P/2007 R5

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**P/2007 R5 (SOHO)**
Discovery
Discovered by:	Terry Lovejoy, Kazimieras Cernis, Bo Zhou, and Sebastian Hönig
Discovery date:	September 4, 1999
Alternate designations:	P/1999 R1, P/2003 R5
Orbital characteristics ^A
Aphelion distance:	4.9903 AU
Perihelion distance:	0.0570 AU
Semi-major axis:	2.5237 AU
Eccentricity:	0.9774
Orbital period:	4.01 a
Inclination:	13.676°
Last perihelion:	September 11, 2007
Next perihelion:	September 7, 2011

Comet P/2007 R5 (SOHO), also designated P/1999 R1 and P/2003 R5, is the first periodic comet to be discovered using the automated telescopes of the SOHO (SOlar and Heliospheric Observatory) spacecraft.

The periodicity of P/2007 R5 was predicted by Sebastian F. Hönig, a German graduate student and prolific asteroid discoverer, in 2006 ^[1]. The announcement of the new periodic comet was made after the predicted return was confirmed by SOHO and observer B. Zhou on 10 September 2007 ^[2]. Out of approximately 1,350 SOHO-observed sungrazer comets, this is the first to be verified as a short-period comet; most sungrazers are long-period comets on near-parabolic orbits that do not repeat for thousands of years, if at all.

As it passed to within 7.9 million kilometres of the Sun, around 5% of the distance from the Earth to the Sun, it brighten by a factor of around a million. This is common behavior for a comet.^[3]

P/2007 R5 is probably an extinct comet. Extinct comets are those that have expelled most of their volatile ice and have little left to form a tail or coma. They are theorized to be common objects amongst the celestial bodies orbiting close to the Sun. P/2007 R5 (SOHO) is probably only 100-200 meters in diameter.^[3]

It is due to return in September 2011.^[3]

Discovery credit goes to Terry Lovejoy (Australia, 1999), Kazimieras Černis (Lithuania, 2003), and Bo Zhou (China, 2007).