19P/Borrelly
              < 19P 
 
            
          | Discovery | |
|---|---|
| Discovered by | Alphonse Borrelly | 
| Discovery date | December 28, 1904 | 
| 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 | |
| Epoch 2022-08-09 (JD 2459800.5) | |
| Aphelion | 5.90 AU | 
| Perihelion | 1.306 AU | 
| 3.61 AU | |
| Eccentricity | 0.6377 | 
| 6.85 yr | |
| Inclination | 29.30° | 
| 2028-Dec-11 February 1, 2022 (last) | |
| Earth MOID | 0.36 AU (54 million km) | 
| Physical characteristics | |
| Dimensions | 8×4×4 km | 
| 2.4 km | |
| Mass | 2×1013 kg | 
| Mean density | 0.3 g/cm3 | 
| Albedo | 0.03 | 
| Perihelion distance at recent epochs | |||||||
| Epoch | Perihelion (AU) | ||||||
|---|---|---|---|---|---|---|---|
| 2028 | 1.310 | ||||||
| 2022 | 1.306 | ||||||
| 2015 | 1.349 | ||||||
| 2008 | 1.355 | ||||||
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 and will next come to perihelion on December 11, 2028.
| 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 | 
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.