19P/Borrelly

19P/Borrelly

Discovery
Discovered by	Alphonse Borrelly
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 September 8, 2001 (JD 2452160.5)
Aphelion	5.83 AU
Perihelion	1.35 AU (May 28, 2015)[1]
Semi-major axis	3.59 AU
Eccentricity	0.624
Orbital period	6.8 a
Inclination	30.3°
Physical characteristics
Dimensions	8×4×4 km[2]
Mean radius	2.4 km[3]
Mass	2×10^13 kg[4]
Mean density	0.3 g/cm³[5]
Albedo	Albedo: 0.03[6]

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

Comet Borrelly or Borrelly's Comet (official designation: 19P/Borrelly) is a periodic comet, which was visited by the spacecraft Deep Space 1 in 2001. The comet last came to perihelion (closest approach to the Sun) on May 28, 2015.^[1] The comet's nucleus, seen in the image on the right, is particularly notable for being shaped like a bowling pin.

Discovery

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

Deep Space 1 flyby

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.

References

1. Seiichi Yoshida (2014-08-10). "19P/Borrelly". Seiichi Yoshida's Comet Catalog. Retrieved 2014-10-29.
2. Weaver, H. A.; Stern, S.A.; Parker, J. Wm. (2003). "Hubble Space Telescope STIS Observations of Comet 19P/BORRELLY during the Deep Space 1 Encounter". The American Astronomical Society. 126 (1): 444–451. Bibcode:2003AJ....126..444W. doi:10.1086/375752. Retrieved 2008-12-16.
3. http://solarsystem.nasa.gov/planets/profile.cfm?Object=Com_19PBorrelly&Display=Facts&System=Metric
4. Using the volume of an ellipsoid of 8x4x4km * a rubble pile density of 0.3 g/cm³ yields a mass (m=d*v) of 2.0E+13 kg.
5. D. T. Britt; G. J. Consol-magno SJ; W. J. Merline (2006). "Small Body Density and Porosity: New Data, New Insights" (PDF). Lunar and Planetary Science XXXVII. Archived (PDF) from the original on 17 December 2008. Retrieved 2008-12-16.
6. Robert Roy Britt (2001-11-29). "Comet Borrelly Puzzle: Darkest Object in the Solar System". Space.com. Archived from the original on 22 January 2009. Retrieved 2008-12-16.

External links

• http://jcometobs.web.fc2.com/pcmtn/0019p.htm
• 19P – Gary W. Kronk's Cometography
• Elements and Ephemeris for 19P/Borrelly – Minor Planet Center