orbital period (sidereal)	6.85 yr
Inclination	29.30°
Time of perihelion	2028-Dec-11[2] February 1, 2022 (last)[1]
Earth MOID	0.36 AU (54 million km)
Physical characteristics
Dimensions	8×4×4 km[3]
Mean radius	2.4 km[4]
Mass	2×1013 kg[5]
Mean density	0.3 g/cm3[6]
Albedo	0.03[7]

Perihelion distance at recent epochs[1]
Epoch	Perihelion (AU)
2028	1.310[2]
2022	1.306
2015	1.349
2008	1.355

Deep Space 1 returned images of the comet's nucleus from 3400 kilometers away. At 45 meters per pixel, it was the highest resolution view ever seen of a comet up until that time.^[9]

Discovery

The comet was discovered by Alphonse Borrelly during a routine search for comets at Marseille, France on December 28, 1904.

Exploration

Deep Space 1 flyby

Animation of Deep Space 1's trajectory from 24 October 1998 to 31 December 2003
   Deep Space 1 ·   9969 Braille ·   Earth ·   19P/Borrelly

On September 21, 2001 the spacecraft Deep Space 1, which was launched to test new equipment in space, performed a flyby of Borrelly. It was steered toward the comet during the extended mission of the craft, and presented an unexpected bonus for the mission scientists. Despite the failure of a system that helped determine its orientation, Deep Space 1 managed to send back to Earth what were, at the time, the best images and other science data from a comet.

The orbits of three periodic comets, 1P/Halley, 19P/Borrelly and 153P/Ikeya-Zhang, set against the orbits of the outer planets.