88P/Howell

88P/Howell
88P/Howell on 14 June 2026 at 11:01 UT imaged with a Unistellar 114mm smart telescope.
Discovery
Discovered byEllen S. Howell
Discovery sitePalomar Observatory
Discovery date29 August 1981
Designations
P/1981 Q1, P/1987 E1
  • 1981 X, 1987 VI, 1993 II
  • 1981k, 1987h, 1992c
Orbital characteristics
Epoch9 June 2026 (JD 2461200.5)
Observation arc71.26 years
Earliest precovery date22 May 1955
Number of
observations		5,478
Aphelion4.860 AU
Perihelion1.358 AU
Semi-major axis3.109 AU
Eccentricity0.56327
Orbital period5.482 years
Inclination4.3819°
56.667°
Argument of
periapsis		235.86°
Mean anomaly14.788°
Last perihelion18 March 2026
Next perihelion8 September 2031
TJupiter2.947
Earth MOID0.344 AU
Jupiter MOID0.475 AU
Physical characteristics
Mean radius
0.96 km (0.60 mi)
Comet total
magnitude (M1)		11.4
Comet nuclear
magnitude (M2)		13.9

88P/Howell is a Jupiter-family comet with a 5.5 year orbital period around the Sun. It is the only comet independently discovered by American astronomer, Ellen Howell.

Observational history

Infrared image of 88P/Howell taken by NEOWISE on 9 June 2020

It was discovered on 29 August 1981 by Ellen Howell. Alan C. Gilmore and Pamela M. Kilmartin recovered the comet ahead of its next apparition on 6 March 1987 as a diffuse 18th-magnitude object in the night sky. During the 2009 apparition the comet became as bright as apparent magnitude 8.

The comet most recently came to perihelion on 18 March 2026. It will next come to perihelion on 8 September 2031 and on 14 September 2031 it will pass 0.074 AU (11.1 million km; 6.9 million mi) from Mars. Between 2000–2050 the closest the comet will come to Earth is 0.76 AU (114 million km; 71 million mi) in June 2042.

During the 2020 apparition the comet reached about magnitude 9.

During the 2026 apparition 88P/Howell reached about magnitude 10. It crossed the Celestial equator on 19 May 2026 becoming more visible from the Northern hemisphere at magnitude 11.

Orbit

As of 2026, 88P/Howell currently has an orbit that takes it between 1.36–4.86 AU (203–727 million km) from the Sun. Brian G. Marsden was the first to compute two orbital solutions for the comet in 8 September 1981, where he determined that the comet follows a periodic orbit around the Sun once every 5.94 years. Prior to discovery, 88P/Howell had a larger orbit until a close encounter with Jupiter reduced it after passing at a distance of 0.58 AU (87 million km) from the giant planet.

On 14 September 2031, it will pass 0.073 AU (10.9 million km) from Mars.

Physical characteristics

Initial estimates of the size of its nucleus place it roughly about 4.4 km (2.7 mi) in diameter. However, infrared observations from the Spitzer Space Telescope in 2006 reveal a smaller nucleus of only about 1.92 km (1.19 mi) in diameter.

Proposed exploration

In response to the New Frontiers program call for Mission 4, a team from Applied Physics Laboratory (APL) submitted a mission concept proposal called the Comet Rendezvous, Sample Acquisition, Investigation, and Return (CORSAIR) that would perform a sample return from comet 88P/Howell. The mission proposed using a harpoon-based sample acquisition system while the spacecraft itself hovers a few meters above the comet's surface. In 2019, CORSAIR was ultimately not selected in favor of the Dragonfly mission to Titan.

In 2026, 88P/Howell is selected as a backup target for another proposed NASA/JPL sample-return mission called Gelato, which could launch and rendezvous to the comet by 2030 and 2038 respectively in case its primary target, 67P/Churyumov–Gerasimenko, is unreachable.

