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 Deep Space 1 spacecraft in 2001. The comet last came to perihelion (closest approach to the Sun) on 1 February 2022^[2][7] and will next come to perihelion on 11 December 2028.^[3]

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	± 35 thousand km	Horizons

19P/Borrelly

The nucleus of Comet Borrelly as seen by NASA's Deep Space 1 mission in 22 September 2001.
Discovery
Discovered by	Alphonse Borrelly
Discovery site	Marseille, France
Discovery date	28 December 1904
Designations
MPC designation	P/1904 Y2, P/1911 S1
Alternative designations	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[1][2]
Epoch	9 August 2022 (JD 2459800.5)
Aphelion	5.90 AU
Perihelion	1.306 AU
Semi-major axis	3.61 AU
Eccentricity	0.6377
Orbital period	6.85 years
Inclination	29.30°
Last perihelion	1 February 2022
Next perihelion	11 December 2028[3]
Earth MOID	0.36 AU
Physical characteristics[1]
Dimensions	8.0 × 4.0 × 4.0 km (5.0 × 2.5 × 2.5 mi)[4]
Mass	2×1013 kg[a]
Mean density	0.3 g/cm3[5]
Geometric albedo	0.022[6]
Comet total magnitude (M1)	9.8
Comet nuclear magnitude (M2)	13.2

Perihelion distance at recent epochs[2]
Epoch	Perihelion (AU)
2028	1.310[3]
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.^[8]

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.

Notes

1. Using the volume of an ellipsoid of 8x4x4 km * a rubble pile density of 0.3 g/cm³ yields a mass (m=d*v) of 2.0×10¹³ kg