210P/Christensen

210P/Christensen
Comet 210P/Christensen imaged from an 8-in reflector on 1 December 2025
Discovery
Discovered byEric J. Christensen
Discovery siteCatalina Sky Survey
Discovery date26 May 2003
Designations
P/2003 K2, P/2008 X4
Christensen 1
Orbital characteristics
Epoch21 November 2025 (JD 2461000.5)
Observation arc22.99 years
Number of
observations		1,329
Aphelion5.797 AU
Perihelion0.524 AU
Semi-major axis3.161 AU
Eccentricity0.83408
Orbital period5.619 years
Inclination10.287°
93.797°
Argument of
periapsis		345.95°
Mean anomaly359.69°
Last perihelion22 November 2025
Next perihelion6 July 2031
TJupiter2.492
Earth MOID0.170 AU
Jupiter MOID0.019 AU
Physical characteristics
Dimensions0.87 km (0.54 mi)
Comet total
magnitude (M1)		14.9

210P/Christensen is a Jupiter-family comet with an orbital period of 5.7 years. It was discovered by Eric J. Christensen on 26 May 2003 in images taken by the Catalina Sky Survey and recovered in images obtained by STEREO, the first time a single-apparition comet was recovered by a spacecraft.

Observational history

Recovery image of the comet by STEREO on 13 December 2008
210P/Christensen on 30 December 2025 13:45 UT at magnitude 13.8 with a Unistellar smart telescope

Eric J. Christensen discovered the comet on 26 May 2003 in images taken with the 0.7-m Schmidt telescope of the Catalina Sky Survey. The comet had an estimated magnitude of 14.6 and a coma with an estimated diameter between 10 and 35 arcseconds and a faint tail. Further observations revealed the comet had a short orbital period.

In mid December 2008, Australian comet-hunter Alan Watson spotted in the STEREO/SECCHI Heliospheric Imager ("HI") HI-1B data a cometary object. Veteran German comet hunter Rainer Kracht recorded a few positions of the comet in the data and produced a set of very approximate orbital elements for it. Maik Meyer noticed the similarity of these orbital elements to those of P/2003 K2 and the link was confirmed by Brian G. Marsden. This was the first recovery of a single-apparition comet by a spacecraft. The comet was observed from the ground on 14 December 2008, located low and in bright twilight, and on 31 December 2008 it had an estimated magnitude of 10.5.

During the 2025 apparition, the comet passed 0.43 AU (64 million km; 40 million mi) from Earth on 8 November 2025 but was only 20 degrees from the Sun. It came to perihelion on 22 November 2025. It was visible in SWAN in November 2025 around magnitude 11. On 26 November it was visible low in the morning twilight, with a faint tail about a quarter of a degree long and an estimated magnitude of 9.5.

The comet has been locked in a 2:1 orbital resonance with Jupiter for the last 10,000 years and could be of asteroidal origin. Its nucleus is estimated to be about 1.74 km (1.08 mi) in diameter. It makes close approaches to Venus and on 17 September 1929 passed 0.032 AU (4.8 million km; 3.0 million mi) from Venus.

Notes

  1. ↑ Observation arc from the Minor Planet Center database covering dates from 26 May 2003 until 22 May 2026.

References

  1. 1 2 3 E. J. Christensen; R. Elliot; P. R. Holvorcem (27 May 2003). D. W. Green (ed.). "Comet C/2003 K2". IAU Circular. 8136 (1). Bibcode:2003IAUC.8136....1C.
  2. ↑ "Periodic Comet Names and Designations". Planetary Data System: Small Body Node. NASA. Retrieved 22 September 2026.
  3. 1 2 3 "210P/Christensen – JPL Small-Body Database Lookup". ssd.jpl.nasa.gov. Jet Propulsion Laboratory. Retrieved 20 July 2023.
  4. ↑ "210P/Christensen Orbit". Minor Planet Center. Retrieved 20 October 2025.
  5. ↑ "Horizons Batch for 210P/Christensen on 2031-Jul-06" (Perihelion occurs when rdot flips from negative to positive). JPL Horizons. Retrieved 14 December 2025. (Soln.date: 2025-Dec-03)
  6. 1 2 3 J. A. Fernández; A. Sosa (2015). "Jupiter family comets in near-Earth orbits: Are some of them interlopers from the asteroid belt?". Planetary & Space Science. 118: 14–24. Bibcode:2015P&SS..118...14F. doi:10.1016/j.pss.2015.07.010.
  7. 1 2 3 4 A. Patel (17 December 2008). "SECCHI Makes a Fantastic Recovery!". stereo.gsfc.nasa.gov. NASA / GSFC. Retrieved 12 December 2023.
  8. ↑ D. W. Green (7 June 2003). "Comet P/2003 K2 (Christensen)". IAU Circular. 8145 (2). Bibcode:2003IAUC.8145....2G.
  9. ↑ K. Battams; A. Watson; R. Kracht; M. Meyer; B. G. Marsden (December 2008). D. W. Green (ed.). "Comet P/2008 X4 = P/2003 K2 (Christensen)". IAU Circular. 9005 (1). Bibcode:2008IAUC.9005....1B.
  10. ↑ K. Kadota; B. G. Marsden (January 2009). D. W. Green (ed.). "Comet P/2008 X4 (Christensen)". IAU Circular. 9008 (2). Bibcode:2009IAUC.9008....2K.
  11. ↑ "Earth approach on 2025-Nov-08". JPL Horizons. Retrieved 14 December 2025.
  12. ↑ Olason, Mike (27 November 2025). "Bright Comet 210P/Christensen". Sky & Telescope. Retrieved 4 December 2025.