Notes

  1. ↑ Observation arc from the Minor Planet Center database covering dates from 22 May 1955 until 25 August 2026.
  2. ↑ For comparison, 3I/ATLAS passed about 0.194 AU (29.0 million km) from Mars on 3 October 2025, while C/2013 A1 (Siding Spring) flew by the Red Planet at a distance of 138,700 km (0.000927 AU) on 19 October 2014.

References

  1. 1 2 E. S. Howell; C. Kowal (1 September 1981). B. G. Marsden (ed.). "Comet Howell (1981k)". IAU Circular. 3631 (1). Bibcode:1981IAUC.3631....1H.
  2. ↑ "Comet Names and Designations". International Comet Quarterly. Retrieved 18 August 2026.
  3. 1 2 3 4 "88P/Howell – JPL Small-Body Database Lookup". ssd.jpl.nasa.gov. Jet Propulsion Laboratory. Retrieved 13 March 2026.
  4. 1 2 "88P/Howell Orbit". Minor Planet Center. Retrieved 1 November 2014.
  5. 1 2 "Horizons Batch for 88P/Howell on 2031-Sep-08" (Perihelion occurs when rdot flips from negative to positive). JPL Horizons. Retrieved 28 March 2026. (Soln.date: 2025-Dec-03)
  6. 1 2 G. Tancredi; J. A. Fernández; H. Rickman; J. Licandro (2006). "Nuclear magnitudes and the size distribution of Jupiter family comets". Icarus. 182 (2): 527–549. Bibcode:2006Icar..182..527T. doi:10.1016/j.icarus.2006.01.007.
  7. ↑ A. C. Gilmore; P. M. Kilmartin (9 March 1987). B. G. Marsden (ed.). "Periodic Comet Howell (1987h)". IAU Circular. 4335 (1). Bibcode:1987IAUC.4335....1.
  8. 1 2 3 4 Seiichi Yoshida. "88P/Howell". Seiichi Yoshida's Comet Catalog. Retrieved 1 March 2010.
  9. 1 2 "88P/Howell plot at Comet Observation database (COBS)". Retrieved 13 March 2026.
  10. ↑ A. C. Gilmore; P. M. Kilmartin (8 September 1981). B. G. Marsden (ed.). "Comet Howell (1981k)". IAU Circular. 3635 (1). Bibcode:1981IAUC.3635....1G.
  11. 1 2 E. S. Howell; C. Kowal; S. J. Bus; et al. (11 September 1981). B. G. Marsden (ed.). "Periodic Comet Howell (1981k)". IAU Circular. 3636 (1). Bibcode:1981IAUC.3636....1H.
  12. ↑ J. V. Scotti (1994). "Comet Nuclear Magnitudes". Bulletin of the American Astronomical Society. 26: 1375. Bibcode:1994AAS...185.4306S.
  13. ↑ S. A. Sandford; N. L. Chabot; N. Dello Russo; J. C. Leary; et al. (23–28 July 2017). CORSAIR (COmet Rendezvous, Sample Acquisition, Investigation, and Return): A New Frontiers Mission Concept to Collect Samples from a Comet and Return them to Earth for Study (PDF). 80th Annual Meeting of the Meteoritical Society. Santa Fe, New Mexico. Bibcode:2017LPICo1987.6125S.
  14. ↑ S. Völk; S. Ulamec; J. Biele; et al. (2018). "Development and testing of a pyro-driven launcher for harpoon-based comet sample acquisition". Acta Astronautica. 152: 218–228. Bibcode:2018AcAau.152..218V. doi:10.1016/j.actaastro.2018.07.045.
  15. ↑ M. Wall (28 June 2019). "NASA Is Sending a Life-Hunting Drone to Saturn's Huge Moon Titan". Space.com. Retrieved 18 August 2026.
  16. ↑ M. J. Kinkczyk; G. E. Buffo; L. M. Aaron-Hennig; et al. (2026). "Gelato: A Mission Concept for Comet Surface Sample Return". The Planetary Science Journal. 7 (7): 182. doi:10.3847/PSJ/ae771f. hdl:11311/1329074.